title: Epistasis, photoreactivation and mutagen sensitivity of DNA repair mutants upr-1 and mus-26 in Neurospora crassa.
abstract: Double mutants were constructed combining mus-26, formerly designated uvs-(SA3B), with other UV-sensitive mutants. Tests of sensitivity of these double mutants to UV and to chemical mutagens revealed that mus-26 and upr-1 belong to the same epistatic group. The UV dose-response curve of mus-26 showed a characteristic plateau in the range of 100-200 J/m2. The same characteristic was also shown in the dose-response curves of upr-1 and the double mutant, upr-1 mus-26. Photoreactivation of UV damage in mus-26, upr-1 and upr-1 mus-26 was defective but not null. Assays were made of the reversion rate of ad-8 in strains that also carried UV-sensitive mutations. The reversion frequencies of the strains with upr-1 and upr-1 mus-26 were very low for the UV dose range below 300 J/m2, similarly to mus-26. Previously reported homozygous sterility of mus-26 was not caused by the mus-26 locus itself, and fertile strains were obtained among progeny. The results of this study suggest that mus-26 and upr-1 have similar properties in DNA repair.
authors.affiliation: Department of Regulation Biology, Faculty of Science, Saitama University, Urawa, Japan.
authors.forename: C
authors.initials: C
authors.lastname: Ishii
authors.forename: H
authors.initials: H
authors.lastname: Inoue
mesh_terms: D015112:4-Nitroquinoline-1-oxide / Q000494:pharmacology; D000585:Aminacrine / Q000031:analogs & derivatives / Q000494:pharmacology; D004260:DNA Repair; D004307:Dose-Response Relationship, Radiation; D005720:Gamma Rays; D005838:Genotype; D008741:Methyl Methanesulfonate / Q000494:pharmacology*; D008769:Methylnitronitrosoguanidine / Q000494:pharmacology; D016685:Mitomycin; D008937:Mitomycins / Q000494:pharmacology; D009153:Mutagens / Q000494:pharmacology*; D009154:Mutation; D009491:Neurospora / Q000235:genetics*; D009492:Neurospora crassa / Q000187:drug effects / Q000235:genetics* / Q000528:radiation effects; D009588:Nitrogen Mustard Compounds / Q000494:pharmacology; D014466:Ultraviolet Rays
chemical_list: D008937:Mitomycins; D009153:Mutagens; D009588:Nitrogen Mustard Compounds; D008769:Methylnitronitrosoguanidine; D016685:Mitomycin; D015112:4-Nitroquinoline-1-oxide; D000585:Aminacrine; C004294:acridine half-mustard; D008741:Methyl Methanesulfonate