RRC ID 4648
Author Salem AM, Nakano T, Takuwa M, Matoba N, Tsuboi T, Terato H, Yamamoto K, Yamada M, Nohmi T, Ide H.
Title Genetic analysis of repair and damage tolerance mechanisms for DNA-protein cross-links in Escherichia coli.
Journal J Bacteriol
Abstract DNA-protein cross-links (DPCs) are unique among DNA lesions in their unusually bulky nature. We have recently shown that nucleotide excision repair (NER) and RecBCD-dependent homologous recombination (HR) collaboratively alleviate the lethal effect of DPCs in Escherichia coli. In this study, to gain further insight into the damage-processing mechanism for DPCs, we assessed the sensitivities of a panel of repair-deficient E. coli mutants to DPC-inducing agents, including formaldehyde (FA) and 5-azacytidine (azaC). We show here that the damage tolerance mechanism involving HR and subsequent replication restart (RR) provides the most effective means of cell survival against DPCs. Translesion synthesis does not serve as an alternative damage tolerance mechanism for DPCs in cell survival. Elimination of DPCs from the genome relies primarily on NER, which provides a second and moderately effective means of cell survival against DPCs. Interestingly, Cho rather than UvrC seems to be an effective nuclease for the NER of DPCs. Together with the genes responsible for HR, RR, and NER, the mutation of genes involved in several aspects of DNA repair and transactions, such as recQ, xth nfo, dksA, and topA, rendered cells slightly but significantly sensitive to FA but not azaC, possibly reflecting the complexity of DPCs or cryptic lesions induced by FA. UvrD may have an additional role outside NER, since the uvrD mutation conferred a slight azaC sensitivity on cells. Finally, DNA glycosylases mitigate azaC toxicity, independently of the repair of DPCs, presumably by removing 5-azacytosine or its degradation product from the chromosome.
Volume 191(18)
Pages 5657-68
Published 2009-9-1
DOI 10.1128/JB.00417-09
PII JB.00417-09
PMID 19617358
PMC PMC2737949
MeSH Azacitidine / pharmacology Cross-Linking Reagents / metabolism* Cross-Linking Reagents / pharmacology DNA Damage / genetics* DNA Glycosylases / genetics DNA Glycosylases / metabolism DNA Repair / genetics* DNA Replication DNA, Bacterial / chemistry DNA, Bacterial / metabolism* Escherichia coli K12 / drug effects Escherichia coli K12 / genetics Escherichia coli K12 / growth & development Escherichia coli K12 / metabolism* Escherichia coli Proteins / chemistry Escherichia coli Proteins / genetics Escherichia coli Proteins / metabolism* Formaldehyde / pharmacology Mutation Protein Binding Recombination, Genetic
IF 3.234
Times Cited 25
Prokaryotes E. coli ME8083 AQ10459 AQ10479