Question

In DSB repair in G1 phase, which of these factors would be seen which is absent in other phases?

(a) RAD 51

(b) MRN

(c) RAD 23

(d) Ku 70/80

This question was addressed to me in an interview for internship.

This is a very interesting question from Repair of DNA Damage: Recombinational and Bypass topic in division DNA Mutation, DNA Repair, Transposable Elements of Cytogenetics

Answer 1

Correct option is (d) Ku 70/80

For explanation: In G1 phase we have non homologous end joining. In this phase Ku 80/90 hetero dimer senses are repairs the DSB in absence of a homologous chromosome. RAD 51 and MRN are also seen in homologous repair in S or G2 phase, and RAD 23 is needed for NER.