L3: DNA Repair and senescence Flashcards
1
Q
During excision base repair, what recognises the damaged base?
A
DNA glycosylase
2
Q
When DNA glycosylase recognises the damaged base what how does it respond?
A
bends the DNA to flip out the base which is cleaved to leave an APurinic or APyrimidinic (AP) site.
3
Q
What recognises theAPurinic or APyrimidinic (AP) site and what does it do at the site?
A
An endonuclease recognises this site and cleaves the sugar phosphate backbone.
4
Q
When endonuclease recognises the Apurinic or APyrimidinic
(AP) site is cleaves the sugar phosphate back bone. What binds to the cleaved area/the nick? What else happens?
A
PARP (poly ADP ribose polymerase) binds to nick and recruits XRCC1-DNA Pol b complex to replace missing nucleotide, and the nick is sealed by DNA ligase III.
