translesion synthesis

Translesion synthesis (TLS) is a DNA repair mechanism that allows cells to replicate DNA even when there are damaged bases present. Normally, DNA replication proceeds smoothly, but when damage occurs, it can block the replication machinery. Instead of halting replication entirely, which can lead to cell death, TLS allows a special type of DNA polymerase to bypass the damaged site.1

This bypass mechanism is often error-prone, meaning it can introduce mutations into the DNA sequence. However, it is considered a crucial survival strategy, as it prevents the complete cessation of DNA replication. TLS is distinct from other repair pathways like base excision repair, which aims to fix the damage before replication occurs.12