Knockout animals by lekhan

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

4. 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

5. 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.

6. 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

7. 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.

8. 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

9. 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

10. 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.

11. 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.

12. 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.

13. THANK YOU