title: Evidence for Escherichia coli polymerase II mutagenic bypass of intrastrand DNA crosslinks.
abstract: The mutagenic potentials of DNAs containing site- and stereospecific intrastrand DNA crosslinks were evaluated in Escherichia coli cells that contained a full complement of DNA polymerases or were deficient in either polymerases II, IV, or V. Crosslinks were made between adjacent N(6)-N(6) adenines and consisted of R,R- and S,S-butadiene crosslinks and unfunctionalized 2-, 3-, and 4-carbon tethers. Although replication of single-stranded DNAs containing the unfunctionalized 3- and 4-carbon tethers were non-mutagenic in all strains tested, replication past all the other intrastrand crosslinks was mutagenic in all E. coli strains, except the one deficient in polymerase II in which no mutations were ever detected. However, when mutagenesis was analyzed in cells induced for SOS, mutations were not detected, suggesting a possible change in the overall fidelity of polymerase II under SOS conditions. These data suggest that DNA polymerase II is responsible for the in vivo mutagenic bypass of these lesions in wild-type E. coli.
authors.affiliation: Sealy Center for Molecular Science, University of Texas Medical Branch, Galveston, 77550, USA.
authors.forename: Manorama
authors.initials: M
authors.lastname: Kanuri
authors.forename: Lubomir V
authors.initials: LV
authors.lastname: Nechev
authors.forename: Sarah E
authors.initials: SE
authors.lastname: Kiehna
authors.forename: Pamela J
authors.initials: PJ
authors.lastname: Tamura
authors.forename: Constance M
authors.initials: CM
authors.lastname: Harris
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Harris
authors.forename: R Stephen
authors.initials: RS
authors.lastname: Lloyd
mesh_terms: D004247:DNA / Q000096:biosynthesis / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D004257:DNA Polymerase II / Q000378:metabolism*; D004261:DNA Replication; D004852:Epoxy Compounds / Q000494:pharmacology; D004926:Escherichia coli / Q000201:enzymology*; D016296:Mutagenesis; D014170:Transformation, Genetic
chemical_list: D004852:Epoxy Compounds; C007366:diepoxybutane; D004247:DNA; D004257:DNA Polymerase II