DS break repair

Question 1

what recognizes DS breaks

Answer 1

PIKKs family (ATm and ATR

Question 2

which pathway gives protection of DNA ends and which has end resection

Answer 2

NHEJ protects and HR resects

Question 3

what proteins are required for resistance to ionizing radiation and VDJ recombination

Answer 3

NHEJ proteins

Question 4

when does NHEJ occur

Answer 4

any time

Question 5

which pathway is sequence independent

Answer 5

NHEJ

Question 6

when does HR occur

Answer 6

right after DNA replication aka S and G2

Question 7

what does HR require

Answer 7

nearly identical DNA strands

Question 8

steps in HR

Answer 8

1. broken ends resected 2. SS invade homologous DNA 3, cross over resolved to 2 separate DNA strands

Question 9

different resolution of holiday junctions can cause 2 types of genetic exchanges

Answer 9

gene conversion or crossing over

Question 10

what can happen with HR

Answer 10

LOH (loss of heterozygosity)

Question 11

name 2 proteins that are important to determine if NHEJ or HR occurs

Answer 11

BRCA 1 and 53 BP1

Question 12

what is BRCA the target of

Answer 12

phosphorylation by activated ATM and ATR- they phosphorylate it when they need to recruit it to a double stranded break

Question 13

proper control of BRC1 is required for what

Answer 13

HR

Question 14

53BP1 is a positive regulator of what by doing what

Answer 14

NHEJ by promoting the synapsis of distal broken ends and by antagonizing their resection

Question 15

without HR mediated by BRCA1, 53BP1 promotes what

Answer 15

deleterious NHEJ

Question 16

BRCA and 53BP1 _____ to determine the correct DNA ds break repair pathway

Answer 16

compete

Question 17

translocations most often occur when DNA DSBs are healed

Answer 17

between different chromosomes by NHEJ

Question 18

what happens if a DNA DSB doenst get fixed

Answer 18

cell death