When does base/nucleotide excision repair primarily occur?

Base and nucleotide excision repair are crucial DNA repair mechanisms that address various types of DNA damage, such as those caused by UV light or chemical exposure. Nucleotide excision repair (NER) primarily recognizes and removes bulky lesions, while base excision repair (BER) specifically targets non-helix-distorting base damage.

This repair process primarily occurs before DNA replication. The rationale for this is that if damaged DNA were to be replicated, the errors could become fixed in the genome, leading to mutations that could have harmful consequences for the cell. Repairing DNA before the replication process allows for the maintenance of genetic fidelity and ensures that the newly synthesized DNA strands are accurate.

While repairs can occur during transcription or after replication, the primary phase for excision repair is before replication to ensure that any potential errors are corrected prior to the duplication of the genetic material. Post-translational modification does not relate to DNA repair processes, as it involves the modification of proteins after their synthesis rather than DNA.