title: Spectrum of spontaneous mutation at the APRT locus of Chinese hamster ovary cells: an analysis at the DNA sequence level.
abstract: The spectrum of spontaneous mutation of an endogenous mammalian cell gene has been determined at the DNA sequence level. Thirty independent spontaneous APRT- mutations were cloned and subsequently completely sequenced. Twenty-seven contained single base substitutions. Of these, 22 were G.C to A.T transitions, suggesting a major role for the deamination of cytosine in spontaneous mutagenesis of Chinese hamster ovary cells. The remaining mutants included a tandem double substitution, a -1 frameshift, and a 17-base-pair deletion flanked by a 2-base-pair direct repeat. Many of the independently recovered mutants were clustered at sites of multiple occurrence (hot spots). One site accounted for greater than 25% of all independently recovered events. Mutations were generally located within the coding sequence, although two mutations occurred within the consensus sequence for a 3' splice site.
authors: York University, Department of Biology, North York, ON, Canada.
authors: P J
authors: PJ
authors: de Jong
authors: A J
authors: AJ
authors: Grosovsky
authors: B W
authors: BW
authors: Glickman
mesh_terms: D000228:Adenine Phosphoribosyltransferase / Q000235:genetics*; D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D002872:Chromosome Deletion; D003001:Cloning, Molecular; D006224:Cricetinae; D003412:Cricetulus; D005260:Female; D005796:Genes; D008969:Molecular Sequence Data; D009154:Mutation; D010053:Ovary; D010430:Pentosyltransferases / Q000235:genetics*
chemical_list: D010430:Pentosyltransferases; D000228:Adenine Phosphoribosyltransferase