Question

Which of the following mechanisms of mutagenesis via AID activity is possible?

A. The lesion is not repaired prior to replication, resulting in a CG?TA transition.
B. Base excision repair, followed by error-prone DNA polymerase fill-in of the gap created.
C. Mismatch repair, followed by error-prone DNA polymerase fill-in of the gap created.
D. Choices A and B are both possible.
E. All of the above are possible.

Answer 1

The possible mechanisms of mutagenesis via AID activity include the lesion not being repaired prior to replication, base excision repair followed by error-prone DNA polymerase fill-in of the gap, and mismatch repair followed by error-prone DNA polymerase fill-in of the gap.

Step-by-step explanation:

The possible mechanism of mutagenesis via AID activity includes:

Choice A: The lesion is not repaired prior to replication, resulting in a CG→TA transition. This means that the damaged DNA is replicated without being repaired, leading to a change in the nucleotide sequence. An example of this is the formation of pyrimidine dimers due to UV radiation, which can lead to CG→TA transitions.

Choice B: Base excision repair, followed by error-prone DNA polymerase fill-in of the gap created. In this mechanism, damaged bases are recognized and removed by DNA glycosylases through base excision repair. After the damaged base is removed, an error-prone DNA polymerase fills in the gap with nucleotides. This can introduce mutations during replication.

Choice C: Mismatch repair, followed by error-prone DNA polymerase fill-in of the gap created. Mismatch repair is a process that corrects mismatches in the DNA sequence after replication. However, if the repair is not accurate, an error-prone DNA polymerase can introduce mutations during the fill-in of the gap created.

Therefore, choices A, B, and C are all possible mechanisms of mutagenesis via AID activity.