Single d(ApG)/cis-diamminedichloroplatinum(II) adduct-induced mutagenesis in Escherichia coli.
The mutation spectrum induced by the widely used antitumor drug cis-diamminedichloroplatinum(II) (cis-DDP) showed that cisDDP[d(ApG)] adducts, although they account for only 25% of the lesions formed, are approximately 5 times more mutagenic than the major GG adduct. We report the construction of vectors bearing a single cisDDP[d(ApG)] lesion and their use in mutagenesis experiments in Escherichia coli. The mutagenic processing of the lesion is found to depend strictly on induction of the SOS system of the bacterial host cells. In SOS-induced cells, mutation frequencies of 1-2% were detected. All these mutations are targeted to the 5' base of the adduct. Single A----T transversions are mainly observed (80%), whereas A----G transitions account for 10% of the total mutations. Tandem base-pair substitutions involving the adenine residue and the thymine residue immediately 5' to the adduct occur at a comparable frequency (10%). No selective loss of the strand bearing the platinum adduct was seen, suggesting that, in vivo, cisDDP[d(ApG)] adducts are not blocking lesions. The high mutation specificity of cisDDP[d(ApG)]-induced mutagenesis is discussed in relation to structural data.
Groupe de Cancérogénèse, Institut de Biologie Moleculaire et Cellulaire, Centre National de la Recherche Scientifique, Strasbourg. France.
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D
Burnouf
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C
Gauthier
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JC
Chottard
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RP
Fuchs
D001482:Base Composition; D001483:Base Sequence; D002945:Cisplatin / Q000494:pharmacology*; D003062:Codon / Q000235:genetics; D015226:Dinucleoside Phosphates / Q000494:pharmacology*; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics*; D005822:Genetic Vectors; D008969:Molecular Sequence Data; D009154:Mutation; D015345:Oligonucleotide Probes / Q000138:chemical synthesis; D010641:Phenotype; D010957:Plasmids / Q000187:drug effects; D013014:SOS Response, Genetics; D014169:Transformation, Bacterial
D003062:Codon; D015226:Dinucleoside Phosphates; D015345:Oligonucleotide Probes; C065401:cisplatin-deoxy(adenosine monophosphate guanosine) adduct; D002945:Cisplatin