title: Proofreading deficiency of Pol I increases the levels of spontaneous rpoB mutations in E. coli.
abstract: The fidelity role of DNA polymerase I in chromosomal DNA replication in E. coli was investigated using the rpoB forward target. These experiments indicated that in a strain carrying a proofreading-exonuclease-defective form of Pol I (polAexo mutant) the frequency of rpoB mutations increased by about 2-fold, consistent with a model that the fidelity of DNA polymerase I is important in controlling the overall fidelity of chromosomal DNA replication. DNA sequencing of rpoB mutants revealed that the Pol I exonuclease deficiency lead to an increase in a variety of base-substitution mutations. A polAexo mutator effect was also observed in strains defective in DNA mismatch repair and carrying the dnaE915 antimutator allele. Overall, the data are consistent with a proposed role of Pol I in the faithful completion of Okazaki fragment gaps at the replication fork.
authors: Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5A, 02-106 Warsaw, Poland.
authors: K
authors: K
authors: Makiela-Dzbenska
authors: P
authors: P
authors: Jonczyk
authors: R M
authors: RM
authors: Schaaper
authors: I J
authors: IJ
authors: Fijalkowska
mesh_terms: D004247:DNA; D053843:DNA Mismatch Repair; D004256:DNA Polymerase I / Q000235:genetics*; D004261:DNA Replication; D004269:DNA, Bacterial; D012321:DNA-Directed RNA Polymerases; D024881:Drug Resistance, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics*; D029968:Escherichia coli Proteins / Q000009:adverse effects* / Q000235:genetics*; D009154:Mutation; D012293:Rifampin / Q000494:pharmacology
chemical_list: D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; C022262:Okazaki fragments; C540081:rpoB protein, E coli; D004247:DNA; D012321:DNA-Directed RNA Polymerases; D004256:DNA Polymerase I; D012293:Rifampin