title: Genetic requirements for frameshift reversion induced by bulky DNA adducts in M13 DNA.
abstract: In order to analyze the genetic requirements and mechanisms of frameshift mutagenesis by activated aflatoxin B1 (AFB1), in vitro-modified phage M13 replicative form (RF) DNA was transfected into appropriate Escherichia coli cells and +1 or -1 frameshift revertants in the lacZ(alpha) gene were isolated. This analysis shows that both +1 and -1 frameshift mutagenesis by AFB1 is significantly reduced in a umuC- background. On the other hand, in the absence of RecA, +1 frameshift mutagenesis is partially reduced, but -1 frameshift mutagenesis is unaffected. DNA sequence analysis of +1 frameshifts induced by AFB1 in recA- cells suggests that the mutations occur at the same sites as in recA+ cells, but that there are significant differences in the specificity of the observed base changes. A model consistent with the observed effects in the absence of RecA suggests that an appreciable fraction of AFB1-adducted guanines can correctly template for a cytosine.
authors.affiliation: Department of Microbiology and Molecular Genetics, University of Medicine, New Jersey Medical School, Newark 07103.
authors.forename: C B
authors.initials: CB
authors.lastname: Bennett
authors.forename: X
authors.initials: X
authors.lastname: Luo
authors.forename: M Z
authors.initials: MZ
authors.lastname: Humayun
mesh_terms: D000818:Animals; D001435:Bacteriophages / Q000378:metabolism*; D001483:Base Sequence; D001711:Biotransformation; D006224:Cricetinae; D004249:DNA Damage; D004279:DNA, Viral / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics; D016368:Frameshift Mutation; D005798:Genes, Bacterial; D008297:Male; D008647:Mesocricetus; D008748:Methylcholanthrene / Q000493:pharmacokinetics; D008969:Molecular Sequence Data; D010957:Plasmids; D011938:Rec A Recombinases / Q000235:genetics / Q000378:metabolism; D013379:Substrate Specificity; D014162:Transfection
chemical_list: D004279:DNA, Viral; D008748:Methylcholanthrene; D011938:Rec A Recombinases