title: Multiple pathways for SOS-induced mutagenesis in Escherichia coli: an overexpression of dinB/dinP results in strongly enhancing mutagenesis in the absence of any exogenous treatment to damage DNA.
abstract: dinP is an Escherichia coli gene recently identified at 5.5 min of the genetic map, whose product shows a similarity in amino acid sequence to the E. coli UmuC protein involved in DNA damage-induced mutagenesis. In this paper we show that the gene is identical to dinB, an SOS gene previously localized near the lac locus at 8 min, the function of which was shown to be required for mutagenesis of nonirradiated lambda phage infecting UV-preirradiated bacterial cells (termed lambdaUTM for lambda untargeted mutagenesis). A newly constructed dinP null mutant exhibited the same defect for lambdaUTM as observed previously with a dinB::Mu mutant, and the defect was complemented by plasmids carrying dinP as the only intact bacterial gene. Furthermore, merely increasing the dinP gene expression, without UV irradiation or any other DNA-damaging treatment, resulted in a strong enhancement of mutagenesis in F'lac plasmids; at most, 800-fold increase in the G6-to-G5 change. The enhanced mutagenesis did not depend on recA, uvrA, or umuDC. Thus, our results establish that E. coli has at least two distinct pathways for SOS-induced mutagenesis: one dependent on umuDC and the other on dinB/P.
authors.affiliation: Division of Genetics and Mutagenesis, National Institute of Health Sciences, Setagaya-ku, Tokyo 158, Japan.
authors.forename: S R
authors.initials: SR
authors.lastname: Kim
authors.forename: G
authors.initials: G
authors.lastname: Maenhaut-Michel
authors.forename: M
authors.initials: M
authors.lastname: Yamada
authors.forename: Y
authors.initials: Y
authors.lastname: Yamamoto
authors.forename: K
authors.initials: K
authors.lastname: Matsui
authors.forename: T
authors.initials: T
authors.lastname: Sofuni
authors.forename: T
authors.initials: T
authors.lastname: Nohmi
authors.forename: H
authors.initials: H
authors.lastname: Ohmori
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics*; D001483:Base Sequence; D004249:DNA Damage; D004269:DNA, Bacterial / Q000235:genetics; D004259:DNA-Directed DNA Polymerase; D004926:Escherichia coli / Q000235:genetics*; D029968:Escherichia coli Proteins; D015870:Gene Expression; D005798:Genes, Bacterial; D005816:Genetic Complementation Test; D016296:Mutagenesis; D010957:Plasmids / Q000235:genetics; D011401:Promoter Regions, Genetic; D013014:SOS Response, Genetics / Q000235:genetics*
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; C094399:DinB protein, E coli; D029968:Escherichia coli Proteins; C078202:UmuC protein, E coli; D004259:DNA-Directed DNA Polymerase; C055218:UmuD protein, E coli