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8/4/2019 Transgenic Animals 1

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Transgenesisprocess of introducing foreign or exogenousDNA into an animals genome

TransgeneDNA introduced

MiceCows

FishBirdsSheepGoats


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Improve genetic Features of domesticated Animals

Provide animal models for study of human diseases

Pharming

using farm animals for production of human pharmaceuticals-mammary glands

Study the genes regulation, development of animals

How to Get the Transgene Inserted Retroviral Vectors

MicroinjectionEmbryonic stem cells


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FIGURE 22.13

A. Remove eggsB. Fertilize in vitro C. DNA is microinjected into male pronucleus (prior to nuclear fusion)

100-1000 copies of gene

D. Implant eggs into surrogate


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2003 John Wiley and Sons Publishers


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FIGURE 22.8 (19.1)

Infect early stage embryo with replication-defective retrovirus

Limitationsonly small DNA insertsno regulatory sequencessafety


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FIGURE 19.4

Remove pluripotent ES cells from blastocyst Transfect ES [Site specific Integration - advantage] Selection Microinject back into blastocyst Implant


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1. Determine whether the progeny are TRANSGENICpiece of tail, PCR, Southern Blot

2. Mate this transgenic animal to determine whether thetransgene is in GERM line

3. Breed to get homogenous transgenic line

Integration of DNAG0 generation -Mosiacs(G 1 progeny)

all cells contain transgene


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Quiescent [G0] cells Plus EGG

First 3 cell division of Fertilized Eggno gene expressionembryo-initiating protein factors in

cytoplasm bind to embryonicdevelopment genes

When G0 nucleus is transferredcell specific regulatory proteins are strippedEIPF bind to EDG


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YACs contained many of these heavy and light chain segments

Knock out Mouse Segments, replace wuth Human segment genes

Fully human antibody made


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Applications

Increasing casein content of milk increase cheese productionLactose free milk (transgene lactase)Resistance to bacterial infectionsIn vivo immunization

transgene is specific Heavy and Light chain genes whichcreate mAn against a specific antigen


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Easy to purify - few other proteins in milk Doesnt harm transgenic animal - no change to physiology

rProtein is authentically modified post-translationally

Large quantities

Renewable source

Mammary Gland-specific Promoters

promoter and transcription termination sequences are present


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PIGSPST porcine somatotropin (growth hormone)

adverse effects- kidney, stomach, heart, sterility

human Hemoglobinto replace whole blood transfusions

SHEEPIncrease wool production

keratin promotergrowth factor


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Pr

Problem: Rejection

Antibodies from Host bind to Donor Organ

Elicits Inflammatory ResponseTransplanted Organ Lost

Solution:Transgene in Donor for Complement-Inhibiting Protein


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Birdstraditional methods can not be used

because of avian embryogenesis differencesno ES cells found

ALV resistant chickenstransgene - defective ALV genome

makes viral RNA and protein

but blocks assembly of wt viral particlesFish

aquaculturetransgene - growth hormone

transgenic animals 1

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