G oncogenic retroviruses

Question 1

proto-oncogenes

Answer 1

normal cellular genes that encode proteins involved in cell communication and regulation of replication

Question 2

viral oncogenes

Answer 2

are pro to-oncogenes that have been incorporated in viral genome. virus infects cells and viral oncogenes produces uncontrolled growth of that cell

Question 3

2 types of retroviruses

Answer 3

acute transforming oncogenic retroviruses and non transforming

Question 4

acute transforming oncogenic retroviruses

Answer 4

highly carcinogenic. cause malignancy in 100% of infected in few days.

Question 5

e.g. of acute transforming oncogenic retroviruses

Answer 5

Rous sarcoma virus infects birds, the genome includes src which is a viral oncogene that causes sarcoma

Question 6

non transforming oncogenic retroviruses

Answer 6

less carcinogenic, not all infected get cancer, takes longer. genome doesn’t encode oncogenes. now wt they produce timor is by insertional activation. for e.g. promotor insertion. expression of host pro to-oncogenec is no longer regulated by host cell