title: Sequence analysis of ultraviolet-induced mutations in M13lacZ hybrid phage DNA.
abstract: We have studied the specificity of ultraviolet (u.v.) mutagenesis in single-stranded DNA phage by analyzing u.v.-induced forward mutations in the lac insert of M13mp2 hybrid phage. Sequence analysis of 114 lac mutants derived from u.v.-irradiated phage grown in u.v.-irradiated cells showed that ultraviolet induces mainly single-nucleotide substitutions and deletions in progeny phage DNA. A total of 74% of the single-base substitution mutations occurred at sites of adjacent pyrimidines in the single-stranded DNA, with both T----C and C----T transitions predominating in the u.v. spectrum. Single-nucleotide deletion mutations occurred preferentially in tracts of repeated pyrimidine nucleotides. Tandem, double-base substitutions did not represent a major class of u.v.-induced mutations, but nearly 10% of mutant clones contained multiple, non-tandem nucleotide changes.
mesh_terms: D001483:Base Sequence; D003090:Coliphages / Q000201:enzymology / Q000235:genetics / Q000528:radiation effects*; D004277:DNA, Single-Stranded / Q000235:genetics / Q000528:radiation effects; D004279:DNA, Viral / Q000235:genetics / Q000528:radiation effects*; D005814:Genes, Viral / Q000528:radiation effects; D007763:Lac Operon; D009154:Mutation; D011740:Pyrimidine Dimers / Q000528:radiation effects; D014466:Ultraviolet Rays; D001616:beta-Galactosidase / Q000378:metabolism
chemical_list: D004277:DNA, Single-Stranded; D004279:DNA, Viral; D011740:Pyrimidine Dimers; D001616:beta-Galactosidase