title: Mutagenesis in UV-irradiated simian virus 40 occurs predominantly at pyrimidine doublets.
abstract: Phenotypic wild-type revertants from a UV-irradiated temperature-sensitive late mutant (ts BC245) of simian virus 40 (SV40) were isolated after replication in monkey cells at the nonpermissive temperature. The mutations occurring in 7 revertants were identified by DNA sequence analysis of the entire gene involved. All 10 mutations identified constituted single base substitutions, 7 of which occurred opposite pyrimidine doublets. Transitions were 3 times more abundant than transversions. Three base changes did not occur opposite pyrimidine-pyrimidine sequences. Exchange of a DNA fragment harbouring the altered base from a revertant with the corresponding fragment from the parental virus, showed that the base substitution was indeed responsible for the reversions to the wild-type phenotype (growth at the restrictive temperature). The data suggest that most base substitutions in highly UV-irradiated simian virus 40 are targeted at sites comprising two adjacent pyrimidines.
authors.forename: H
authors.initials: H
authors.lastname: Braggaar
authors.forename: J J
authors.initials: JJ
authors.lastname: Cornelis
authors.forename: J L
authors.initials: JL
authors.lastname: van der Lubbe
authors.forename: A J
authors.initials: AJ
authors.lastname: van der Eb
mesh_terms: D000818:Animals; D001483:Base Sequence; D002478:Cells, Cultured; D004262:DNA Restriction Enzymes; D004279:DNA, Viral / Q000235:genetics / Q000528:radiation effects*; D000882:Haplorhini; D009154:Mutation / Q000528:radiation effects*; D011740:Pyrimidine Dimers; D013539:Simian virus 40 / Q000235:genetics*; D014466:Ultraviolet Rays
chemical_list: D004279:DNA, Viral; D011740:Pyrimidine Dimers; D004262:DNA Restriction Enzymes