Translesion DNA Synthesis and Mutagenesis in Prokaryotes

The presence of unrepaired lesions in DNA represents a challenge for replication. Most, but not all, DNA lesions block the replicative DNA polymerases. The conceptually simplest procedure to bypass lesions during DNA replication is translesion synthesis (TLS), whereby the replicative polymerase is transiently replaced by a specialized DNA polymerase that synthesizes a short patch of DNA across the site of damage. This process is inherently error prone and is the main source of point mutations. The diversity of existing DNA lesions and the biochemical properties of Escherichia coli DNA polymerases will be presented. Our main goal is to deliver an integrated view of TLS pathways involving the multiple switches between replicative and specialized DNA polymerases and their interaction with key accessory factors. Finally, a brief glance at how other bacteria deal with TLS and mutagenesis is presented.