title: Mutant pso8-1 of Saccharomyces cerevisiae, sensitive to photoactivated psoralens, UV radiation, and chemical mutagens, contains a rad6 missense mutant allele.
abstract: A novel mutant isolate of Saccharomyces cerevisiae, sensitive to photoactivated mono- and bi-functional psoralens, to UV at 254 nm (UVC), and to nitrosoguanidine, was found to complement the photoactivated psoralen-sensitivity phenotype conferred by the pso1- pso7 mutations and was therefore named pso8-1. A constructed pso8-1 rad4-4 double mutant was super-sensitive to UVC, thus indicating a synergistic interaction of the two mutant alleles. Molecular cloning via complementation of the pso8 mutant's sensitivity phenotype and genetic studies revealed that pso8 is allelic to RAD6. While a pso8-1 mutant had low mutagen-induced mutability, homoallelic diploids showed nearly wild-type sporulation. Sequence analysis of the mutant allele showed pso8-1 to contain a novel, hitherto undescribed T-->C transition in nucleotide position 191, leading to a substitution by leucine of a highly conserved proline at position 64, Rad6-[P64L], which may have severe consequences for the tertiary structure (and hence binding to Rad18p) of the mutant protein.
authors.affiliation: Departamento de Biofísica/Centro de Biotecnologia, UFRGS, Av. Bento Gonçalves 9500, Porto Alegre, Rio Grande do Sul, Brazil.
authors.forename: H
authors.initials: H
authors.lastname: Rolla
authors.forename: M
authors.initials: M
authors.lastname: Grey
authors.forename: C L
authors.initials: CL
authors.lastname: Schmidt
authors.forename: E
authors.initials: E
authors.lastname: Niegemann
authors.forename: M
authors.initials: M
authors.lastname: Brendel
authors.forename: J A P
authors.initials: JA
authors.lastname: Henriques
mesh_terms: D000483:Alleles; D000595:Amino Acid Sequence; D017124:Conserved Sequence; D011564:Furocoumarins / Q000494:pharmacology*; D005800:Genes, Fungal; D008769:Methylnitronitrosoguanidine / Q000494:pharmacology; D008969:Molecular Sequence Data; D009153:Mutagens / Q000494:pharmacology; D020125:Mutation, Missense; D010641:Phenotype; D010777:Photochemistry; D017319:Photosensitizing Agents / Q000494:pharmacology*; D010802:Phylogeny; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000235:genetics* / Q000528:radiation effects; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D014466:Ultraviolet Rays
chemical_list: D011564:Furocoumarins; D009153:Mutagens; D017319:Photosensitizing Agents; D029701:Saccharomyces cerevisiae Proteins; D008769:Methylnitronitrosoguanidine