title: DNA polymerase V allows bypass of toxic guanine oxidation products in vivo.
abstract: Reactive oxygen and nitrogen radicals produced during metabolic processes, such as respiration and inflammation, combine with DNA to form many lesions primarily at guanine sites. Understanding the roles of the polymerases responsible for the processing of these products to mutations could illuminate molecular mechanisms that correlate oxidative stress with cancer. Using M13 viral genomes engineered to contain single DNA lesions and Escherichia coli strains with specific polymerase (pol) knockouts, we show that pol V is required for efficient bypass of structurally diverse, highly mutagenic guanine oxidation products in vivo. We also find that pol IV participates in the bypass of two spiroiminodihydantoin lesions. Furthermore, we report that one lesion, 5-guanidino-4-nitroimidazole, is a substrate for multiple SOS polymerases, whereby pol II is necessary for error-free replication and pol V for error-prone replication past this lesion. The results spotlight a major role for pol V and minor roles for pol II and pol IV in the mechanism of guanine oxidation mutagenesis.
authors.affiliation: Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: William L
authors.initials: WL
authors.lastname: Neeley
authors.forename: Sarah
authors.initials: S
authors.lastname: Delaney
authors.forename: Yuriy O
authors.initials: YO
authors.lastname: Alekseyev
authors.forename: Daniel F
authors.initials: DF
authors.lastname: Jarosz
authors.forename: James C
authors.initials: JC
authors.lastname: Delaney
authors.forename: Graham C
authors.initials: GC
authors.lastname: Walker
authors.forename: John M
authors.initials: JM
authors.lastname: Essigmann
mesh_terms: D017104:Bacteriophage M13 / Q000235:genetics; D004261:DNA Replication / Q000235:genetics; D004259:DNA-Directed DNA Polymerase / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D005609:Free Radicals / Q000378:metabolism*; D006146:Guanidines / Q000378:metabolism*; D006147:Guanine / Q000378:metabolism*; D016296:Mutagenesis; D009593:Nitroimidazoles / Q000378:metabolism*; D010084:Oxidation-Reduction
chemical_list: C493908:5-guanidino-4-nitroimidazole; D029968:Escherichia coli Proteins; D005609:Free Radicals; D006146:Guanidines; D009593:Nitroimidazoles; D006147:Guanine; C120926:DNA polymerase V, E coli; D004259:DNA-Directed DNA Polymerase