Transgenic animals :

Transgenic animals BY SURAJ PARSI M PHARM 2ND SEM

Definition: :

Definition: A Transgenic animal is one that carries a foreign gene that has been deliberately inserted intoits genome. The foreign gene is constructed using recombinant DNA methodology

advantages : :advantages : Increased growth rate Improved disease resistance Improved food conversion rates Leaner 

meat Increased muscle mass Improved nutritional quality Improved wool quality

disadvantages :

disadvantages Inserted gene has more than one function. Breeding problems Expensive Sometimes leads

to mutagenesis and functional disorders. Low survival rate of transgenic animals

Slide 5:Some of the goals of transgenic animal creation are: Research into animal and human disease Improvelivestock animals Use of animals as bioreactors

METHODS INVOLVE TO PRODUCE OR TO MAKE TR ANSGENIC ANIMALS :

METHODS INVOLVE TO PRODUCE OR TO MAKE TRANSGENIC ANIMALS The EmbryonicStem Cell Method The Pronucleus Method Retro virus mediated gene transfer.

The Embryonic StemCell Method (Method "1") :

The Embryonic Stem Cell Method (Method "1") Make your DNA Using recombinant DNA methods, build molecules of DNA containing the structural gene you desire (e.g., the insulin gene) vector DNA toenable the molecules to be inserted into host DNA molecules Promoter and enhancer sequences to enable

the gene to be expressed by host cells Transform ES cells in culture Expose the cultured cells to the DNAso that some will incorporate it.

Slide 8:Select for successfully transformed cells. Inject these cells into the inner cell mass (ICM) of mouse

 blastocysts. Embryo transfer Prepare a pseudopregnant mouse (by mating a female mouse with a

vasectomized male). The stimulus of mating elicits the hormonal changes needed to make her uterusreceptive. Transfer the embryos into her uterus. Hope that they implant successfully and develop into

healthy pups

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6. Test her offspring Remove a small piece of tissue from the tail and examine its DNA for the desired

gene. No more than 10±20% will have it, and they will be heterozygous for the gene. 7. Establish atransgenic strain Mate two heterozygous mice and screen their offspring for the 1:4 that will behomozygous for the transgene. Mating these will found the transgenic strain.

The Pronucleus Method (Method "2") :

The Pronucleus Method (Method "2") 1. Prepare your DNA as in Method 1 2.Transform fertilized eggsHarvest freshly fertilized eggs before the sperm head has become a pronucleus. Inject the male pronucleuswith your DNA. When the pronuclei have fused to form the diploid zygote nucleus, allow the zygote to

divide by mitosis to form a 2-cell embryo. 3. Implant the embryos in a pseudopregnant foster mother and

 proceed as in Method 1.

 

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An Example This image shows a transgenic mouse (right) with a normal littermate (left). The giant mousedeveloped from a fertilized egg transformed with a recombinant DNA molecule containing: the structural

gene for human growth hormone a strong mouse gene promoter The levels of growth hormone in theserum of some of the transgenic mice were several hundred times higher than in control mice.

METHODS-3: R ETRO VIR US MEDIATED GENE TR ANSFER :

METHODS-3: RETRO VIRUS MEDIATED GENE TRANSFER Retroviruses used as vectors to transfer genetic material into the host cell, resulting in a chimera, an organism consisting of tissues or parts of diverse genetic constitution Chimeras are inbred for as many as 20 generations until homozygous

(carrying the desired transgene in every cell) transgenic offspring are born The method was successfully

used in 1974 when a simian virus was inserted into mice embryos, resulting in mice carrying this DNA

DIFFER ENT ANIMALS WHICH CAN BE GENETICALLY MODIFIED: :DIFFERENT ANIMALS WHICH CAN BE GENETICALLY MODIFIED: Mice Sheep Goat Chicken

Pigs Fish Guinea pigs Rabbits Cows Rats Cats Dog Horse

Examples of Transgenic Animals :

Examples of Transgenic Animals

TransgenicCattle :

Transgenic Cattle Dairy cows carrying extra copies of two types of casein genes produce 13% more milk  protein Not only will this make the milk more nutritious, it would allow for less milk to make morecheese Currently the milk from these animals is under FDA review

EnviroPig :EnviroPig Transgenic pigs express phytase in their salivary glands Phytic acid in the pig meal is degradedreleasing phosphorus The phosphorus is absorbed by the pig Normally the phytic acid/phosphorus

complex passes through the pig and is excreted as waste Pig waste is a major pollutant & can causeeutrophication of lakes & streams

Slide 18:USES: Organ transplant harvesting Study of human membrane co-factor protein DISADVANTAGES: 1.

Breeding problem 2. Mutation will occur 

Transgenic Fish :

Transgenic Fish Tilapia Salmon/trout Catfish Can grow up to 6 times faster than wildtype fish Most have

extra copies of growth hormone (GH) gene

TR ANSGENIC SHEEP :TRANSGENIC SHEEP 1997, Tracy the sheep, the first transgenic animal to produce a recombinant

 protein drug in her milk alpha-1-antitrypsin (AAT) treatment for emphysema & cystic fibrosis Created by

PPL Therapeutics & The Roslin Institute

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USES OF TRANSGENIC AND GENETICALLY MODIFIED SHEEP: Its used as model for studying of:1.Immunology 2.Human blood clotting factor8 3.Transplantation 4.Haematology 5.Biological product

manufacturing 6.Recombinant DNA 7. Drug production in milk 

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DISADVANTAGES: Difficult procedure Failed in vitro fertilization expensive

TR ANSGENIC MICE :

TRANSGENIC MICE

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Knock-out technology allows for the specific loss of a gene in mice p27 knockout mouse is bigger thanthe control This is not due to obesity, but the skeletal structure is increased in size

Slide 25:USES OF TRANSGENIC MICE: Which is used in studying of: 1.gene mutation 2.Alzhimer¶s disease

3.Hypertension 4.Atherosclerosis 5.cardiac hypertrophy 6.human leukocyte antigen 7.human gastriccarcinoma 8.making poliovirus vaccine 9. different type of cancer 10.HIV 11.ocular inflammation 12.

hepatitis B virus 13.spinal muscular atrophy (knock-out) DISADVANTAGES OF TRANSGENIC MICE:Expensive Gene can only be added not deleted Embryos are not easily accessible for manipulation

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TRANSGENIC MONKEY: Its so similar to human hence it used in clinical trail used for studing : 1.HIV

2. Huntington¶s disease DISADVANTAGES : Expensive Difficult Breeding problems

TR ANSGENIC R ABBIT :

TRANSGENIC RABBIT Alba, the EGFP (enhanced GFP) bunny Created in 2000 as a transgenic artwork 

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USES OF TRANSGENIC RABBITS: Transgenic rabbits are used in studing of: 1.Hemorrhagic disease2.Gene mutation 3.Cell metabolisms 4.Eye disease 5.Heart problems 6.Atherosclerosis 7.Retinaldegeneration DISADVANTAGES OF TRANSGENIC RABBIT: 1-Has low metabolic rate per unit area

2-Drink very less during dehydration 3-Has ability to taste water which is absent in human and mice. 4-Cant vomit

References :References WWW .BIOSCIENCE. ORG PRIMROSE & TWYMAN Principles of gene manipulations

PEPIN, M.C., POTHIER, F.AND BURDEN nature 355, 725-728 SHARMA et. al toxicologic pathology

vol 35 No 7, 984-999(2007) TRANSGENIC ANIMALS Annual review of pharmacology vol 36 USERS.RCN.COM /JKIMBALL .MA ULTRANET/BIOLOGYPAGES