title: N-acetoxy-N-acetyl-2-aminofluorene-induced mutation spectrum in a human hprt cDNA shuttle vector integrated into mammalian cells.
abstract: The spectrum of mutations induced by N-acetoxy-N-acetyl-2-aminofluorene (N-AcO-AAF) was examined by the pZipHprtNeo shuttle vector in mammalian cells. The vector carries a cDNA of the human hypoxanthine phosphoribosyl transferase (hprt) gene, which is stably integrated into chromosomal DNA of a mouse cell line, VH12. After treatment of the cell with N-AcO-AAF, 48 independent 6-thioguanine-resistant clones were obtained and altered sequences of the mutated cDNA hprt genes were determined. Frameshifts and deletions were the predominant mutational events (68%) induced by N-AcO-AAF and the remainder were base substitutions (32%) of various types. Analysis of sequence alterations at all the sites of mutation revealed that: (i) > 65% of mutations occurred at G:C sites, suggesting C8G adducts are responsible premutagenic lesions for these mutations; and (ii) short sequence repeats were frequently found at the sites of frameshift and deletion, and slippage--misalignment is the suggested mechanism for the induction of mutations at these sites. Implied significance of slippage--misalignment as a fundamental mechanism for mutagenesis is discussed.
authors.affiliation: Department of Applied Chemistry, Faculty of Engineering, Kyushu Institute of Technology, Kitakyushu, Japan.
authors.forename: H I
authors.initials: HI
authors.lastname: Ogawa
authors.forename: H
authors.initials: H
authors.lastname: Kimura
authors.forename: M
authors.initials: M
authors.lastname: Koya
authors.forename: H
authors.initials: H
authors.lastname: Higuchi
authors.forename: T
authors.initials: T
authors.lastname: Kato
mesh_terms: D016475:3T3 Cells; D000099:Acetoxyacetylaminofluorene / Q000633:toxicity*; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D018076:DNA, Complementary / Q000378:metabolism; D016368:Frameshift Mutation; D005822:Genetic Vectors; D006801:Humans; D007041:Hypoxanthine Phosphoribosyltransferase / Q000096:biosynthesis / Q000235:genetics*; D051379:Mice; D008969:Molecular Sequence Data; D005810:Multigene Family; D016296:Mutagenesis; D009153:Mutagens / Q000633:toxicity*; D017354:Point Mutation; D017384:Sequence Deletion; D014162:Transfection
chemical_list: D018076:DNA, Complementary; D009153:Mutagens; D000099:Acetoxyacetylaminofluorene; D007041:Hypoxanthine Phosphoribosyltransferase