Transgenic technology

1. Presented by:
Rishabh Maheshwari
M.Pharma
(MPC) Ist year,
SGSITS,Indore.

2.  Transgenic techniques describes the process of introducing foreign
deoxyribonucleic acid (DNA) into a host organism's Genome
 Transgenic techniques is a technique in which an organism (typically
a mouse) that is engineered to carry a foreign gene, or transgene of
choice as part of its own genetic material for Disease models and
human welfare.
 Transgenics are genetically modified organisms with DNA from
another source inserted into their genome. A large number of
transgenic animals have been created such as Mice, Cows, Pigs,
Sheep, Goats, Fish, and Frogs.
TRANSGENIC TECHNOLOGY

3.  DNA microinjection.
 Retrovirus-mediated gene transfer (RMGT).
 Sperm-mediated gene transfer (SMGT).
 Embryonic stem cell-mediated gene transfer.
METHODS USED FOR ANIMAL

4. In the past 20 years, DNA microinjection has become the most widely
applied method for gene transfer in animals.
Introducing the transgene DNA directly into the zygote at an
early stage of development. (No vector required)
This method involves:
1)Transfer of a desired gene construct (of a single gene or a combination of
genes that are recombined and then cloned) from another member of the same
species or from a different species into the pronucleus of a reproductive cell;
2)In vitro culture of the manipulated cells to develop to a specific embryonic
phase; and
3) Then transfer of the embryonic cells to the recipient female.
1. DNA Microinjection

5. Microinjection
into the germ line >
transgenic animal
Gene injected into the
male pronuclei (i.e
Pronuclei injn
)

6. 2. Retrovirus-mediated gene transfer
(RMGT) The word “retro” means, when the virus vectors infect a host cell, the
viral RNA is reverse transcribed in the cytoplasm making linear double-
stranded DNA.
 A retrovirus is a virus that carries its genetic material in the form of RNA
rather than DNA.
 In this method, retroviruses are 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.
 When cells are infected by retroviruses, the resultant viral DNA, after
reverse transcription and integration, becomes a part of the host cell
genome to be maintained for the life of the host cell.

7. 3. Sperm-mediated gene transfer (SMGT)
SMGT is a simple and efficient technique to produce transgenic mice.
Use of “Linker protein" to attach DNA to sperm which transfer the new
DNA during fertilization.

8.  The blastocyst (inner layer of a fertilized egg) is harvested and mixed
with recombinant DNA and inserted back in the blastocyst.
This method involves:
 Isolation of totipotent stem cells (stem cells that can develop into
any type of specialized cell) from embryos.
 The desired gene is inserted into these cells.
 Cells containing the desired DNA are incorporated into the host's
embryo.
4. Embryonic stem cell-mediated gene transfer

9.  In this technique, DNA was mixed with sperm cells before in vitro. 30% of
offspring mouse were integrated in foreign DNA.
 The basic principle of sperm-mediated gene transfer is: seminal plasma-free
sperm cells are suspended in the appropriate medium, and then incubated
with DNA.
 The resultant DNA-carrying sperms are then used to fertilize eggs, via in
vitro fertilization or artificial insemination or, in the case of aquatic animals,
via waterborne (natural) fertilization.

11.  Transgenic technology holds a great potential in different groups on the
basis of benefits of these animals to human welfare can be grouped
into areas:
1. Clinical Application,
2. Agricultural application,
3. Industrial application, and
4. Transgenic model (Mice).
APPLICATION OF TRANSGENIC
TECHNOLOGY

12. (A) Models for human disease
The biomedical sciences rely heavily on animal models as tools for the
discovery and development of therapeutic interventions. Some examples
include:
Gene Therapy: Human gene therapy involves adding a normal copy of a
gene (transgene) to the genome of a person carrying defective copies of the
gene.
Genetic basis of human and animal disease.
Disease resistance in humans and animals.
Drug and product testing and/or screening.
1. CLINICAL APPLICATION

13. (B) Production of Pharmaceutical in transgenic animals
The impact of transgenic animals on pharmaceutical development could
soon expand as recombinant proteins expressed and secreted by transgenic
animals move toward regulatory approval and production.
ATryn®, was the first product derived from a transgenic animal to be
submitted for formal regulatory approval in Europe or the USA.
(C) Transgenic expression of immunoglobulin's
Transgenic animal producing a disease specific Ig, chimeric Igs were
created by ligating the variable region exon of a previously characterized Ig
to the constant region exon.

14. (D)Xenotransplantation
 Transplanted organs may be obtained from transgenic animals. E.g.
Transgenic pigs may provide the transplanted organs needed to alleviate the
shortfall.
 Currently, xenotransplantation is hampered by a pig protein that can cause
donor rejection but research is underway to remove the pig protein and
replace it with a human protein. For organ and tissue transplantation, which
is known as a "species of daughter cells “

15. (A) Breeding
Traditional cross breeding have been used for ages to create chickens,
cows, pigs etc.
Farmers have always used selective breeding to produce animals that
exhibit desired traits (e.g., increased milk production, high growth rate).
Traditional breeding is a time-consuming, difficult task.
2. AGRICULTURAL APPLICATION

16. (B) Quality
 Herman, a transgenic bull carries a human gene for Lactoferrin
(gene responsible for higher iron content)
 Pigs and cattle that have more meat on them.
 Sheep that grow more wool.
 Eggs can be made healthier with high quality protein.

17.  By extracting polymer strands from the milk and weaving them
into thread, the scientists can create a light, tough, flexible material
that could be used in such applications as military uniforms,
medical micro sutures, and tennis racket strings.
 Microorganisms have been engineered to produce a wide variety of
proteins, which in turn can produce enzymes that can speed up
industrial chemical reactions.
3. INDUSTRIAL APPLICATION

18.  Genetically modified mice are the most common animal
model for transgenic research. Transgenic mice are
currently being utilized to study a variety of diseases
including cancer, obesity, heart disease, arthritis, anxiety,
and Parkinson’s disease.
 The two most common types of genetically modified
mice are knockout mice and oncomice .
4. TRANSGENIC MODEL (MICE)

19.  Transgenic mice can be used both as model systems for human diseases
and as test cases to determine if the production of a potential therapeutic
agent is feasible.
 However, a mouse or rodent is not a human being, even though it is a
mammal, and thus the information gathered from transgenic rodent is not
always medical relevant.
 But, on the other hand, clinical insight about the etiology of a complex
diseases can be discovered.
 This technique is used for the treament of Alzheimer disease, arthritis,
muscular dystrophy, tumorigenesis, hypertension, neurodegenerative
disorders, endocrinological dysfunction, coronary disease, obesity and
many others diseases.
USES OF ANIMAL MODEL

20. ADVANTAGES OF TRANSGENIC MODEL
These animals are very useful for delineating the function of newly
discovered genes as well as for producing useful proteins in large animals.
Transgenic animals are useful as disease models and producers of
substances for human welfare.
Regulation of gene expression.
Transgenic animals have potentially broad application for the
improvement of animal production quality, the enhancement of
productivity, the studies of human disease models and the production of
pharmaceuticals.

21.  Though the field of transgenic animals has advanced
considerably but few advancements are considered to be
most important.
• Introduction of the transgene
• Transgene integration
• Transgene expression
• Transgene transmission
• Use of embryonic stem cells
• Pharmaceutical products from transgenic animals
SOME IMPORTANT ADVANCES

22.  Many animals die or are born horribly disfigured as research is
conducted.
 Transgenic animals can radically change the direction of evolution,
which can result in drastic consequences for nature and humans
alike.
 Dietary and food safety concerns: Foreign gene inserted in the
chromosome locus may also result in different genetic changes in
different degrees, causing unintended effects.
 Environmental impacts: It may also lead to the loss of the wild life,
resulting in a decline in genetic diversity.
DISADVANTAGES OF TRANSGENIC
MODEL

23.  Transgenic technology have been developed rapidly and provided
more and improved platforms for the preparation of transgenic
animals since their emergence.
 All of these developments will provide new ideas and bring forth
important changes in fields like medicine, health and livestock
improvement.
 In particular, the economic and social benefits from the production
of bioreactors, drug production, and organ culture for human
transplantation will be great.
CONCLUSION

24. 1. Beardmore, J.A. (1997) Transgenics: autotransgenics and
allotransgenics. Transgen. Res.6,107–108.
2. Polites, H.G. and Pinkert, C.A. (2002) DNA Microinjection and
Transgenic Animal Production. In Transgenic Animal
Technology: A Laboratory Handbook(2nd edition) (Pinkert,
C.A.,ed.), pp. 15–70, Academic Press.
3. Dorling, A. and Lechler, R.I. (1997) Xenotransplantation:
immune barriers beyond hyperacute rejection . Clin. Sci.93,493–
505.
4. Brinster, R.L.et al.(1983) Expression of a microinjected
immunoglobulin gene in the spleen of transgenic
mice.Nature306, 332–336
REFERENCES

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