ENS LyonAmphithéâtre Mérieux

Friday Jan 8th, 2016

ABSTRACT BOOK

VerMidi XIX

AmphitéâtreCharles Mérieux

Mathieu Baritaud (INMG, Lyon)The anti-apoptotic CED-9/Bcl-2 protein protects against muscle degeneration in Caenorhabditis elegans models for muscular dystrophies

VERMIDI XIX PROGRAM9:30 - 10:00

10:00 - 10:45Welcome BreakfastKeynote Lecture: Mario De BonoInto the unknome: high throughput genetics and novel neural functions

10:45 - 12:00 Session 1

10:45 - 11:05 Marie Gendrel (Columbia University, New York)The GABAergic system: not a closed chapter.

11:05 - 11:25 Adeline Mergoud Dit Lamarche (INMG, Lyon)Identification of a transcription factor as determinant of muscle aging in C. elegans

11:25 - 11:45 Sonia El Mouridi (INMG, Lyon)A streamlined protocol to facilitate CRISPR/Cas9 genome engineering using a highly efficiency sgRNA and an easily selectable phenotype

11:45 - 12:00 A word from our sponsorsHybrigenics – GATC Biotech – Bioaxial

15:00 - 15:20 Flore Beurton (LBMC, Lyon)Characterization of the SET1/MLL complex in C. elegans

15:20 - 15:40 Le He (CIML, Marseille)Dissecting a worm killer

15:40 - 16:00 Clara Taffoni (CIML, Marseille)Host response to fungal infection and wounding in C. elegans epidermis

16:00 - 16:20 Thanh Vuong-Brender (UPMC, Paris)Composition, organization and mechanical contribution of C. elegans embryonic sheath to embryonic integrity and elongation

12:00 - 15:00 Lunch / Poster Session

15:00 - 16:20 Session 2

17:00 - 17:20

Jane Deuve (UPMC, Paris)Control of autophagy during worm development via an intronic region

17:20 - 17:40 Fabrice Besnard (IBENS, Paris)Mapping and identifying mutations causing rapid evolution in a cell fate using Mutation Accumulation lines in C. elegans and C. briggsae

17:40 - 18:00 Lisa Martino (IJM, Paris)Polo-like kinase is required for nuclear envelope breakdown in early C. elegans embryo

18:00 - 18:20

16:20 - 17:00 Coffee break

17:00 - 18:20 Session 3

18:30 Happy Hour

Amphithéâtre MérieuxPlace de l'École, 69007 Lyon, France

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SPONSORS

Table of contents

The GABAergic system: not a closed chapter., Marie Gendrel [et al.] . . . . . . . . . . . 5

Identification of a transcription factor as determinant of muscle aging in Caenorhabditiselegans, Adeline Mergoud Dit Lamarche [et al.] . . . . . . . . . . . . . . . . . . . . . . . 6

A streamlined protocol to facilitate CRISPR/Cas9 genome engineering using a highlye�ciency sgRNA and an easily selectable phenotype, Claire Lecroisey [et al.] . . . . . . 7

A word from our sponsors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Characterization of the SET1/MLL complex in C. elegans, Flore Beurton [et al.] . . . . 9

Dissecting a worm killer, Le He [et al.] . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Host response to fungal infection and wounding in C. elegans epidermis, Clara Ta↵oni [etal.] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Composition, organization and mechanical contribution of C. elegans embryonic sheathto embryonic integrity and elongation, Thanh Vuong-Brender [et al.] . . . . . . . . . . . 12

The anti-apoptotic CED-9/Bcl-2 protein protects against muscle degeneration in Caenorhab-ditis elegans models for muscular dystrophies, Mathieu Baritaud [et al.] . . . . . . . . . 13

Mapping and identifying mutations causing rapid evolution in a cell fate using MutationAccumulation lines in C. elegans and C. briggsae., Fabrice Besnard [et al.] . . . . . . . . 14

Polo-like kinase is required for nuclear envelope breakdown in early C. elegans em-bryo, Lisa Martino [et al.] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Control of autophagy during worm development via an intronic region, Jane Deuve [et al.] 16

Cell-to-cell communication modulates the immune response in Caenorhabditis elegans, SongHua Lee [et al.] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

C.elegans genomic platform of Marseille-Luminy, Jerome Belougne [et al.] . . . . . . . . 19

1

Purine metabolism a↵ects post-embryonic development, germline proliferation and mus-cle structure in C. elegans, Roxane Marsac [et al.] . . . . . . . . . . . . . . . . . . . . . . 20

Regulatory network in C. elegans innate immunity, Nishant Thakur [et al.] . . . . . . . 21

Targeted multicopy transgene integration in C. elegans, Iskra Katic [et al.] . . . . . . . . 22

Comparison of ivermectin and moxidectin resistance profiles in the nematode Caenorhab-ditis elegans, Cecile Menez [et al.] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Characterization of nematode-infecting microsporidia and natural variation in sensitivityof Caenorhabditis nematodes to microsporidia, Gaotian Zhang [et al.] . . . . . . . . . . . 24

Quantitative Analysis of the Polarization mechanism of a field of Neuronal Precursors inC. elegans, Shilpa Kaur [et al.] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Analysis of chromatin factors involved in the initiation and maintenance of neuronaldi↵erentiation programs, Guillaume Bordet [et al.] . . . . . . . . . . . . . . . . . . . . . 26

Host pathogen interactions in C. elegans, Jean-Christophe Lone [et al.] . . . . . . . . . . 27

Cellular innovations at the origin of pseudogamy in nematodes, Manon Grosmaire [et al.] 28

How cellular plasticity promoted and controlled an organism?, Thomas Le Gal [et al.] . 29

The SET-2/SET1 histone H3K4 methyltransferase maintains genome stability in theCaenorhabditis elegans germline, Marion Herbette [et al.] . . . . . . . . . . . . . . . . . 30

Mechanosensing in C. elegans embryogenesis: Hunting for a putative mechanosensor, ShashiKumar Suman [et al.] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Identification of novel regulators of GABAergic synaptogenesis in the nematode Caenorhab-ditis elegans., Marine Gueydan [et al.] . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Micro-movements of the mitotic spindle poles reveal cell division mechanics., BenjaminMercat [et al.] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

The C. elegans K cell as a new model to study cellular potential, asymmetric cell divisionand cell type conversion, Christelle Gally [et al.] . . . . . . . . . . . . . . . . . . . . . . 34

DRP-1, AIF and mTOR : a link between mitochondria morphology and muscle degen-eration in C. elegans ?, Charlotte Scholtes [et al.] . . . . . . . . . . . . . . . . . . . . . . 35

Is unc-70/�-spectrin a functional regulator of the neuronal potassium channel unc-58?, Philippe Tardy [et al.] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

The role of sel-10 in transdi↵erentiation, Cecile Delance [et al.] . . . . . . . . . . . . . . 37

2

Cryptic evolution behind a conserved asymmetric embryonic division in nematodes, MarieDelattre [et al.] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

List of participants 38

Author Index 42

3

KEYNOTE LECTURE

Into the unknome: high throughputgenetics and novel neural functions

Mario De Bono

MRC Laboratory of Molecular Biology,

Cambridge, UK.

4

The GABAergic system: not a closed chapter.

Marie Gendrel ⇤ 1,2, Emily Atlas 2, Oliver Hobert† 1,2

1 Howard Hughes Medical Institute (HHMI) – New York, United States2 Columbia University, Department of Biochemistry and Molecular Biophysics – New York, United States

Gamma-aminobutyric acid (GABA) is the major inhibitory neurotransmitter in the vertebratebrain, and dysfunction of GABAergic neurons can have profound pathological implications. In C.elegans, based on promoter fusion analysis, 26 neurons are known to express conserved GABAergic ter-minal di↵erentiation genes, such as the enzyme-producing GABA (GAD/unc-25 ), the GABA-specificvesicular transporter (VGAT/unc-47 ) and the protein that targets VGAT to the synaptic membrane (aLAMP-like protein/unc-46 ). Twenty-five of these worm GABAergic neurons are motoneurons and areinvolved in (i) head movements (4 RMEs), (ii) defecation (AVL and DVB), (iii) locomotion (19 D-type).Only one neuron, RIS, is an interneuron, like the dominant type of GABA neurons in vertebrates.Yet, in addition to the 26 classic GABA neurons, we detected by immunostaining GABA in the headmesodermal cell (hmc), ALA, RIBL/R and four other pairs of neurons whose identification is still inprogress. Using fosmid recombinering and CRISPR technology, we are mapping where the GABAer-gic terminal di↵erentiation genes are expressed in order to get a more comprehensive picture of theGABAergic system.

In parallel, we have a better understanding of how the di↵erentiation of the 26 classic GABAergicneurons is controlled. As published, it is known that UNC-30, a Pitx2 ortholog, is required for ex-pression of GABA terminal di↵erentiation genes in the D-type neurons. It is currently unknown whatthe terminal selectors for the other GABAergic neurons are. Through a candidate gene approach, weconfirmed with anti-GABA immunostaining that LIM-6 -a LIM homeobox transcription factor- controlsRIS, AVL and DVB fate. In addition, we generated a null allele of nhr-67 –a Tailless/TLX ortholog–and using anti-GABA immunostaining and marker analysis, we concluded that NHR-67 is involvedin RIS, AVL and RMEs terminal di↵erentiation, suggesting that NHR-67 and LIM-6 act together tocontrol RIS and AVL GABAergic fate. We also confirmed that CEH-10 is involved in RME terminaldi↵erentiation. Moreover, after an EMS mutagenenesis screen, we found that TAB-1, a homeodomaintranscription factor, is involved in RMEL/R GABAergic fate, suggesting that NHR-67, CEH-10 andTAB-1 work together to control RME fate. In parallel, we are currently investigating in DVB fate therole of EGL-38 - a Pax2/5/8 family member - and in D-type fate the role of ELT-1 – a GATA liketranscription factor.Together, these results will give us an updated picture of GABA neuron identification and development.

⇤Speaker

†Corresponding author: or38@columbia.edu

5

Identification of a transcription factor asdeterminant of muscle aging in Caenorhabditis

elegans

Adeline Mergoud Dit Lamarche ⇤ 1, Laurent Molin 1, Kathrin Gieseler 1,Jean-Louis Bessereau 1, Florence Solari 1

1 Centre de genetique et de physiologie moleculaire et cellulaire (CGphiMC) – CNRS : UMR5534, UniversiteClaude Bernard - Lyon I (UCBL) – UNIVERSITE CLAUDE BERNARD LYON 1 Batiment Gregor Mendel 16

rue Raphael Dubois 69622 VILLEURBANNE CEDEX, France

Aging is accompanied by a progressive loss of muscle mass and function termed sarcopenia. Inhuman, sarcopenia is responsible for a decrease in mobility, leading to a reduction in the quality of life.Epidemiological studies further suggest that skeletal muscle aging is also a risk factor for the devel-opment of several age-related diseases such as diabetes, cancer, Alzheimer’s disease, and Parkinson’sdisease.Several cell autonomous mechanisms have been proposed to be involved in muscle aging including mi-tochondria default [1], apoptosis [2] and alteration of muscle protein turnover [3]. However, those datahave been essentially obtained in models of experimentally induced muscle atrophy. Thus the questionof their importance and kinetic in the context of physiological aging remains unanswered. We are usingC. elegans to identify genetic pathways involved in muscle aging. Previous studies have shown thatworms exhibit loss of mobility [4], myosin filament disorganization and change in muscle nuclei shapewith age [5]. More recently, the Xu laboratory reported a functional decline of motor neurons thatprecedes alteration of muscle contraction [6]. However those studies did not allowed to identify genuinemuscle biomarker of sarcopenia that could be used to screen for genetic modifiers of sarcopenia. Forthis purpose, we first aimed to characterize the time course of cellular and molecular changes that takeplace during muscle aging.

We have shown that muscle aging is firstly characterized by a decrease in the expression of somebut not all muscle genes, followed by a change in mitochondria morphology and an impairment ofmuscular proteostasis. As the decrease of muscle genes expression is the earliest event, we hypothesizedthat it may play a causal role in sarcopenia. Further genetic, cellular and molecular investigationsallowed us to identify a transcription factor, which modulates di↵erent biomarkers of muscle aging andwhich function may be conserved in mammals.

1. Romanello V et al. EMBO J. 2010;29: 1774–1785. doi:10.1038/emboj.2010.602. Marzetti E et al. Gerontology. 2012;58: 99–106. doi:10.1159/0003300643. Masiero E et al. Autophagy. 2010;6: 307–309.4. Huang C et al. Proc Natl Acad Sci U S A. 2004;101: 8084–8089. doi:10.1073/pnas.04008481015. Herndon LA et al. Nature. 2002;419: 808–814. doi:10.1038/nature011356. Liu J et al. Cell Metab. 2013;18. doi:10.1016/j.cmet.2013.08.007

⇤Speaker

6

A streamlined protocol to facilitateCRISPR/Cas9 genome engineering using a

highly e�ciency sgRNA and an easilyselectable phenotype

Claire Lecroisey 1, Sonia El Mouridi ⇤ 1, Philippe Tardy 1, Melissa Zouak 1,Thomas Boulin† 1

1 Institut NeuroMyoGene (INMG) – Universite Claude Bernard-Lyon I - UCBL (FRANCE) – 8 RUERAPHAEL DUBOIS, 69100 Villeurbanne, France

Current CRISPR/Cas9 genome engineering strategies enable the directed modification of the en-tire C. elegans genome to introduce point mutations, generate knock-out mutants and insert codingsequences for epitope or fluorescent tags. Three practical aspects can complicate CRISPR experiments.First, the e�ciency of any given sgRNA (single guide RNA) cannot be reliably predicted. Second,the detection of animals the genome of which has been modified can be very challenging or timeconsuming in the absence of a clearly visible or selectable phenotype. Third, the sgRNA target sitemust be ”inactivated” following CRISPR-directed editing to avoid further double-strand break events.This often requires the introduction of silent mutations (e.g. in the Protospacer Adjacent Motif, PAM).

We describe here a strategy that attempts to address and circumvent these complications. First,we use CRISPR/Cas9 editing to transplant the protospacer sequence of a highly e�cient C. eleganssgRNA into a gene or close to a genomic region of interest. We have chosen an sgRNA targeting dpy-10gene (Arribere et al. 2014) because (i) it generates genome edits at comparatively high frequency and(ii) because F1 progeny carrying genome edits can be easily identified based on dominant phenotypes(Dpy or Dpy/Rol) caused by the dpy-10(cn64) mutation.

Next, we demonstrate that the heterologous site (aka. d10 site) can be cleaved at the same timeas the dpy-10 gene. Therefore, injected P0 animals and F1 progeny in which CRISPR events haveoccurred can be easily selected based on the dominant dpy-10 phenotypes (”marked” F1 worms). Thisdrastically reduces the number of animals to be tested by PCR, visual inspection or phenotypic analysis.

Finally, using the d10 -engineered strain, we are no longer required to introduce mutations in endoge-nous PAM sites or otherwise disrupt the genome sequence close to the targeted region when insertingpoint mutations or integrating specific DNA sequences.

So far, we have been able to reliably engineer four di↵erent loci and rapidly introduce multiple flu-orescent genes with minimal work. Using our strategy, gene edits are identified in 2 to 8.5 % of markedF1 worms. We have also used the same d10 -engineered strains to generate large and precise deletionsin two genes.

⇤Speaker

†Corresponding author: thomas.boulin@univ-lyon1.fr

7

A word from our sponsors

8

Characterization of the SET1/MLL complex inC. elegans

Flore Beurton⇤ 1, Cecile Bedet ⇤ 1, Matthieu Caron ⇤ 1, Francesca Palladino ⇤ †1

1 Laboratory of Molecular and Cellular Biology – Ecole Normale Superieure - Lyon – 46 allee d’italie 69007Lyon, France

Methylation of histone H3 Lys4 (H3K4me) is associated with active transcription in all species, andis catalyzed by highly conserved multiprotein complexes known as Compass in yeast or SET1/MLLin mammals. Work from several labs using both yeast and mammalian cells has led to a detailed de-scription of the SET1/MLL complexes. Biochemical analysis has shown that the H3K4 HMT activityof SET1/MLL proteins relies on protein-protein interactions within large multisubunit complexes thatinclude three core components: RbBP5, Ash2L, and WDR5. However, it remains unclear how thecomposition and specificity of these complexes varies between cell types and during development. Wethen decided to study the function of individual subunits of the complex in a developmental context.We have previously shown that SET-2, the sole SET1 homologue in C. elegans, and ASH-2, anothermember of the SET1/MLL complex play di↵erent roles in H3K4me during development. We have alsoshown an interaction between SET-2 and WDR-5.1 in embryos, but the full composition of the H3K4HMT complex in vivo is unknown. In order to better understand the regulation of H3K4me, we havedecided to develop a proteomic approach to identify SET-2/WDR-5.1 molecular partners.Preliminary attempts to immunoprecipitate a functional SET-2::HA tagged protein generated by CRISPR-Cas9 have failed. As an alternative strategy, we used animals expressing a WDR-5.1::HA protein toimmunoprecipitate the complex in embryos extracts and its composition will be analyzed by massspectrometry. Interesting partners will then be characterized using both genetic and biochemical ap-proaches.

⇤Speaker

†Corresponding author: francesca.palladino@ens-lyon.fr

9

Dissecting a worm killer

Le He ⇤ 1, Kevin Lebrigand 2, Nathalie Pujol 1, Pascal Barbry 2, JonathanEwbank† 1

1 Centre d’Immunologie de Marseille - Luminy (CIML) – Universite de la Mediterranee - Aix-Marseille II,CNRS : UMR7280, Inserm : U1104 – Parc scientifique et technologique de Luminy - 163, avenue de Luminy -

Case 906 - 13288 Marseille cedex 09, France2 Institut de pharmacologie moleculaire et cellulaire (IPMC) – CNRS : UMR7275, Universite Nice Sophia

Antipolis (UNS) – CNRS-IPMC 660 Route des lucioles 06560 VALBONNE, France

We have studied intensively the infection of C. elegans by Drechmeria coniospora (see Labed &Pujol (2012), Journal of Invasive Fungal Infections). We have recently initiated a project to dissect themolecular and cellular basis of D. coniospora’s capacity to infect worms and resist host immunity.As a first step, in collaboration with the Genoscope, we undertook the sequencing of the D. coniosporagenome. Combining di↵erent data, we have assembled a draft genome of 33 Mb on 9 chromosomes,and predicted 8,000 coding genes. On the basis of their sequence, more than half are associated withPfam & GO terms.

With the genome sequence in hand, we are taking 2 approaches to identify virulence genes: com-parative genomics and biochemistry:Sequence analyses revealed the presence of many genes potentially encoding virulence factors. As an ex-ample, the gene g3895, corresponding to a Saposin A type domain (PF02199) with a secretion peptide,was clearly acquired by horizontal gene transfer. Saposins are host defence proteins. In vertebrates,they are synthesized as proproteins, with the active saposin B domain inhibited by the regulatorysaposin A domain. There are 26 saposin B domain containing proteins in C. elegans. We speculatethat Drechmeria’s Saposin A protein may act as an inhibitor of nematode saposin B-containing proteinsand thus interfere directly with host defense. A reporter strain showed that g3895 is strongly expresson spores before attachment to the worm’s cuticle and on hyphae as they exit infected worms. Furtherstudy is in process.To identify proteins secreted from the fungal pathogen into the host epidermal cells, a biotin-streptavidinbased method was used. By locally expressing ascorbate peroxidase in the worm epidermis (usingstrains generously provided by Aaron Reinke and Emily Troemel), only the proteins present becomebiotinylated. The biotinylated proteins have been purified with streptavidin beads and subject to massspectrometry analysis. Preliminary results have allowed the identification of several fungal proteins,potentially secreted into the worm cells during infection. We now plan to characterize the function ofthese putative virulence factors.

⇤Speaker

†Corresponding author: ewbank@ciml.univ-mrs.fr

10

Host response to fungal infection and woundingin C. elegans epidermis

Clara Ta↵oni ⇤ 1, Jonathan Ewbank 2, Didier Marguet 1, Nathalie Pujol† 3

1 Centre d’Immunologie de Marseille - Luminy (CIML) – Universite de la Mediterranee - Aix-Marseille II,CNRS : UMR7280, Inserm : U1104 – Parc scientifique et technologique de Luminy - 163, avenue de Luminy -

Case 906 - 13288 Marseille cedex 09, France2 Centre d’Immunologie de Marseille-Luminy, Marseille France (CIML) – Aix-Marseille Universite - AMU :

UM2, Inserm, CNRS : UMR7280 – 163 avenue de Luminy 13009 Marseille, France3 Centre d’Immunologie de Marseille-Luminy, Marseille France (CIML) – Aix-Marseille Universite - AMU :

UM2, Inserm : U1104, CNRS : UMR7280 – 163 avenue de Luminy 13009 Marseille, France

Sterile wounding or infection of Caenorhabditis elegans by the fungus D. coniospora leads to a rapidincrease in the transcription of antimicrobial peptide (AMP) genes in the epidermis. Performing severalgenetic screens, we have previously identified many of the players involved in this innate immune re-sponse 1. Recently, we have shown that the GPCR DCAR-1 and its ligand HPLA, a tyrosine derivativecan trigger this response 2, through the p38 MAPK pathway which in turn activates the STAT-liketranscription factor STA-2 and induces AMP expression. Because genetic inactivation of vesicle traf-ficking abrogates immune signalling 3, we are interested in monitoring the subcellular localization anddynamics of the known signalling proteins upon damage and in studying their role in modulating thehost immune response. Using a knock-in strain where the GPCR DCAR-1 is tagged with tomato orwith GFP, we observed an apical signal on the epidermal syncytium which is rapidly relocalized uponwounding. We are now characterizing this recruitment together with the behavior of other signallingproteins upon infection and wounding.

In a recent study it was proposed that the STAT-like TF STA-2 is physically associated with hemidesmo-somes, which anchor the cuticle and the muscle to the epidermis and could act as mechanosensor. Re-moving one apical component of the hemidesmosomes can release STA-2 and activate AMP expressionin the epidermis 4. We are investigating if this mechanosensory pathway could act in parallel to theDAMP/HPLA pathway to sense an infection in the worm.

Labed, S. & Pujol, N. The Journal of Invasive Fungal Infection 5, 110-117 (2011).Zugasti, O. et al. Nature Immunology 15, 833-838 (2014).Dierking, K. et al. Cell Host Microbe 9, 425-435 (2011).Zhang, Y. et al. Immunity 42, 309-320 (2015).

⇤Speaker

†Corresponding author: pujol@ciml.univ-mrs.fr

11

Composition, organization and mechanicalcontribution of C. elegans embryonic sheath to

embryonic integrity and elongation

Thanh Vuong-Brender ⇤† 1, Michel Labouesse‡ 1

1 Laboratoire de Biologie du Developpement (LBD) – CNRS : UMR7622, Universite Pierre et Marie Curie(UPMC) - Paris VI – bat. C-30, 7 Etage, bte.24 9 Quai Saint-Bernard 75252 PARIS CEDEX 05, France

During morphogenesis, the remodeling of apical epidermal structures like cytoskeleton and junc-tions has been well characterized. In contrast, little is known about the role and the remodeling ofapical extracellular matrix. The embryonic sheath wrapping around C. elegans embryo has been pro-posed to be the force-transmitting component during its elongation (Priess and Hirsch 1986). However,the composition of this extracellular layer is largely unknown and how it transmits actomyosin forcesis poorly understood. In an RNAi screen for transmembrane and secreted proteins a↵ecting embry-onic morphogenesis, we identified NOAH-1 and NOAH-2, two ZP (Zona Pellucida)-domain containingproteins essential for the embryos to complete elongation. We built endogenous reporters of theseproteins using CRISPR-CAS9 technique. Their localization at the apical epidermal surface and thein the extra-embryonic space suggested that they are embryonic sheath components. They showed aremarkable reorganization during late phase of the embryonic elongation (after 2-fold embryo stage)and this remodeling seemed to be promoted by muscle contractions. We found that these two proteins,together with other putative extracellular matrix proteins SYM-1, LET-4 and FBN-1, contribute to theembryonic integrity after 2-fold stage. To assess mechanical properties and tension on the embryonicsheath during elongation, we used laser nano-ablation. The results showed that this layer is either moreelastic or less viscous than the actin cortex. In lateral epidermal cells, the recoil of the sheath afterablation was dependent on actin cortex, implying that the sheath relays actomyosin forces. Our studieshelp to shed light on the importance of apical extracellular matrix and its interaction with other tissuesduring morphogenesis.

Priess, J. R. and D. I. Hirsh (1986). ”Caenorhabditis elegans morphogenesis: the role of the cytoskeletonin elongation of the embryo.” Dev Biol 117(1): 156-173.

⇤Speaker

†Corresponding author: thanh.vuong@upmc.fr

‡Corresponding author: michel.labouesse@upmc.fr

12

The anti-apoptotic CED-9/Bcl-2 proteinprotects against muscle degeneration in

Caenorhabditis elegans models for musculardystrophies

Mathieu Baritaud ⇤ 1, Marie-Christine Mariol 1, Edwige Martin 1, KathrinGieseler† 1

1 Centre de genetique et de physiologie moleculaire et cellulaire (CGphiMC) – CNRS : UMR5534, UniversiteClaude Bernard - Lyon I (UCBL) – UNIVERSITE CLAUDE BERNARD LYON 1 Batiment Gregor Mendel 16

rue Raphael Dubois 69622 VILLEURBANNE CEDEX, France

Muscular dystrophies are characterized by muscle weakness and degeneration induced by geneticmutations a↵ecting muscle structure or signaling components. The subcellular mechanisms of musculardystrophies are poorly understood and the development of treatments is challenging, in part due togreat variety of primary genetic defects.Using di↵erent Caenorhabditis elegans models that mimic human muscular dystrophies such as Duchenneand Becker dystrophies, Limb-Girdle, Emery- Dreifuss or congenital muscular dystrophy, we found thata gain of function mutation of the anti-apoptotic protein CED-9, ortholog of mammalian B cell lym-phoma 2 (Bcl-2), strongly reduced muscle degeneration.

To investigate the molecular pathways, we analyzed the impact of mutations a↵ecting keys e↵ectors ofprogrammed cell death (PCD) mechanisms such as CED-3/caspase-3, CED-4/Apaf-1, CED-9/Bcl-2,CED-13 and EGL-1 (two orthologs of pro-apoptotic Bcl-2 protein family) on muscle degeneration inthe Duchenne Muscular Dystrophy (DMD) C. elegans model. We evaluated di↵erent features of musclecell death : destruction of actin filament network, nuclei loss, mitochondrial stress by measuring ROSproduction with Hyper transgene; and the state of mitochondrial network. Using CRISPR mediatedgenome engineering we currently determine domains of protein interactions between CED-9 and thedi↵erent PCD e↵ectors so as to reveal new PCD actors involved in muscle degeneration through theinvestigation of CED-9 partners.

Finally, by deciphering the role of the PCD machinery and the anti-apoptotic CED-9 protein in di↵er-ent C. elegans models for muscular dystrophies, we aim at identifying common molecular pathways toreduce, stop or reverse muscle degeneration in muscular dystrophies.

⇤Speaker

†Corresponding author: kathrin.gieseler@univ-lyon1.fr

13

Mapping and identifying mutations causingrapid evolution in a cell fate using MutationAccumulation lines in C. elegans and C.

briggsae.

Fabrice Besnard ⇤ 1, Marie-Anne Felix 1

1 Institut de Biologie de l’Ecole Normale Superieure (IBENS) – Institut de Biologie de l’Ecole NormaleSuperieure – 46, rue d’Ulm 75005 PARIS, France

How mutations a↵ect phenotypes is a crucial question in both developmental biology and evolu-tion. In Caenorhabditis nematodes, we use the paradigmatic model of vulva precursor cells (VPC)development to address why di↵erent cell lineages do not show equal robustness to mutations. Indeed,our lab recently showed that one VPC, P3.p, has a much higher mutational variance than the fiveother vulval precursors (Braendle, Baer & Felix, PLoS Gen. 2010), by analyzing phenotypes of a set ofMutation accumulation Lines (MALs) of C. elegans and C. briggsae. In wild-type worms, P3.p alreadystands out by having a stochastic cell fate: it can either divide once or fuse directly with the epidermiswithout dividing. In an isogenic population of worms, the division frequency of P3.p is reproduciblefor a genotype, in a given environment. In MALs, P3.p division frequency is the fastest evolving vulvatrait. Interestingly, this result mirrors the real evolution observed within the Caenorhabdtitis genus.Although the gene regulatory network controlling vulva cell specification is well-known, we cannot ex-plain such high mutational variance of P3.p: is it due to hotspots of mutations specifically involvedin P3.p fate determination? To a specific genetic architecture? Or to a particular developmental con-text? We thus selected 6 MALs produced by 250-generations of single-worm bottlenecks (two in C.briggsae, four in C. elegans) displaying marked evolution of P3.p division frequency and we seek toidentify the molecular nature of the mutations causing this evolution. By whole-genome re-sequencing,we thoroughly analyzed de novo mutations in each line. First, we found interesting features such asoccurrences of large (several kbp) deletions or di↵erences between C. elegans and C. briggsae muta-tion rates, in line with di↵erences in mutational variance measured a few years ago between those twospecies. Second, we mapped and identify candidate mutations in 5 lines by using a strategy based onserial parallel backcrosses and direct genotyping by pyrosequencing. To our knowledge, this is the firstreport of the identification of mutations responsible for the evolution of a phenotype in MALs. We arecurrently validating those mutations, especially by reproducing the exact mutation by CRISPR-Cas9genome editing. The diversity of the genes a↵ected (members of the Wnt signaling pathway; of thetranscriptional repressor mediator complex, of translational activation and genes of unknown functions)strongly suggests that the high mutational variance of P3.p is due to a wide mutational target size.These results also broaden our view of the genes involved in the fine-tuning of VPC cell fate.

⇤Speaker

14

Polo-like kinase is required for nuclear envelopebreakdown in early C. elegans embryo

Lisa Martino ⇤ 1, Lionel Pintard 1

1 Institut Jacques Monod (IJM) – UMR7592, Paris-Diderot University - CNRS – 15 rue helene brion, 75013PARIS, France

⇤Speaker

15

Control of autophagy during wormdevelopment via an intronic region

Jane Deuve ⇤ 1, Jorge Merlet 1, Charlene Perrois 1, Sara Al Rawi 1, VincentGaly 1

1 C. elegans Heredity and Development (CelHD) – Universite Paris VI - Pierre et Marie Curie – UMR7622 -IBPS University Pierre and Marie Curie - CNRS - Paris- France, France

In C. elegans autophagy, the respective functions of the two actors LGG-1 and LGG-2 are starting tobe unravelled. Despite the fact that LGG-2 (the C. elegans homolog of mammalian LC3) is thought tobe secondary for autophagy to be achieved (the two reported null mutants have a normal development)we describe a new lgg-2 lethal mutant that sheds light on the importance of LGG-2. We have shownthat in lgg-2 first intron stands a Caenorhabditis conserved DNA sequence crucial for controlling lgg-2transcription in a tissue-dependant manner. In the mutant lacking this region, LGG-2 is abnormally upregulated in the muscle attachment structure, and the therefore up regulated autophagy is correlatedwith a sleeping bag phenotype, the mutant worms being unable to escape their molt. We propose acatalytic function for LGG-2, able to fine tune autophagy during normal development.

⇤Speaker

16

Poster session

17

P1 – Cell-to-cell communication modulates theimmune response in Caenorhabditis elegans

Song Hua Lee ⇤ 1, Annie Boned 1, Shizue Omi 1, Jonathan Ewbank† 1, NathaliePujol‡ 1

1 Centre d’Immunologie de Marseille-Luminy, Marseille France (CIML) – Aix-Marseille Universite - AMU :UM2, Inserm : U1104, CNRS : UMR7280 – 163 avenue de Luminy 13009 Marseille, France

The C. elegans epidermis is a powerful model for understanding the fundamental innate defencestrategies of epithelial tissues. Upon invasion by the fungal pathogen Drechmeria coniospora or physicalinjury, C. elegans mounts an innate immune response, upregulating the expression of antimicrobial pep-tide genes in the epidermis (1). Increasing evidence suggests that cell-cell communication is essentialto generate coordinated protective responses (reviewed in 2). For instance, Kawli and Tan demon-strated that neuroendocrine signals modulate the expression of intestinal defence genes through thedaf-2/daf-16 insulin-signalling pathway (3), whilst neuronally produced TGF-ß regulates expression ofantimicrobial peptides in the epidermis (4). The expression of one insulin-like peptide gene, ins-11,that encodes a DAF-2 antagonist (5) is induced upon D. coniospora infection (6). We have now foundthat infection induces ins-11 expression in the epidermis and that this is dependent on the p38 MAPKpathway. Through comparative genomic analyses, we have defined a list of D. coniospora infection-response genes that are potential targets of DAF-16 in the intestine. We are currently assaying thesegenes to determine whether their expression is dependent upon ins-11. Defining such genes will thenallow us to take a genetic approach to dissect the mechanisms underlying cross-tissue signalling and tostudy how a master tissue is capable of sensing perturbations within its own cellular environment andsubsequently mediating organism-wide protection on other tissues upon infection or physical wounding.

1. Pujol et al., Current Biology 18: 481-489, 20082. Ewbank and Pujol, Current Opinion in Immunology 38:1-7, 20163. Kawli and Tan, Nature Immunology 9: 1415-1424, 20084. Zugasti and Ewbank, Nature Immunology 10: 249-256, 20095. Kawano et al., Bioscience, Biotechnology and Biochemistry 70: 3084-3087, 20066. Engelmann et al., PLoS ONE 6(5): e19055, 2011

⇤Speaker

†Corresponding author: ewbank@ciml.univ-mrs.fr

‡Corresponding author: pujol@ciml.univ-mrs.fr

18

P2 – C.elegans genomic platform ofMarseille-Luminy

Jerome Belougne ⇤† 1, Celine Caillard⇤ 2

1 Centre d’Immunologie de Marseille-Luminy (CIML) – Inserm : U1104 – Centre d’Immunologie deMarseille-Luminy Parc Scientifique Technologique de Luminy, Case 906, 13288 Marseille cedex 09, FRANCE,

France2 Centre d’Immunologie de Marseille-Luminy (CIML) – CNRS : UMR7280 – Centre d’Immunologie de

Marseille-Luminy Parc Scientifique Technologique de Luminy, Case 906, 13288 Marseille cedex 09, FRANCE,France

Custom developments to satisfy user needs enable the C. elegans platform of Marseille-Luminy toimplement specific solutions for high-throughput genetic and genomic studies. Based around the CO-PAS worm sorter, the platform is able to perform the cloning of small populations, from 96 to 96-wellsplates, as well as large screens, such as genome-wide RNAi and F3 clonal screens (EMS).The platform was part of the NEMAGENETAG MOS Project, generating 55,000 Mos1 transposoninsertion lines from several hundred thousand clonal lines cultured for 6 generations. It has carried outgenome-wide RNAi screens based on the Ahringer & Vidal libraries (e.g. 140,000 samples analysed ina screen for genes involved in anti-fungal innate immunity).

Recently, we have associated our TECAN robot with a Leica DMS300 macroscope, together withdedicated software (produced in collaboration with Dominique Brandli, IBDM), and we are now ableto perform automated lifespan monitoring on di↵erent strains of interest. In principal, we can monitorthe survival of more than 100 strains at a time.

Lastly, in collaboration with Igor Ozerov, (CINaM), we are attempting to develop an alternative to thetime-consuming micro-injection method for the generation of transgenic strains.

⇤Speaker

†Corresponding author: belougne@ciml.univ-mrs.fr

19

P3 – Purine metabolism a↵ects post-embryonicdevelopment, germline proliferation and muscle

structure in C. elegans

Roxane Marsac 1, Christelle Saint-Marc 1, Bertrand Daignan-Fornier 1,Jose-Eduardo Gomes ⇤† 1

1 Institut de biochimie et genetique cellulaires (IBGC) – CNRS : UMR5095, Universite de Bordeaux (Bordeaux,France) – 1 Rue Camille Saint-Saens 33077 BORDEAUX CEDEX, France

Living organisms regulate their metabolism in response to their own physiological status and tothe surrounding environment. Biosynthetic pathways have been extensively characterized mostly inunicellular organisms, much less is known about the relationship between metabolism and other cellu-lar/organismal functions in metazoans (e.g. development, cell cycle, behavior). Purine biosynthesis ishighly conserved from bacteria to humans, and deficiencies on specific enzymes of the pathway causesevere human diseases. We developed a C. elegans model to study pathologies associated with purinemetabolism. We verified functional conservation of crucial enzymes ADSL, PPAT and ATIC in C. ele-gans, and performed a phenotypic analysis of mutants deficient for these enzymes. We observed defectson post embryonic development, germline proliferation, locomotion behavior, muscle structure, fertilityand lifespan. For the most part these phenotypes are separable; our results indicate that accumulationof intermediate metabolites SAICAR or AICAR causes shortened life span (SAICAR), reduced fertil-ity and abnormal locomotion (AICAR). Deficiency in ADSL enzyme causes abnormal post-embryonicdevelopment, defects on muscle structure and hinders germline proliferation. Our work allowed toestablish a workable basis to analyze purine metabolism in the animal model organism C. elegans.

⇤Speaker

†Corresponding author: jose-eduardo.gomes@u-bordeaux.fr

20

P4 – Regulatory network in C. elegans innateimmunity

Nishant Thakur ⇤† 1, Maxime Bulle 1, Annie Boned 1, Shizue Omi 1, NathaliePujol 1, Jonathan Ewbank‡ 1

1 Centre d’Immunologie de Marseille-Luminy, Marseille France (CIML) – Aix-Marseille Universite - AMU :UM2, Inserm, CNRS : UMR7280 – 163 avenue de Luminy 13009 Marseille, France

Our lab is working on innate immunity using the nematode C. elegans as a model host. Uponfungal infection C. elegans up-regulates the expression of many antimicrobial peptide (AMP) genes.These AMPs provide direct protection against pathogen attack. We are building an integrated generegulatory network for C. elegans to represent the induction of these AMP genes upon infection. Toachieve this, we integrate in-house and public data from various techniques, including genome-wideRNAi screens, RNA-seq, small RNA-seq (mainly miRNA) and Chip-seq. Firstly, to identify the keygenes of the network, our lab carried out a genome wide RNAi screen and identified 360 RNAi clonesthat block the immune response. For these 360 RNAi clones, we identified 676 target genes using”CloneMapper”; http://bioinformatics.lif.univ-mrs.fr/RNAiMap/. To explore the dynamics of geneexpression upon infection, we ran RNASeq analyses at 2, 4, 6 and 8 hours post infection and identifiedthe clusters of Di↵erential Expressed Genes (DEG) at di↵erent time point post infection. To identifythe potential regulators of these cluster of DEGs, we are analyzing modENCODE chipseq data for 92TFs, mainly using RSAT tools developed by our collaborator Jacques van Helden and looking for theenrichment of DEGs in potential targets of these TFs. We are validating the targets of di↵erent TFs byusing a medium-throughput Fluidigm-based approach. Our final objective is to integrate informationfrom these di↵erent datasets with protein-protein interaction data to build a robust regulatory networkthat explains the regulation of these defense genes upon infection.

⇤Speaker

†Corresponding author: thakur@ciml.univ-mrs.fr

‡Corresponding author: ewbank@ciml.univ-mrs.fr

21

P5 – Targeted multicopy transgene integrationin C. elegans

Iskra Katic ⇤† 1, Gert-Jan Hendriks 1, Lan Xu 1, Helge Grosshans‡ 1

1 Friedrich Miescher Institute for Biomedical Research (FMI) – Basel, Switzerland

The ability to heritably overexpress transgenes is important for analysis of gene function. In C.elegans, however, the existing methods to control copy number and insertion sites of multicopy trans-genes are crude at best. We have shown that DNA repair not based on homologous recombination canbe harnessed to insert single-copy transgenes into precise genomic sites. We now extend this method tointegration of complex transgenes into the well characterized locus ttTi5605 using the CRISPR/Cas9system and will present the technique that resulted in successful integrations.

⇤Speaker

†Corresponding author: iskra.katic@fmi.ch

‡Corresponding author: helge.grosshans@fmi.ch

22

P6 – Comparison of ivermectin and moxidectinresistance profiles in the nematode

Caenorhabditis elegans

Cecile Menez ⇤ 1, Dalia Kansoh , Jean-Francois Sutra 1, Anne Lespine 1

1 ToxAlim (ToxAlim) – Institut national de la recherche agronomique (INRA) : UMR1331 – 180 chemin deTournefeuille - BP 93173 31 027 Toulouse Cedex 3, France

The anthelmintic macrocyclic lactones ivermectin (IVM) and moxidectin (MOX) are the mostwidely administrated drugs to treat nematode infections. Their widespread use has led to the emergenceof resistance to these two drugs. Although they have identical modes of action, di↵erences in termsof pharmacokinetics, toxicity and selection for drug resistance have been reported between IVM andMOX. The objective of this study was to investigate and compare di↵erences between IVM and MOXregarding drug selection and development of acquired tolerance against the drug in the model nematodeCaenorhabditis elegans. For this purpose, we have evaluated the ability of C. elegans to become tolerantto MOX through stepwise exposure to increasing doses of drug. C. elegans developed resistance toMOX but, after 40 weeks, worms were able to grow only on 5.7 nM of MOX, which was twice lowerthan the IVM concentration on which IVM-selected worms were able to survive. Then, sensitivityto IVM, MOX and eprinomectin (EPR) of the MOX-selected worms was determined and comparedwith the wild-type N2 Bristol and an IVM-selected strains with a larval development assay. IVM andMOX displayed the same e�cacy in wild-type strain (IC50 of 1.69±0.30 and 1.77±0.25 nM, for IVMand MOX, respectively). Interestingly, selection with either IVM or MOX lead to targeted resistanceagainst the drug used for the selection associated with cross-resistance to other MLs (with highere�ciency of MOX compared to the IVM). Importantly, MOX was more potent in both IVM-selected(12.43±1.65 and 3.06±0.51 nM, for IVM and MOX, respectively) and MOX-selected (12.46±0.96 and4.24±0.58 nM, for IVM and MOX, respectively) strains, showing that the loss of potency observedwith IVM after MLs selection has significantly less impact on the potency of MOX. This order ofpotency was also observed in an LDA with Haemonchus contortus resistant isolate. In addition, therewas a significant increase in the transcriptional profiles of a number of ABC transporters and CYPenzymes, while coadministration of verapamil with IVM and MOX potentiated sensitivity to the drug.The results suggest that similar mechanisms are involved in the development of tolerance to MLs aftereither IVM or MOX selection and that detoxification systems play a partial role in the MLs sensitivityin C. elegans resistant strains. The similarities with parasites are of concern and highlight the use ofdrug-selected strains of C. elegans, a model organism for research on parasitic nematodes.

⇤Speaker

23

P7 – Characterization of nematode-infectingmicrosporidia and natural variation in

sensitivity of Caenorhabditis nematodes tomicrosporidia

Gaotian Zhang ⇤ , Marie-Anne Felix† 1

1 Institut de Biologie de l’Ecole Normal Superieure (IBENS) – Ecole Normale Superieure de Paris - ENS Paris –46 rue d’Ulm 75230 Cedex 05 Paris, France

The microsporidian Nematocida parisii is the first characterized intracellular pathogen of Caenorhab-ditis elegans; and a second Nematocida species, called N. sp. 1, was also reported from an Indian C.briggsae isolate (Troemel et al. 2008). In our lab we further established a collection of wild rhabditidnematodes suspected with microsporidian infection. Here, we characterize molecularly these wild mi-crosporidia and study their specificity of infection.First, the potentially infected rhabditid isolates were characterized using newly designed PCR primersspecific for 18S and �-tubulin genes of microsporidia. In addition to C. elegans, we found wild C.briggsae as natural host for N. parisii ; in addition to C. briggsae, we found C. elegans and C. remaneias natural hosts of N. sp. 1. We further found seven new microsporidian species. Four of them areclose to the Nematocida species in microsporidian clade II and preliminarily named N.-like sp. 2 ˜sp.5. The other three species, only found infecting Oscheius nematode, are very distant, and foundin microsporidian clade IV, that includes most human pathogens. They are closest to Orthosomellaoperophterae (with 18S), and thus preliminarily named Orthosomella-like sp.1 ˜ sp.3. Phylogeneticanalyses with the 18S and �-tubulin genes provide the same relationships of Nematocida spp. and theseven putative new microsporidia species.

Second, specificities of seven nematode-infecting microsporidia (N. parisii, N. sp. 1, N.-like sp. 2˜ sp. 3, and Orthosomella-like sp. 1 ˜ sp. 3.) were tested on four nematode species (C. elegans,C. briggsae, O. tipulae and O. sp. 3 ). N. parisii, N.-like sp. 2 only infect Caenorhabditis. To theinfection of N. sp. 1, Caenorhabditis are more sensitive than Oscheius. N.-like sp. 3 infects bothCaenorhabditis and Oscheius. Orthosomella-like spp. infect Oscheius spp., but not Caenorhabditis.O.-like sp. 2 infects both Oscheius spp., O.-like sp. 1 only infects Oscheius sp. 3, O.-like sp. 3 onlyinfects O. tipulae.Third, two transgenic C. elegans strains ERT54 jyIs8 [C17H1.6p::gfp; myo-2p::mCherry] and ERT72jyIs15 [F26F2.1p::gfp; myo-2::mCherry], which express a constitutive fluorescent Cherry marker andwill induce GFP upon infection with N. parisii (Bakowski et al. 2014), were used in infection tests.Our results show that N. parisii, N. sp. 1, N.-like sp. 2 and N.-like sp. 3 can infect ERT54 and ERT72,forming meronts and spores; N. sp. 1 does not induce the GFP reporter (or only rarely), while theother three induce it consistently, suggesting that C. elegans has a di↵erent transcriptional response tothe infection of N. sp. 1 than to other Nematocida spp..

⇤Speaker

†Corresponding author: felix@biologie.ens.fr

24

P8 – Quantitative Analysis of the Polarizationmechanism of a field of Neuronal Precursors in

C. elegans

Shilpa Kaur ⇤ 1, Pierre Lenne 1, Vincent Bertrand† 1

1 Institut de biologie du developpement de Marseille (IBDM) – CNRS : IFR138, Universite de la Mediterranee -Aix-Marseille II – Campus de Luminy case 907 13288 MARSEILLE CEDEX 09, France

Cell and tissue polarities are essential for the functions of animals and their misregulations areoften associated with pathologies. Several studies in animal models have identified molecules involvedin tissue polarization and suggest that gradients of extracellular signaling molecules are crucial in thisprocess. However how gradients of extracellular molecules can polarize fields of cells is not understood.One factor that limits our understanding of tissue polarization is the lack of quantitative data on thebehavior and interactions between the molecular players in polarization processes occurring in vivo.To better understand the process of tissue polarization we are using the field of neuronal precursorsof the C. elegans embryo as a model system. In C. elegans most of the neurons are generated duringneurulation by asymmetric divisions oriented along the antero-posterior axis. We have shown thatthese divisions are regulated by a particular Wnt/beta-catenin pathway and by using gain and loss offunction approaches we have identified a role for three Wnt ligands in the polarization of the neuronalprecursors before their division. We are currently using quantitative in vivo imaging methods to betterunderstand this polarization process.

⇤Speaker

†Corresponding author: vincent.bertrand@univ-amu.fr

25

P9 – Analysis of chromatin factors involved inthe initiation and maintenance of neuronal

di↵erentiation programs

Guillaume Bordet ⇤† 1, Carole Couillault 1, Vincent Bertrand‡ 1, Lilian Lanteri, Pauline Melenec , Amandine Palandri

1 Institut de biologie du developpement de Marseille (IBDM) – CNRS : IFR138, Inserm : IFR138, Universite dela Mediterranee - Aix-Marseille II – Campus de Luminy case 907 13288 MARSEILLE CEDEX 09, France

In both vertebrates and invertebrates, postmitotic neurons are often generated by asymmetricdivisions of neuronal progenitors such as neural stem cells. We have previously established that in C.elegans the asymmetric divisions of neuronal precursors are regulated by an asymmetric activation ofthe Wnt pathway. More recently we have identified, during a genetic screen, mutants in the chromatinregulator complex PRC1 that a↵ect the generation of some neurons by asymmetric divisions. They alsoa↵ect the maintenance of the expression of terminal di↵enrentiation genes important for the identityand functions of those neurons. We are currently investigating how these chromatin factors connectthe asymmetric division machinery to terminal di↵erentiation programs and how they strengthen themaintenance of those programs ?

⇤Speaker

†Corresponding author: guillaume.bordet@univ-amu.fr

‡Corresponding author: vincent.bertrand@univ-amu.fr

26

P10 – Host pathogen interactions in C. elegans

Jean-Christophe Lone ⇤ 1, Jonathan Ewbank 1, Nathalie Pujol† 1

1 Centre d’Immunologie de Marseille - Luminy (CIML) – Universite de la Mediterranee - Aix-Marseille II,CNRS : UMR7280, Inserm : U1104 – Parc scientifique et technologique de Luminy - 163, avenue de Luminy -

Case 906 - 13288 Marseille cedex 09, France

Infection provokes an immediate defense reaction in the host termed innate immunity. Certain mech-anisms of innate immunity are conserved throughout vertebrates and invertebrates. We are studyingthe innate immune response of a simple organism C. elegans to infection by a natural fungal pathogen.Through genetic and RNAi screens, we have defined several signaling pathways that lead to the activa-tion of defense genes in the infected tissue. We were able to show that infection provokes the conversionof tyrosine to hydroxyphenyllactic acid (HPLA) and this in turn activates the G-protein coupled re-ceptor DCAR-1 that acts upstream of a PKC-p38 MAPK pathway and the STAT-like transcriptionfactor STA-2. The level of HPLA in the nematode epidermis is also increased upon physical injuryor developmental alteration of the cuticle. Thus HPLA appears to be a damage-associated molecularpattern (DAMP), and DCAR-1 to be the first DAMP receptor identified in C. elegans (Pujol et al,CB 2008; Dierking et al., Cell Host & Mic. 2011; Zugasti et al., Nat. Imm 2014). Just how infectionleads to an increase in HPLA is, however, unknown. We propose to dissect the mechanism leadingto its production by doing a genetic screen in a developmental mutant, with a cuticle defect, whereina reporter inducible by infection is constitutively turned on, from the early larval stage. To avoidisolating mutants for components downstream of the GPCR, the strain used in the strain will express aconstitutively active Galpha protein (GPA-12) in the adult epidermis. Screening for mutants that blockreporter gene expression in larvae but not in adults will identify specifically genes acting upstream ofGPA-12 and hence potentially reveal the steps leading to the production of HPLA.

⇤Speaker

†Corresponding author: pujol@ciml.univ-mrs.fr

27

P11 – Cellular innovations at the origin ofpseudogamy in nematodes

Manon Grosmaire ⇤ 1, Caroline Launay ⇤ 1, Marie Delattre 1, Marie-Anne Felix2

1 Laboratoire de Biologie Moleculaire de la Cellule (LBMC) – CNRS : UMR5239, Universite Claude Bernard -Lyon I (UCBL), Ecole Normale Superieure (ENS) - Lyon – ENS de Lyon 46 allee d’Italie 69364 LYON Cedex

07, France2 Institut de Biologie de l’Ecole Normale Superieure (IBENS) – Ecole Normale Superieure de Paris - ENS Paris

– 46 rue d’Ulm 75230 Cedex 05 Paris, France

Pseudogamy is a mode of reproduction in which the fertilization of an oocyte by a sperm cell isnecessary even tough the male DNA does not contribute to the zygote genome in most embryos. Em-bryos in which the sperm DNA does not decondense give rise to 100% females, while the contributionof sperm DNA allow the production of rare males in the population (Nigon, 1942). Pseudogamy hasbeen described in several species of nematodes. It has been proposed that oocytes with incompletemeiosis will not utilize the male DNA, while oocytes undergoing the regular two steps of meiosis allowthe decondensation of the male DNA. These observations suggest that pseudogamy is the consequenceof a stochasticity in the progression through meiosis, accompanied by a control of the paternal DNA.We have recently identified several pseudogamous species within the Mesorhabditis genus. In orderto study the molecular and cellular innovations that have allowed the emergence of such paradoxicalreproductive strategy, we are establishing tools to develop a genetic approach in one of this strain. Wewill present our di↵erent strategies.Among the 20 new strains of the Mesorhabditis genus that have been collected, 6 have a classicmale/female mode of reproduction and 14 are pseudogamous. Sequencing of ITS, 18S and 28S al-lowed us to obtain a first phylogeny, indicating that pseudogamous species constitute a monophyleticgroup. Combined with genetic crosses and morphological description, we have so far identified at least8 independent pseudogamous species, and several strains per species.

We selected one pseudogamous strain isolated in Orsay, JU2817, as our reference strain. Two otherstrains (isolated in France or UK) belong to the same species and will serve as polymorphic strains forfurther genetic studies. In JU2817, 80% of oocyte display an incomplete meiosis and therefore only10% of males are present in the population at 20�C. The strain has been inbred for 10 generations andthe DNA and RNA are currently being prepared for genome and transcriptome sequencing. We arealso trying to establish the CRISPR/Cas9 technique in this strain.Evidences that environmental conditions can influence the sex ratio in pseudogamous species broughtus to further investigate the e↵ect of temperature on the sex ratio of JU2817. Our preliminary resultssuggest that the sex ratio and the fertilization e�cacy are both influenced by the size of the population,but not by the temperature.

⇤Speaker

28

P12 – How cellular plasticity promoted andcontrolled an organism?

Thomas Le Gal ⇤ 1, Arnaud Ahier 1, Sophie Jarriault 1

1 IGBMC – CNRS UMR 7104, Inserm U 964, UdS – 1 rue Laurent Fries / BP 10142 / 67404 Illkirch CEDEX,France

We are interested in the mechanisms allowing a cell to change its identity. For this, we use a naturaltransdi↵erentiation event where a rectal cell converts into a moto-neuron, in C. elegans. Work in thelab has shown that this cell type conversion involves first the erasure of the rectal identity, beforere-di↵erentiation into a moto-neuron. However this transient de-di↵erentiation is not coupled with areversal to a multi- or pluri-potent state. Further work has shown that a nuclear complex is necessaryfor the de-di↵erentiation step, and that its members are conserved pluripotency factors. Pluripotency isone important cellular property of early embryonic cells in mammals that allows these cells to give riseto a variety of di↵erentiated cells types, and ultimately to a functional organism. How is pluripotencyestablished and maintained has been the subject of intensive work in the last decades, but is stillnot fully understood. Landmark experiments by Yamanaka show that 4 transcription factors, oct3/4,sox-2, c-myc and klf4, are su�cient to turn specialised cells into pluripotent cells, called iPS cells. Inaddition, sox2 and oct4 are at the center of the so-called pluripotency network, including sall4 or mta1,which is necessary to maintain pluripotency. We have found that these same 4 factors are necessary topromote de-di↵erentiation in vivo, while not establishing pluripotency. We now are closely investigatinghow these factors function during the initial phases of transdi↵erentiation. Indeed Arnaud Ahier hasshown that ceh-6/oct4 and sox-2 can be required at successive steps of transdi↵erentiation, prior tothe initiation. To understand whether and what intrinsic properties of CEH-6/OCT4 and SOX-2 couldunderlie their ability to promote de-di↵erentiation but not pluripotency in the worm, as opposed to theirmammalian counterparts, Arnaud has examined CEH-6 and SOX-2 interaction surfaces in C. elegans.We are further trying to understand which domains of CEH-6/OCT4 and SOX-2 are important for thetransdi↵erentiation process as well as mapping the interaction pattern of ceh-6 and sox-2 with respectto their transcriptional activity, and will report on our latest findings at the meeting.

⇤Speaker

29

P13 – The SET-2/SET1 histone H3K4methyltransferase maintains genome stability in

the Caenorhabditis elegans germline

Marion Herbette ⇤ 1, Marine Mercier 2, Steve Garvis 1, Matthieu Caron 1,Francesca Palladino† 1, Valerie Robert‡ 1

1 Laboratory of Molecular and Cellular Biology – Ecole Normale Superieure - Lyon – 46 allee d’italie 69007Lyon, France

2 Centre de genetique et de physiologie moleculaire et cellulaire (CGphiMC) – CNRS : UMR5534, UniversiteClaude Bernard - Lyon I (UCBL) – UNIVERSITE CLAUDE BERNARD LYON 1 Batiment Gregor Mendel 16

rue Raphael Dubois 69622 VILLEURBANNE CEDEX, France

Histone H3 Lysine 4 methylation (H3K4me) is deposited by the conserved SET1/MLL familymethyltransferases. SET-2, one of the two SET1/MLL family members encoded by the C. elegansgenome, is required to catalyze both germline H3K4me2 and H3K4me3. In germlines missing SET-2,misexpression of germline and somatic genes is observed that correlates with loss of germline pluripo-tency and transdi↵erentiation of germ cells into somatic cell types (Robert, Mercier et al, 2014). Wewill present recent data showing that in addition to preserving germline identity, SET-2 and H3K4meare also required for genome stability in the C. elegans germline. We demonstrated that the absenceof SET-2 results in (i) a mutator phenotype, (ii) increased sensitivity to DNA damage inducing agentsand (iii) an accumulation of DNA double strand breaks (DSBs) and fragmented chromosomes followingexposure to ionizing radiation (IR). However, the DNA damage response pathway that coordinates cellcycle arrest, DNA damage repair and apoptosis is still functional in the absence of SET-2. Based onthese observations, we hypothesize that the absence of H3K4 methylation in the germline might a↵ectthe respective use of conservative homologous recombination and error-prone end-joining pathways torepair DNA DSBs in the C. elegans germline. We will present genome-wide sequencing and geneticapproaches that we are now using to test this hypothesis.

⇤Speaker

†Corresponding author: francesca.palladino@ens-lyon.fr

‡Corresponding author: valerie.robert@ens-lyon.fr

30

P14 – Mechanosensing in C. elegans

embryogenesis: Hunting for a putativemechanosensor

Shashi Kumar Suman ⇤ 1, Michel Labouesse† 1

1 Institut de Biologie Paris-Seine – Universite Pierre et Marie Curie [UPMC] - Paris VI – Biologie duDeveloppement, UMR7622, Institut de Biologie Paris-Seine, UPMC, 9 quai Saint Bernard, 75252 Paris, France

Mechanosensing refers to a process whereby mechanical inputs are sensed and transduced as chemi-cal or electrical signal to initiate or accelerate a downstream pathway. Many important biological eventsare mediated by this process including tissue di↵erentiation, morphogenesis and also in pathophysio-logical conditions such as tumor progression, but their mechanisms at a molecular level remain poorlyunderstood. Mechanotransduction signaling in vivo can be triggered by body-wall muscle contractions(elongating C. elegans embryos), cell shape changes (Drosophila embryos), hydrodynamic forces (ven-tricle of mouse brain), or blood flow (heart development in zebrafish). During C. elegans development,embryos elongate 4-fold without additional cell division or migration. This process is highly robust andinvariable. Previous studies demonstrated that hemidesmosomes (cell attachments to the extracellularmatrix) play a critical role in mechanosensing by stabilizing the sca↵olding protein GIT-1 in responseto muscle input, but little is known about how it works at the molecular level (Zhang et al., 2011).Therefore we aimed to characterize a putative binding partner of the earliest known e↵ector (GIT-1)of mechanosensing. For this, we used both in vitro and in vivo (CRISPR-CAS9 ) tools to identifyits binding partners (if any). Interestingly, we found that a core component of the hemidesmosomei.e., VAB-10 strongly interacts with GIT-1 molecularly and genetically. Far-Western blotting suggeststhat purified VAB-10 and GIT-1 interact molecularly in vitro. Genetic interaction studies revealedthat a mutation a↵ecting the SH3 domain present within a spectrin repeat of VAB-10 strongly in-teracts with mutations in git-1 and also with pak-1 (a player of mechanotransduction pathway). Indouble mutants background, embryos arrested prior to the two-fold stage, a phenotype also noticed inhemidesmosome-deficient embryos. This result suggests that the SH3 domain of VAB-10 provides aninteraction platform for diverse players in response to physical cues in mechanosensing pathway. Wewould also like to extend our studies in the context of characterizing mechanosensing properties usinga combination of genetic tools (transgenic line) in vivo, and biophysical tools (AFM) in vitro. Thus,understanding how mechanosensors and their signaling cascades operate should elucidate a cellularphenomenon in a better way.

⇤Speaker

†Corresponding author: michel.labouesse@upmc.fr

31

P15 – Identification of novel regulators ofGABAergic synaptogenesis in the nematode

Caenorhabditis elegans.

Marine Gueydan ⇤ 1, Berangere Pinan-Lucarre 1, Aurore Valfort-Cecile 1,Jean-Louis Bessereau† 1

1 Centre de genetique et de physiologie moleculaire et cellulaire (CGphiMC) – CNRS : UMR5534, UniversiteClaude Bernard - Lyon I – UNIVERSITE CLAUDE BERNARD LYON 1 Batiment Gregor Mendel 16 rue

Raphael Dubois 69622 VILLEURBANNE CEDEX, France

In the central nervous system, the inhibitory system plays a key role in neuronal network excitabil-ity and defects in the excitatory vs inhibitory balance could lead to neuropathies.To identify novel genes and mechanisms involved in the formation and the regulation of inhibitorysynapses, we use the inhibitory GABAergic neuromuscular junction (NMJ) of the nematode Caenorhab-ditis elegans as a genetically tractable model. At these synapses, fast neurotransmission is ensured bytype A ionotropic GABA receptors (GABAR), which form post-synaptic clusters in front of GABArelease sites.Specifically, we performed an EMS genetic screen based on the direct visualization of fluorescentlytagged GABAR in vivo in a knock-in strain. We identified 35 mutants with abnormal GABAR local-ization among the 1728 mutagenized haploid genomes isolated. We characterized and categorized afirst set of 13 mutants that displayed strong GABAR mislocalization. We used a novel whole genomesequencing strategy to simultaneously map and identify mutations responsible for the GABAR local-ization defect without any prior time-consuming genetic mapping. We are currently validating someof the potential mutations and reproducing the procedure for a second set of mutants to enlarge ourcandidate genes list.

⇤Speaker

†Corresponding author: jean-louis.bessereau@univ-lyon1.fr

32

P16 – Micro-movements of the mitotic spindlepoles reveal cell division mechanics.

Benjamin Mercat 1, Xavier Pinson ⇤ 1, Helene Bouvrais 1, Jacques Pecreaux 1

1 Institute of Genetics and Developmental biology of Rennes (IGDR) – CNRS, Universite de Rennes 1 – CNRSUMR 6290 - Faculte de Medecine (Univ. Rennes 1) 2 avenue du Prof. L. Bernard, CS 34317, 35043 Rennes

cedex, France, France

Mitosis and the correct segregation of genetic material lie at the heart of development and survivalof all living organisms. The mitotic spindle, indispensable to these processes, is a structure comprisingdynamical microtubules as well as a variety of molecular motors and their regulators. Although thespindle has been extensively studied biochemically, its dynamics and that of its various componentsremain elusive. To study the dynamics of the mitotic spindle, we developed an image processing base,non-invasive method combined to a heuristic model to accurately measure mechanical parameters alongtime.We used this to address how forces (cortex-, kinetochore- and spindle midzone-generated) are regulatedwithin the mitotic spindle of the C. elegans one-cell embryo. Indeed, forces have been proposed to beessential for the detection and correction of merotelic chromosome attachments that escape the controlof the metaphase/anaphase checkpoint and can give rise to aneuploidy.

To this end, we tracked fluorescently labeled spindle pole at high temporal and spatial resolution andanalysed micro-fluctuations of spindle length in vivo, to obtain a blueprint of the mechanical behaviorof the spindle and its evolution over time. In control embryos, metaphase appeared dominated bydamping, consistent with the slow spindle elongation observed. At anaphase onset, mechanical ”rigid-ity” collapsed, before slowly increasing about 50s later to reach a regime where damping and inertiadominated, suggesting a dramatic re-arrangement of the spindle.Our investigations of the micro-movements enabled us to probe the mitosis mechanics close to thephysiological conditions with a minimally perturbative approach. This is being applied to characterizethe roles of forces in the post-anaphase correction mechanism of merotelic attachments and paves theway to understanding yet elusive and poorly studied properties of the mitotic spindle.

⇤Speaker

33

P17 – The C. elegans K cell as a new model tostudy cellular potential, asymmetric cell

division and cell type conversion

Christelle Gally ⇤ 1, Martina Hajduskova , Sophie Jarriault† 1

1 IGBMC – CNRS UMR 7104, Inserm U 964, UdS – 1 rue Laurent Fries / BP 10142 / 67404 Illkirch CEDEX,France

Asymmetric cell division (ACD) ensures the balance between cell proliferation and di↵erentiation.Stem cells undergo ACD to self-renew while giving rise to a daughter cell that enters the di↵erentiationpath. To date diverse mechanisms of ACD have been described in di↵erent experimental models.However, the complex regulation network of ACD and its impact on stem cell potential is still not fullyunderstood. The studies of stem cells ACD in vitro have several limitations, such as absence of thenatural cellular environment which may impact on self-renewal abilities, the symmetry of the divisionor the restriction of cellular potential.Here, we introduce a new cellular in vivo model to study ACD impact on cellular potential within acomplex tissue context, namely the rectal epithelial tissue, yet at a single-cell resolution. In C. elegans,an epithelial cell named ”K” is a part of the larval rectal tube. Interestingly, during development theK cell, which has all features of a fully di↵erentiated epithelial cell, divides in a stem cell-like mannerto produce the rectal epithelial cell K.a and another daughter cell (K.p) that then becomes the DVBneuron.In order to understand the mechanism(s) controlling the K-to-DVB formation, we have performed anRNAi screen and tested several genes known to be important in ACD. Furthermore, we have identifiedK, K.a and K.p-specific markers and investigated their temporal activity. Owing to these markers,we have been able to characterize how the K cell division is a↵ected in mutants that lack the DVBneuron. We have started to elucidate the relationships between key genetic players of the K celldivision. Currently, we are testing how the orientation of the K cell division impacts on K.p cell fateand what mechanisms might be at play after ACD to convert the K.p daughter into a DVB neuron.Our powerful cellular in vivo model allows dissecting the molecular circuitry governing the decisionbetween self-renewal and commitment to di↵erentiation.

⇤Speaker

†Corresponding author: sophie@igbmc.fr

34

P18 – DRP-1, AIF and mTOR : a link betweenmitochondria morphology and muscle

degeneration in C. elegans ?

Charlotte Scholtes ⇤ 1, Stephanie Bellemin 1, Edwige Martin 1, MaıteCarre-Pierrat 2, Marie-Christine Mariol 1, Kathrin Gieseler 1, Ludivine Walter

1

1 Centre de genetique et de physiologie moleculaire et cellulaire (CGphiMC) – CNRS : UMR5534, UniversiteClaude Bernard - Lyon I (UCBL) – UNIVERSITE CLAUDE BERNARD LYON 1 Batiment Gregor Mendel 16

rue Raphael Dubois 69622 VILLEURBANNE CEDEX, France2 Plateforme ”Biologie de Caenorhabditis elegans” – CNRS : UMS3421 – Universite Claude Bernard - Lyon I

batiment G. Mendel 16, rue Raphael Dubois 69622 Villeurbanne Cedex, France

Muscle degeneration is a common feature of muscle aging and muscular dystrophies such as DuchenneMuscular Dystrophy (DMD). Our lab has established a Caenorhabditis elegans mutant with progressivedystrophin-dependent muscle degeneration: the dys-1(cx18);hlh-1(cc561) double mutant worm calledthe C. elegans DMD model. This model exhibits dramatic changes in mitochondrial morphology com-pared to wild-type worms suggesting a deregulation in the fusion/fission mitochondrial balance. Mygoal is to shed light on the role of mitochondria dynamics in the molecular mechanisms leading tomuscle degeneration.To start, we first focused on DRP-1, a protein required for mitochondrial fission. We introduced in theC. elegans DMD model a null mutation drp-1(tm1108). The DMD;drp-1(tm1108) mutants presentedreduced mitochondrial fragmentation compared to DMD mutants. Furthermore, DMD;drp-1(tm1108)mutants exhibited reduced muscle degeneration and increased mobility. DRP-1 is well known to be im-plicated in cell death processes. In C. elegans, the pro-apoptotic function of DRP-1 is dependent on itscleavage by the CED-3 caspase. We generated DMD;drp-1(tm1108) transgenic lines expressing DRP-1with mutated CED-3 cleavage site. Interestingly, our data suggest that DRP-1 cleavage by CED-3is required for DRP-1 to decrease muscle degeneration. Altogether, the pro-fission and pro-apoptoticprotein DRP-1 seems to be implicated in pathological muscle degeneration.

After these first observations, we aimed at identifying other genetic suppressors of dystrophin de-pendent muscle degeneration playing a role in mitochondria dynamics. Large screen on the C. elegansDMD model allowed for the identification of 60 genes, which decrease muscle degeneration after RNAiknock-down. Among them, we identified 28 candidate genes that participate in mitochondria biology.We tested the 28 RNAi candidates for an e↵ect on mitochondria morphology of DMD worms. Wefound that knock-down by RNAi of wah-1 (AIF homolog) and let-363 (mTOR homolog) can reducemitochondrial fragmentation of DMD mutants. Our findings provide the first evidence that WAH-1a↵ects mitochondria morphology in muscle cells.Moreover, reducing WAH-1 or LET-363 levels in absence of DRP-1 can further decrease muscle degen-eration of the C. elegans DMD model than wah-1 RNAi or let-363 RNAi or drp-1(tm1108) mutationalone suggesting at least in part distinct molecular pathways.

⇤Speaker

35

P19 – Is unc-70/�-spectrin a functionalregulator of the neuronal potassium channel

unc-58?

Philippe Tardy ⇤ 1, Melissa Zouak 1, Thomas Boulin† 1

1 Institut NeuroMyoGene (INMG) – Universite Claude Bernard-Lyon I - UCBL (FRANCE) – 8 RUERAPHAEL DUBOIS, 69100 VILLEURBANNE, France

Two-pore domain potassium channels (K2P) compose a family of highly conserved potassium-selective ion channels responsible for the establishment and maintenance of the electrical membranepotential of metazoan cells. Despite their fundamental role, little is known about the cellular processesthat control K2P channel function in vivo. In particular, we know only few factors that directly controlthe number, the activity and the localization of K2Ps at the cell surface. Thus, we have performeda large-scale genetic screen targeting the neuronal UNC-58 channel in order to identify new specificregulators of neuronal K2P channels in C. elegans.Gain-of-functions mutants of unc-58 display a strong paralysis phenotype (e665, Brenner, 1974). UsingMos1 and EMS mutagenesis, we have isolated 97 intragenic and 36 extragenic suppressor mutants. Wehave found that complete loss of UNC-58 function is associated with a significant decrease in thrashingfrequency, comparable to the loss of the main cholinergic receptor at neuromuscular junctions. Thissuggests an important role for UNC-58 in the neuromuscular system.

Among our extragenic suppressors, we have found three alleles of unc-70/�-spectrin and three alleles ofunc-44/ankyrin. These cytoskeletal proteins interact with each other to form a membrane endoskeletonensuring elasticity of neuronal and erythrocyte plasma membranes. In C. elegans, mutants of unc-70possess a striking phenotype in which the axons of GABAergic motoneurons are very fragile and breakduring post-embryonic development due to mechanical stress (Hammarlund, 2007). Our three mutantsare likely hypomorphic alleles, since they are much healthier than unc-70 null mutants. They stilldisplay axon breakage defects, albeit at a lower penetrance than null mutants. Moreover, the pene-trance for axon breakage is variable between each of the three alleles, even if they equally suppressunc-58(e665). Surprisingly, while axon breakage is reported to occur in GABAergic and cholinergicneurons alike, a large number of unidentified motoneurons expressing UNC-58 show no axon breakagedefects in our unc-70 mutants. Our results suggest that these new alleles may allow us to geneticallydissociate �-spectrin role between maintenance of axonal integrity and regulation of UNC-58 function.We can formulate two main hypotheses concerning the suppression of unc-58(e665) by the loss ofunc-70. (1) The channel could be regulated by a direct interaction with the spectrin network. Such in-teraction has already been reported in mammalian cardiomyocyte for the TREK-1 K2P channel (Hund,2014), although the nature of this interaction has not been yet elucidated. We are currently generatingknockin strains for UNC-58 to visualize channel expression and localization in vivo. Alternatively, (2)loss of �-spectrin could indirectly suppress unc-58(e665) behavior by disrupting the neuronal network.We have begun observing the architecture of di↵erent neuron classes to address this hypothesis.

⇤Speaker

†Corresponding author: thomas.boulin@univ-lyon1.fr

36

P20 – The role of sel-10 in transdi↵erentiation

Cecile Delance ⇤† 1, Steven Zuryn 2, Sophie Jarriault 1

1 Labo Jarriault – IGBMC – 1, rue Laurent Fries, France2 labo Zuryn – Queensland Brain Institute The University of Queensland Brisbane, 4072 Queensland, Australia

Transdi↵erentiation (TD) is a process during which one di↵erentiated cell changes its identity andbecome another specialized cell type. In our laboratory, we study a well-characterized single celltransdi↵erentiation event which occurs naturally in the rectum of the worm. One of the 6 rectal cells,named Y, transdi↵erentiates into the PDA motor neuron (Y-to-PDA). This mechanism begins in Y atthe L1 larval stage and is completed at the L3 larval stage. In this poster, I present our study on sel-10which is an ubiquitin ligase E3 involved in Y-to-PDA transdi↵erentiation. We found that sel-10 isgenetically interacting with an histone demethylase (JMJD-3.1) which also have a positive role duringTD. One model is that SEL-10 ubiquitinates a substrate which acts as a probable repressor of Y-to-PDATD, triggering its degradation by the proteasome. To test this hypothesis, we are examining whichSCF complex is involved in Y transdi↵erentiation. In addition, we have set up di↵erent strategies, usinggenetics and RNAi screening approaches, to identify SEL-10 substrate(s). We will thus report on ourprogresses at the meeting.

⇤Speaker

†Corresponding author: delance@igbmc.fr

37

P21 – Cryptic evolution behind a conservedasymmetric embryonic division in nematodes

Marie Delattre ⇤ 1, Aurore-Cecile Valfort , Caroline Launay 2, Marie Semon

1 Laboratoire de Biologie Moleculaire de la Cellule (LBMC) – CNRS : UMR5239, Universite Claude Bernard -Lyon I, Ecole Normale Superieure (ENS) - Lyon – ENS de Lyon 46 allee d’Italie 69364 LYON Cedex 07, France

2 Laboratoire de biologie moleculaire de la cellule (LBMC) – UMR5239, Ecole Normale Superieure de Lyon,Universite Claude Bernard Lyon, Hospices Civils de Lyon – Laboratoire de Biologie Moleculaire de la Cellule

UMR5239 CNRS/ENS Lyon/UCBL/HCL Ecole normale superieure de Lyon 46, allee d’Italie 69364 Lyon cedex07, France

Very little attention has been given to the pattern of variations for cellular traits across evolution.This contrasts with numerous studies on the evolutionary dynamics of molecules, genomes and devel-opmental processes. Because evolutionary changes ultimately arise from changes at the cellular level,the evolutionary dynamics of cellular processes remains to be explored. We are studying the evolutionof the mitotic spindle, by using nematode embryos as a cellular model.Mitotic spindle dynamics has been extensively studied the one-cell embryo of C. elegans. As the spindleelongates during anaphase, it becomes asymmetrically positioned, giving rise to two daughter cells ofunequal size and fate. We quantified spindle movements in ˜40 di↵erent species of nematodes for whichthe first embryonic division is also asymmetric. We discovered that this conserved output phenotypeis achieved by a very di↵erent combination of spindle movements between species. This demonstratesthat cryptic changes in the mechanical forces and/or material properties of the spindle have occurredacross nematode evolution.We have analysed the pattern of variation with the explicit aim of i) uncovering the directionality ofchanges across the phylogeny and ii) uncovering the conserved properties of the mitotic spindle.

⇤Speaker

38

List of participants

• majdouline.abou-ghali@curie.fr :: Abou-Ghali Majdouline

• hugo.aguilaniu@ens-lyon.fr :: Aguilaniu Hugo

• sara.alrawi@yahoo.fr :: Al Rawi Sara

• alkan@biologie.ens.fr :: Alkan Cigdem

• olga.andrini@univ-lyon1.fr :: Andrini Olga

• mathieu.baritaud@univ-lyon1.fr :: Baritaud Mathieu

• beckers@igbmc.fr :: Becker Sarah

• cecile.bedet@ens-lyon.fr :: Bedet Cecile

• stephanie.bellemin@hotmail.fr :: Bellemin Stephanie

• belougne@ciml.univ-mrs.fr :: Belougne Jerome

• vincent.bertrand@univ-amu.fr :: Bertrand Vincent

• jean-louis.bessereau@univ-lyon1.fr :: Bessereau Jean-Louis

• guillaume.bordet@univ-amu.fr :: Bordet Guillaume

• thomas.boulin@univ-lyon1.fr :: Boulin Thomas

• helene.boyer@ens-lyon.fr :: Boyer Helene

• bulle@ciml.univ-mrs.fr :: Bulle Maxime

• caillard@ciml.univ-mrs.fr :: Caillard Celine

• matthieu.caron@ens-lyon.fr :: Caron Matthieu

• maite.carre-pierrat@univ-lyon1.fr :: Carre-Pierrat Maıte

• manuela.dalessandro2@gmail.com :: Dalessandro Manuela

• delance@igbmc.fr :: Delance Cecile

• jane-lynda.deuve@upmc.fr :: Deuve Jane

• elmouridi.sonia@gmail.com :: El Mouridi Sonia

• ewbank@ciml.univ-mrs.fr :: Ewbank Jonathan

• felix@biologie.ens.fr :: Felix Marie-Anne

39

• nadine@igbmc.fr :: Fischer Nadine

• flore.beurton@ens-lyon.fr :: Flore Beurton

• gally@igbmc.fr :: Gally Christelle

• steve.garvis@ens-lyon.fr :: Garvis Steven

• mg3088@columbia.edu :: Gendrel Marie

• kathrin.gieseler@univ-lyon1.fr :: Gieseler Kathrin

• jose-eduardo.gomes@u-bordeaux.fr :: Gomes Jose-Eduardo

• laure.granger@univ-lyon1.fr :: Granger Laure

• manon.grosmaire@ens-lyon.fr :: Grosmaire Manon

• manish.grover@ens-lyon.fr :: Grover Manish

• dguet@hamamatsu.fr :: Guet David

• marine.gueydan@univ-lyon1.fr :: Gueydan Marine

• lehe@ciml.univ-mrs.fr :: He Le

• marion.herbette@ens-lyon.fr :: Herbette Marion

• ho↵yoes@igbmc.fr :: Ho↵ Sarah

• nicolas.joly@ijm.fr :: Joly Nicolas

• jospin@univ-lyon1.fr :: Jospin Maelle

• iskra.katic@fmi.ch :: Katic Iskra

• shilpa.ncbs@gmail.com :: Kaur Shilpa

• viviane.laine@univ-lyon1.fr :: Laine Viviane

• alicia.lardennois@upmc.fr :: Lardennois Alicia

• caroline.launay@ens-lyon.fr :: Launay Caroline

• anne.laurenconloviton@ens-lyon.fr :: Laurencon Anne

• legalt@igbmc.fr :: Le Gal Thomas

• slee@ciml.univ-mrs.fr :: Lee Song Hua

• slee@ciml.mrs-univ.fr :: Lee Song Hua

• lone@ciml.univ-mrs.fr :: Lone Jean-Christophe

• camilla.luccardini@univ-lyon1.fr :: Luccardini Camilla

• mangolds@igbmc.fr :: Mangold Severine

• marie-christine.mariol@univ-lyon1.fr :: Mariol Marie-Christine

• edwige.martin@univ-lyon1.fr :: Martin Edwige

• lisa.martino@ijm.fr :: Martino Lisa

40

• cecile.menez@toulouse.inra.fr :: Menez Cecile

• marine.mercier@univ-lyon1.fr :: Mercier Marine

• adeline.mergoud@gmail.com :: Mergoud Dit Lamarche Adeline

• jorge.merlet@upmc.fr :: Merlet Jorge

• gmichaux@univ-rennes1.fr :: Michaux Gregoire

• s.moal@gatc-biotech.com :: Moal Stephane

• laurent.molin@univ-lyon1.fr :: Molin Laurent

• nicole.mounier@univ-lyon1.fr :: Mounier Nicole

• nicole.mounier@univ-lyon1.fr :: Mounier Nicole

• wallis.nahaboo@ens-lyon.fr :: Nahaboo Wallis

• christian.neri@inserm.fr :: Neri Christian

• francesca.palladino@ens-lyon.fr :: Palladino Francesca

• charlene.perrois@upmc.fr :: Perrois Charlene

• berangere.pinan-lucarre@univ-lyon1.fr :: Pinan-Lucarre Berangere

• xavier.pinson@univ-rennes1.fr :: Pinson Xavier

• lionel.pintard@ijm.fr :: Pintard Lionel

• julie.plastino@curie.fr :: Plastino Julie

• pujol@ciml.univ-mrs.fr :: Pujol Nathalie

• richaud@biologie.ens.fr :: Richaud Aurelien

• benedicte.richaudeau@univ-lyon1.fr :: Richaudeau Benedicte

• valerie.robert@ens-lyon.fr :: Robert Valerie

• oceane.romatif@univ-lyon1.fr :: Romatif Oceane

• charlotte.scholtes@etu.univ-lyon1.fr :: Scholtes Charlotte

• florence.solari@univ-lyon1.fr :: Solari Florence

• shashi.suman@upmc.fr :: Suman Shashi Kumar

• ta↵oni@ciml.univ-mrs.fr :: Ta↵oni Clara

• 100rabh.tak@gmail.com :: Tak Saurabh

• philippe.tardy.fr@gmail.com :: Tardy Philippe

• thakur@ciml.univ-mrs.fr :: Thakur Nishant

• ilhemtb@hotmail.fr :: Touba Ilhem

• aurore-cecile.valfort@univ-lyon1.fr :: Valfort Aurore-Cecile

• thanh.vuong@upmc.fr :: Vuong Thanh

41

• ludivine.walter@univ-lyon1.fr :: Walter Ludivine

• ludivine.walter@univ-lyon1.fr :: Walter Ludivine

• alexis.weinreb@univ-lyon1.fr :: Weinreb Alexis

• gaotian52@hotmail.com :: Zhang Gaotian

42

Author Index

AHIER, Arnaud, 29Al Rawi, Sara, 16Atlas, Emily, 5

Barbry, Pascal, 10BARITAUD, Mathieu, 13Bedet, Cecile, 9BELLEMIN, Stephanie, 35BELOUGNE, Jerome, 19Bertrand, Vincent, 25, 26BESNARD, Fabrice, 14Bessereau, Jean-Louis, 32bessereau, Jean-Louis, 6Beurton, Flore, 9Boned, Annie, 18, 21Bordet, Guillaume, 26Boulin, Thomas, 7, 36Bouvrais, Helene, 33BULLE, Maxime, 21

Caillard, Celine, 19Caron, Matthieu, 9, 30Carre-Pierrat, Maıte, 35Couillault, Carole, 26

Daignan-Fornier, Bertrand, 20DELANCE, Cecile, 37Delattre, Marie, 28, 38Deuve, Jane, 16

el mouridi, sonia, 7Ewbank, Jonathan, 10, 11, 18, 21, 27

Felix, Marie-Anne, 24, 28FELIX, Marie-Anne, 14

Gally, Christelle, 34Galy, Vincent, 16Garvis, Steve, 30Gendrel, Marie, 5GIESELER, Kathrin, 13, 35Gieseler, Kathrin, 6Gomes, Jose-Eduardo, 20Grosmaire, Manon, 28Grosshans, Helge, 22Gueydan, Marine, 32

Hajduskova, Martina, 34HE, LE, 10Hendriks, Gert-Jan, 22Herbette, Marion, 30Hobert, Oliver, 5

Jarriault, Sophie, 29, 34, 37

Kansoh, Dalia, 23Katic, Iskra, 22Kaur, Shilpa, 25

LABOUESSE, Michel, 31Labouesse, Michel, 12Lanteri, Lilian, 26Launay, Caroline, 28, 38Le Gal, Thomas, 29Lebrigand, Kevin, 10Lecroisey, Claire, 7Lee, Song Hua, 18Lenne, Pierre, 25Lespine, Anne, 23Lone, Jean-Christophe, 27

Melenec, Pauline, 26Marguet, Didier, 11MARIOL, Marie-Christine, 13, 35Marsac, Roxane, 20MARTIN, Edwige, 13, 35martino, lisa, 15Menez, Cecile, 23Mercat, Benjamin, 33MERCIER, Marine, 30Mergoud dit Lamarche, adeline, 6Merlet, Jorge, 16Molin, Laurent, 6

Omi, Shizue, 18, 21

Pecreaux, Jacques, 33Palandri, Amandine, 26Palladino, Francesca, 9, 30Perrois, Charlene, 16Pinan-Lucarre, Berangere, 32Pinson, Xavier, 33Pintard, Lionel, 15Pujol, Nathalie, 10, 11, 18, 21, 27

Robert, Valerie, 30

Semon, Marie, 38Saint-Marc, Christelle, 20SCHOLTES, Charlotte, 35Solari, Florence, 6

43

SUMAN, Shashi Kumar, 31Sutra, Jean-Francois, 23

Ta↵oni, Clara, 11Tardy, Philippe, 7, 36Thakur, Nishant, 21

Valfort, Aurore-Cecile, 38Valfort-Cecile, Aurore, 32Vuong-Brender, Thanh, 12

WALTER, Ludivine, 35

Xu, Lan, 22

ZHANG, Gaotian, 24Zouak, Melissa, 7, 36Zuryn, Steven, 37

44