Question

Yes or no, is this encoded by a proto-oncogene? (Please respond with Yes or No)

1. MAPKINASE (MAPK)

2. RB (inhibitor of cyclin dependent kinase)

3. BAX (promotes apoptosis)

4. BAD (an inhibitor of BCL2; BCL2 inhibits BAX)

5. P53

6. Cyclin

Answer 1

Normally cells have two types of genes responsible for cell growth ..PROTO- ONCOGENE and TUMOR SUPRESSOR GENE.

PROTO-ONCOGENES are genes which are involved in normal cell growth and proliferation.But they abliliy to become ONCOGENE (cancerous) when there is gain of function mutation occur in proto-oncogene. If a single gene is mutated they gain their function on the contrary TUMOR SUPRESSOR gene(TSG) are cancerous when there is loss of function mutation occur.In TSG recessive genes are mutated so when both genes mutated then only capable of forming tumor.

All growth factor related genes must come under PROTO-ONCOGENE and the growth regulator comes under TUMOR SUPRESSOR GENE.

ANS 1..YES ..because it comes under RAS MAPK pathway which are involed in cell proliferation and growth.

2..NO, because Retinoblastoma is inhibitor of CDK s which are responsible for G1 cycle progression.It comes under cell cycle regulation as a result Rb genes are TUMOR SUPRESSOR GENE.

3..NO, because it cannot work independently , regulated by p53 which is a tumor supressor gene.When p53 activates BAX apoptosis occur and when not activates.no apoptosis(means cancer).

4..YES ,it is  PROTO-ONCOGENE,which involved in apoptosis of cell by inhibiting tthe activity of anti apoptotic factors.

5.,NO, it is also a tumor supressor gene ,controlling DNA damage,cell damage through apotosis or CELL CYCLE ARREST.

6.YES , because it involves in cell cycle for growth as CDKs are depends on them directly. eg..cyclin D

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