7.4 Proto-oncogenes and Tumor Supressors Part 2

Question 1

What doe the TP53 gene encode for?

Answer 1

p53 transcription factor

Question 2

What is the p53 protein responsible for?

Answer 2

control of transcription of more than 50 different genes

Question 3

How is p53 found normally in cells?

Answer 3

at low levels bound to MdM2

Question 4

What is the purpose of MDM2?

Answer 4

since p53 is continuously transcribed by the cell MDM2 will bind to it an send it for degradation; represses the protein product

Question 5

When is MDM2 stimulated to release p53 and allow it to become activated?

Answer 5

when cellular stress induces DNA damage

Question 6

How is p53 activated?

Answer 6

phosphorylation or acetylation

Question 7

What genes does p53 stimulate the expression of?

Answer 7

those involved in arrest of cell cycle checkpoints, stimulation of apoptosis, and DNA repair

Question 8

What stimulates the expression of the MDM2 gene?

Answer 8

activated p53 causing a negative feedback loop

Question 9

What do the vast majority of mutations in the p53 lead to?

Answer 9

inactivation of p53 so it cannot help with DNA repair, cell cycle checkpoints, or initiation of cell death

Question 10

What do some gain of function mutations in p53 lead to?

Answer 10

genome wide chromatin modifications by modifying histone proteins

Question 11

What is dubbed the guardian of the genome?

Answer 11

p53