title: Mismatch-induced lethality due to a defect in Escherichia coli RecQ helicase in exonuclease-deficient background: Dependence on MutS and UvrD functions.
abstract: Escherichia coli DNA-unwinding protein RecQ has roles in the regulation of general recombination and the processing of stalled replication forks. In this study, we found that knockout of the recQ gene in combination with xonA xseA recJ mutations, which inhibit methyl-directed mismatch repair (MMR), caused about 100-fold increase in sensitivity to a purine analog 2-aminopurine (2AP). Intriguingly, inactivation of a MMR initiator due to the either mutation mutS or uvrD completely suppressed the 2AP sensitivity caused by recQ xonA xseA recJ mutations, suggesting that RecQ helicase might act on the DNA structures that are generated by the processing of DNA by the MutSLH complex and UvrD helicase. Moreover, the recQ gene knockout in combination with xonA xseA recJ mutations enhanced 2AP-induced filament formation, and increased by twofold the rate of spontaneous forward mutations in the thyA locus but did not increase the rate of rifampicin-resistant mutations. We discuss about the possible interplay between E. coli RecQ helicase and mismatch recognition factors.
authors.affiliation: Department of Biological Functions and Engineering, Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology, 2-4 Hibikino, Wakamatsu-ku, Kita-Kyushu 808-0196, Japan.
authors.forename: Yoshimasa
authors.initials: Y
authors.lastname: Yamana
authors.forename: Shuji
authors.initials: S
authors.lastname: Sonezaki
authors.forename: Hiroaki I
authors.initials: HI
authors.lastname: Ogawa
authors.forename: Kohji
authors.initials: K
authors.lastname: Kusano
mesh_terms: D015075:2-Aminopurine / Q000494:pharmacology; D020137:Base Pair Mismatch / Q000187:drug effects / Q000235:genetics*; D001483:Base Sequence; D004265:DNA Helicases / Q000378:metabolism*; D004926:Escherichia coli / Q000166:cytology / Q000187:drug effects / Q000201:enzymology* / Q000254:growth & development; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D005090:Exodeoxyribonucleases / Q000172:deficiency* / Q000235:genetics; D008957:Models, Genetic; D008969:Molecular Sequence Data; D051719:MutS DNA Mismatch-Binding Protein / Q000378:metabolism*; D009154:Mutation / Q000235:genetics; D053484:RecQ Helicases / Q000235:genetics* / Q000378:metabolism; D017422:Sequence Analysis, DNA
chemical_list: D029968:Escherichia coli Proteins; D015075:2-Aminopurine; D005090:Exodeoxyribonucleases; C489467:RecJ protein, E coli; C506724:RecQ protein, E coli; C506746:UvrD protein, E coli; D051719:MutS DNA Mismatch-Binding Protein; C497175:MutS protein, E coli; D004265:DNA Helicases; D053484:RecQ Helicases