Question

Fill in the blank with the repair pathway(s) (NER, BER, MMR, Photolyase, Translesion Synthesis) that could repair the following types of damage. Note: There is a glycosylase that recognizes oxidized guanine. Oxidized guanine (GO) T-T dimers Cytosine deamination Replication slippage Replication blockage

Answer 1

Ans:- Oxidized gauanine (GO) - BER , BER is base excision repair mechanism involves 8-oxoguanine glycosulase which identify and locate oxidized guanine and remove it to repair DNA damage.

T-T dimers - Photolyase, T-T dimers (also called pyrimidine dimers) is thymine dimer cause by exposure of DNA to UV light. T-T dimers cause inhibition of replication and transcription. photolyase is photoreactivating enzyme which heal T-T dimers.

Cytosine deamination- NER, deamination of cytosine convert it into uracil. which removed and repair by NER

Replication slippage:- MMR, mismatch repair cause loop in DNA strand which removed by DNA polymerase and strand sealed by ligase.

Replication blockage:-Translesion synthesis, translesion synthesis is mechanism by which it allow dna strand to remove blockage on replication.