knockout animals or knockout mice

1. KNOCKOUT
ANIMALS
DEPARTMENT OF ZOOLOGY
Dr. Harisingh Gour University
sagar

2. Presented by Lekhan Lodhi

3. THE KNOCKOUT MICE

5. WHAT ARE KNOCKOUT MICE??
 A mouse in which gene is deactivated or mutated
 Specific gene is targeted
 The loss of gene activity often causes change in
mouse’s phenotype and thus provides valuable
information on the function of the gene

6. THE NOBLE PRIZE WINNERS
The noble prize in physiology or medicine in 2007
was awarded jointly to -
Mario R. Capecchi, (gene knockout)
Sir Martin J. Evans, (cultivation of ES Cells)
Oliver Smithies (gene targeting)
“for their discovery of principle for introducing
specific gene modifications in mice by the use of
embryonic stem cells.

7. TRANSGENIC v/s KNOCKOUT ANIMALS
 Transgenic
- gene (s) added can be
- A foreign gene
- Extra copies of endogenous gene
- Mutated endogenous gene
• Knockout animals
- Gene inactivated
- Homologous recombination

8. PURPOSES OF KNOCKOUT MICE
To know the valuable information about particular
gene
Human shares many genes with mice
How a similar gene may cause disease in human
To study different kinds of Cancers, Obesity, Heart
diseases, diabetes, Parkinson’s disease, Anxiety etc.
Inactivation of p53 gene (responsible for tumor
suppress) causes high risk of developing bone
cancer, breast cancer, blood cancer etc.

9. DRAWBACKS OF KNOCKOUT MICE
About 15% of knockout mice are lethal
Sometimes gene perform different function
in adult than in developing embryo
Sometimes a knockout gene may produce
different characteristics from those observed
in humans
For ex. Mutation in p53 gene causes tumors
in particular set of tissues but in mice
tumors develops in different tissues

10. HOW KNOCKOUT ANIMALS ARE MADE
 After four hours of fertilization brings out
Embryonic Stem(ES) cells
 Two methods are used to develop knockout
mice
1. Gene targeting
2. Gene trapping

11. GENE TARGETING
 It is also known as Homologous Recombination
 Manipulate the gene in the nucleus of ES cell.
 Introduce the artificial piece of DNA is homologous
to the gene.
 Cells machinery recognize that artificial piece of
DNA and swaps out the existing gene by that
artificial gene.
 The artificial DNA is inactive and bearing genetic tag
and use in tracking.
 It swaps or “knockout” the function of existing gene.

12. GENE TRAPPING
 Manipulate gene in ES cell
 Artificial piece of DNA containing genetic tag is
inserted randomly.
 Artificial DNA prevents RNA splicing machinery and
prevents existing gene from producing designated
protein.
 It causes knocking out the function of the existing
gene.

13. WHY ES CELLS ARE USED
ES cell grows in lab can be
used to make knockout mice
as long as 10 years after they
were harvested.