Analysis of gene- and strand-specific repair in the moderately UV-sensitive Saccharomyces cerevisiae rad23 mutant.
The RAD23 gene of Saccharomyces cerevisiae is involved in nucleotide excision repair (NER) and mutations in this gene confer a moderate sensitivity to UV irradiation. However, no repair of either cyclobutane pyrimidine dimers (CPDs) and 6-4 photoproducts, the major types of lesions formed upon UV irradiation, was detectable during the first 4 h post UV irradiation in a rad23 mutant. rad23, like the rad7 and rad16 mutants, is not as UV sensitive as completely NER-deficient mutants. The rad7 and rad16 mutants are only partly defective in NER: non-transcribed strands are completely refractory to repair while transcription-coupled repair is not affected. To investigate whether the rad23 mutant has similar strand-specific repair characteristics we analyzed gene-specific CPD removal from several loci using strand-specific probes but did not detect any repair. The moderate UV sensitivity of rad23 mutants as compared to completely NER-deficient mutants is therefore not due to gene- or strand-specific removal of lesions, indicating that rad23 mutants do not have a similar repair defect as rad7 or rad16 mutants, but are presumably defective in general NER. The rad23 mutation does not suppress the high UV sensitivity of completely NER-deficient rad1 or rad14 strains. This demonstrates that the relatively high survival of rad23 mutants in not due to an increased tolerance for the lesions that seem to persist in the genome but rather requires some NER function.
Verhage
R A
RA
Laboratory of Molecular Genetics, Leiden Institute of Chemistry, Leiden University, The Netherlands.
Zeeman
A M
AM
Lombaerts
M
M
van de Putte
P
P
Brouwer
J
J
D001483:Base Sequence; D015139:Blotting, Southern; D015342:DNA Probes; D004260:DNA Repair / Q000235:genetics / Q000502:physiology*; D045643:DNA Repair Enzymes; D004262:DNA Restriction Enzymes; D004271:DNA, Fungal / Q000528:radiation effects; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D017353:Gene Deletion; D008969:Molecular Sequence Data; D011740:Pyrimidine Dimers / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000528:radiation effects*; D029701:Saccharomyces cerevisiae Proteins; D035381:TATA-Binding Protein Associated Factors; D035362:Transcription Factor TFIID; D051758:Transcription Factor TFIIH; D014157:Transcription Factors / Q000378:metabolism; D019473:Transcription Factors, TFII; D014466:Ultraviolet Rays
D015342:DNA Probes; D004271:DNA, Fungal; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D011740:Pyrimidine Dimers; C072975:RAD14 protein, S cerevisiae; C490846:RAD23 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C490039:TAF6 protein, S cerevisiae; D035381:TATA-Binding Protein Associated Factors; D035362:Transcription Factor TFIID; D014157:Transcription Factors; D019473:Transcription Factors, TFII; C058406:pyrimidine-pyrimidone dimer; D051758:Transcription Factor TFIIH; D004262:DNA Restriction Enzymes; D045643:DNA Repair Enzymes