title: Isolation and partial characterization of a mutant of Escherichia coli deficient in DNA polymerase II.
abstract: A mutant of Escherichia coli deficient in DNA polymerase II has been isolated from E. coli polA1 by mutagenesis with N-methyl-N'-nitro-N-nitrosoguanidine and assay of polymerase activity in extracts of survivors. The polA1 mutation was suppressed during mutagenesis by introduction of the suppressor, su7(+), into the parental strain. The mutant, HMS83 polA1 polB1, contains less than 0.5% of the normal levels of DNA polymerase II. The only polymerase activity detected in the mutant is DNA polymerase III. E. coli HMS83 grows normally at both 25 and 42 degrees , and supports the growth of bacteriophages T4, T7, lambda, varphiX174, 186, P2, and fd. The polB mutation does not affect sensitivity to ultraviolet irradiation or recombination frequencies.
mesh_terms: D002458:Cell Fractionation; D002470:Cell Survival / Q000528:radiation effects; D002848:Chromatography, DEAE-Cellulose; D004254:DNA Nucleotidyltransferases / Q000032:analysis* / Q000302:isolation & purification; D004269:DNA, Bacterial / Q000096:biosynthesis*; D004926:Escherichia coli / Q000201:enzymology* / Q000528:radiation effects; D006146:Guanidines / Q000494:pharmacology*; D008320:Maltose / Q000378:metabolism; D008722:Methods; D009153:Mutagens / Q000494:pharmacology; D009154:Mutation / Q000187:drug effects*; D009603:Nitroso Compounds / Q000494:pharmacology*; D009604:Nitrosoguanidines / Q000494:pharmacology; D011506:Proteins / Q000032:analysis; D011830:Radiation Effects; D011995:Recombination, Genetic; D014161:Transduction, Genetic; D014466:Ultraviolet Rays
chemical_list: D004269:DNA, Bacterial; D006146:Guanidines; D009153:Mutagens; D009603:Nitroso Compounds; D009604:Nitrosoguanidines; D011506:Proteins; D008320:Maltose; D004254:DNA Nucleotidyltransferases