RAD6+ gene of Saccharomyces cerevisiae codes for two mutationally separable deoxyribonucleic acid repair functions.
The response of two mutant alleles of the RAD6+ gene of Saccharomyces cerevisiae to the ochre translational suppressor SUQ5 was determined. Both the ultraviolet sensitivity phenotype and the deficiency in ultraviolet-induced mutagenesis phenotype of the rad6-1 allele were suppressed in a [psi+] background. For the rad6-3 allele, only the ultraviolet-sensitivity phenotype was suppressible in a [psi+] background. An SUQ5 rad6-3 [psi+] strain that was examined showed the normal rad6-3 deficiency in ultraviolet-induced mutagenesis. We propose that the RAD6+ gene is divided into two cistrons, RAD6A and RAD6B. RAD6A codes for an activity responsible for the error-prone repair of ultraviolet-induced lesions in deoxyribonucleic acid but is not involved in a cell's resistance to the lethal effects of ultraviolet light. RAD6B codes for an activity essential for error-free repair of potentially lethal mutagenic damage.
D000483:Alleles; D004260:DNA Repair; D005800:Genes, Fungal; D009154:Mutation; D010641:Phenotype; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D013489:Suppression, Genetic; D014466:Ultraviolet Rays