title: The isfA mutation inhibits mutator activity and processing of UmuD protein in Escherichia coli recA730 strains.
abstract: Further studies on the isfA mutation responsible for anti-SOS and antimutagenic activities in Escherichia coli are described. We have previously shown that the isfA mutation inhibits mutagenesis and other SOS-dependent phenomena, possibly by interfering with RecA coprotease activity. The isfA mutation has now been demonstrated also to suppress mutator activity in E. coli recA730 and recA730 lexA51(Def) strains that constitutively express RecA coprotease activity. We further show that the antimutator activity of the isfA mutation is related to inhibition of RecA coprotease-dependent processing of UmuD. Expression of UmuD' from plasmid pGW2122 efficiently restores UV-induced mutagenesis in the recA730 isfA strain and partially restores its mutator activity. On the other hand, overproduction of UmuD'C proteins from pGW2123 plasmid markedly enhances UV sensitivity with no restoration of mutability.
authors.affiliation: Institute of Biochemistry and Biophysics, Polish Academy of Science, Warsaw, Poland.
authors.forename: A
authors.initials: A
authors.lastname: Bebenek
authors.forename: I
authors.initials: I
authors.lastname: Pietrzykowska
mesh_terms: D016587:Antimutagenic Agents / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D015153:Blotting, Western; D004259:DNA-Directed DNA Polymerase; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D029968:Escherichia coli Proteins; D015964:Gene Expression Regulation, Bacterial; D005799:Genes, Dominant / Q000235:genetics; D005838:Genotype; D007763:Lac Operon / Q000235:genetics; D009154:Mutation; D011499:Protein Processing, Post-Translational; D011938:Rec A Recombinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D013014:SOS Response, Genetics / Q000235:genetics*; D014364:Tryptophan / Q000378:metabolism; D014466:Ultraviolet Rays; D001616:beta-Galactosidase / Q000235:genetics / Q000378:metabolism
chemical_list: D016587:Antimutagenic Agents; D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D014364:Tryptophan; D011938:Rec A Recombinases; D004259:DNA-Directed DNA Polymerase; C055218:UmuD protein, E coli; D001616:beta-Galactosidase