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1 . Which is the most unlikely involved in the intron-splicing of pre-mRNA ? [ a . U1 RNP; b . 5' cap structure; c . polyadenylation signal; d . secondary structure of pre-mRNA], give a brief explanation if you are not sure your answer (5%). - PowerPoint PPT Presentation
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1.Which is the most unlikely involved in the intron-splicing of pre-mRNA ? [a. U1 RNP; b. 5' cap structure; c. polyadenylation signal; d. secondary structure of pre-mRNA], give a brief explanation if you are not sure your answer (5%)
U1A protein inhibits polyadenylation of its pre-mRNA
U1A protein binds U1snRNA: 7-base sequence-U1A binding site
U1A protein inhibits polyadenylation of its pre-mRNA
U1A binding site2 copies in its own mRNA , at 3' end near the poly(A) signalprevent polyadenylation, but not the cleavage of pre-mRNArapidly degraded
U1A protein inhibits polyadenylation of its pre-mRNA
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prevent polyadenylation, but not the cleavage of pre-mRNAtruncated mRNA without poly(A) tail, rapidly degraded
apo-B (apolipoprotein B), serum protein of lipid transporter, CAA UAA, glutamine stop codon, in intestineboth liver and intestine forms transport lipidonly liver apo-B delivers cholesterol containing LDL
RNA editing in mammalian
Na+, Ca+2 ion channel, learning and memoryCAG CIG, glutamate arginine, Ca +2 cannot pass
Both editing of apo-B and glutamate receptor by RNA deaminases
RNA editing in glutamate receptor mRNA
Iron dependent regulation of TfR mRNA stability.
when iron ion high, IRE -BP inactive, cannot bind IRE,TfR mRNA is protected from degradation;when iron is low, IRE-BP is active and binds IRE. then TfR mRNA stability , TfR mRNA degraded
Iron dependent regulation of translation of ferritin stability.
ferritin is an intracellular protein that binds iron ionsferritin, 5' IRE free of BP, translation occurs, more ferritin.The IRE in ferritin mRNA has no AU rich
ferritin
Using Yeast to study Eukaryotic Gene Functionfrom Recombinant DNA (J Waston et al.) Ch 13
Size of genome in the selected organisms
Cloning yeast biosynthetic genes by complementation in E.coli
Yeast biosynthetic genes are cloned by complementation of E.coli mutations
Classes of yeast vectors
Shuttle vectors replicatein both E.coli and yeast
Cloning a yeast gene by complementation
Yeast genes can be cloned by simple complementation
Generation of temperature sensitive mutants of yeast
Replica plating
Gene targeting by homologous recombination
Homolgous recombination is a relative frequent event in yeast
Replacing a gene by transplacement
Tetrad analysis
Cloning genes required for matingreveals a signaling pathway similarto that seen in higher organisms
Pheromone signaling pathway
Cloning of the GPA1 gene as a high-copy suppressor of pheromone sensitivity
This fragment DNA only works in high copies, suggesting it was acting as a suppressor
The receptor swap experiment
Genetic experiments in yeast can answer precise biochemical questions
U2 RNA base-pairs with an intron sequence
Base pairing between U2 and branch point (in yeast)
A genetic assay for protein-protein interactions
Plasmid shuffle
Genetic analysisin yeast can be exploited to identify and studygenes from higher organisms