A compromised yeast RNA polymerase II enhances UV sensitivity in the absence of global genome nucleotide excision repair.
Nucleotide excision repair is the major pathway responsible for removing UV-induced DNA damage, and is therefore essential for cell survival following exposure to UV radiation. In this report, we have assessed the contributions of some components of the RNA polymerase II (Pol II) transcription machinery to UV resistance in Saccharomyces cerevisiae. Deletion of the gene encoding the Pol II elongation factor TFIIS (SII) resulted in enhanced UV sensitivity, but only in the absence of global genome repair dependent on the RAD7 and RAD16 genes, a result seen previously with deletions of RAD26 and RAD28, yeast homologs of the human Cockayne syndrome genes CSB and CSA, respectively. A RAD7/16-dependent reduction in survival after UV irradiation was also seen in the presence of mutations in RNA Pol II that confer a defect in its response to SII, as well as with other mutations which reside in regions of the largest subunit of Pol II not involved in SII interactions. Indeed, an increase in UV sensitivity was achieved by simply decreasing the steadystate level of RNA Pol II. Truncation of the C-terminal domain and other RNA Pol II mutations conferred sensitivity to the ribonucleotide reductase inhibitor hydroxyurea and induction of RNR1 and RNR2 mRNAs after UV irradiation was attenuated in these mutant cells. That UV sensitivity can be a consequence of mutations in the RNA Pol II machinery in yeast cells suggests that alterations in transcriptional programs could underlie some of the pathophysiological defects seen in the human disease Cockayne syndrome.
Banting and Best Department of Medical Research, University of Toronto, Ontario, Canada.
J M
JM
Wong
C J
CJ
Ingles
D000251:Adenosine Triphosphatases; D003057:Cockayne Syndrome / Q000235:genetics; D004260:DNA Repair; D004268:DNA-Binding Proteins; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D017353:Gene Deletion; D016681:Genome, Fungal; D006801:Humans; D006918:Hydroxyurea / Q000494:pharmacology; D021122:Protein Subunits; D012319:RNA Polymerase II / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000235:genetics* / Q000528:radiation effects; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D035165:Transcription Factors, General; D014158:Transcription, Genetic / Q000187:drug effects / Q000528:radiation effects; D035602:Transcriptional Elongation Factors; D014466:Ultraviolet Rays
D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D021122:Protein Subunits; C101960:RAD28 protein, S cerevisiae; C063915:RAD7 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D035165:Transcription Factors, General; D035602:Transcriptional Elongation Factors; C018648:transcription factor S-II; D012319:RNA Polymerase II; D000251:Adenosine Triphosphatases; C075467:RAD16 protein, S cerevisiae; D006918:Hydroxyurea