title: Processing of MucA protein is required for spontaneous and benzo[a]pyrene-induced reversion of the Escherichia coli trpA23 missense mutation by G.C-T.A transversions: effect of a deficiency in the MutY DNA glycosylase.
abstract: We have studied the influence of the processing of MucA protein on the occurrence of base substitution mutations. Escherichia coli strains carrying the trpA23 missense mutation and having a full deletion of the chromosomal umuD/C operon were transformed with plasmids encoding the MucB protein together with either wild-type MucA or the nonprocessable MucA202 protein. The efficient reversion of the trpA23 allele by G.C-T.A transversions in benzo[a]pyrene (B[a]P)-treated cells required the function of a matured MucA protein. This processed protein was also necessary for the occurrence of G.C-T.A transversions targeted at spontaneous DNA lesions and for the SOS mutator effect dependent on the constitutive coprotease activity of the RecA730 protein. In contrast, G.C-T.A transversions reverting trpA23 were spontaneously generated by an SOS-independent mechanism in cells deficient in the MutY DNA glycosylase.
authors.affiliation: Instituto de Investigaciones Citológicas, Fundación Valenciana de Investigaciones Biomédicas, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Urios
authors.forename: G
authors.initials: G
authors.lastname: Herrera
authors.forename: V
authors.initials: V
authors.lastname: Aleixandre
authors.forename: M
authors.initials: M
authors.lastname: Blanco
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism*; D001564:Benzo(a)pyrene / Q000633:toxicity; D001711:Biotransformation; D045647:DNA Glycosylases; D004260:DNA Repair; D004926:Escherichia coli / Q000235:genetics; D009153:Mutagens / Q000378:metabolism*; D009699:N-Glycosyl Hydrolases / Q000378:metabolism*; D010447:Peptide Hydrolases / Q000378:metabolism; D017354:Point Mutation; D011499:Protein Processing, Post-Translational; D011938:Rec A Recombinases / Q000378:metabolism; D013014:SOS Response, Genetics; D013489:Suppression, Genetic / Q000235:genetics*; D014367:Tryptophan Synthase / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; C063757:MucA protein, Bacteria; D009153:Mutagens; D001564:Benzo(a)pyrene; D011938:Rec A Recombinases; D045647:DNA Glycosylases; D009699:N-Glycosyl Hydrolases; C061738:mutY adenine glycosylase; D010447:Peptide Hydrolases; D014367:Tryptophan Synthase