Translesion DNA polymerases remodel the replisome and alter the speed of the replicative helicase

• Published in: Proceedings of the National Academy of Sciences - PNAS 2009-04, Vol.106 (15), p.6031-6038
• Main Authors: Indiani, Chiara, Langston, Lance D, Yurieva, Olga, Goodman, Myron F, O'Donnell, Mike
• Format: Article
• Language: English
• Subjects: Biological Sciences; Chromosomes, Bacterial - genetics; DNA; DNA damage; DNA Damage - genetics; DNA Helicases - genetics; DNA Helicases - metabolism; DNA replication; DNA Replication - genetics; DNA, Bacterial - biosynthesis; DNA, Bacterial - genetics; DNA, Bacterial - metabolism; DNA-Directed DNA Polymerase - genetics; DNA-Directed DNA Polymerase - metabolism; Escherichia coli; Escherichia coli - enzymology; Escherichia coli - genetics; Gels; Gene expression regulation; Genes; Genetic SOS response; Lesions; Mutagenesis; Time Factors
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.0901403106

All cells contain specialized translesion DNA polymerases that replicate past sites of DNA damage. We find that Escherichia coli translesion DNA polymerase II (Pol II) and polymerase IV (Pol IV) function with DnaB helicase and regulate its rate of unwinding, slowing it to as little as 1 bp/s. Furthermore, Pol II and Pol IV freely exchange with the polymerase III (Pol III) replicase on the β-clamp and function with DnaB helicase to form alternative replisomes, even before Pol III stalls at a lesion. DNA damage-induced levels of Pol II and Pol IV dominate the clamp, slowing the helicase and stably maintaining the architecture of the replication machinery while keeping the fork moving. We propose that these dynamic actions provide additional time for normal excision repair of lesions before the replication fork reaches them and also enable the appropriate translesion polymerase to sample each lesion as it is encountered.