DNA Damage Response Flashcards Preview

Molecular Biology > DNA Damage Response > Flashcards

Flashcards in DNA Damage Response Deck (17):
1

during replication, a lesion occurs, DNA polymerase cannot continue

Fork reversal occurs, fixing strand with the ssDNA repair pathway

2

for stabilization during fork reversal

RPA (ss binding protein)
9-1-1 complex (trimeric clamp)
special clamp loader

3

PCNA is a

homotrimer, 3 parts, all the same

4

9-1-1 is a

heterotrimer,
3 parts, all different
named for 3 yeast genes, RAD9-RAD1-HUS1

5

PCNA is loaded by

pentameric clamp loader
RFC1-5

6

clamp loader for 9-1-1 complex

has 4 subunits
plus fifth one called Rad17

7

9-1-1 clamp loader finds

ds-ss junction with 5' open end

8

presence of 9-1-1 and RPA coated ss

sends a signal to protein kinase ATR

9

ATR binds to

ATRIP, which connects to RPA
ATR phosphorylates Chk1, which stops DNA replication

10

For double-stranded breaks,

H2AX histone, has SQ in tail
S becomes phosphorylated upon ds break
phosphorylation occurs for a long distance from the break

11

phosphorylated H2AX is called

gammaH2AX

12

after H2AX is phosphorylated

bridge is built connecting broken ends
MRN complex
held together by Zn

13

p53 has 3 important roles

transcription factor, promotes the expression of genes that alter the cell
controls whether the cell will arrest the cell cycle or go into apoptosis
tumor suppressor gene, found mutated in half of all solid tumors

14

genes that promote the growth of tumor cells

oncogenes

15

p53 acts as transcription factor for

p21, an inhibitor protein
stops DNA replication

16

what activates p53 and phosphorylates it

ATM, ATR, Chk1, and Chk2

17

Mdm2

degrades p53