title: Identification and characterization of CRT10 as a novel regulator of Saccharomyces cerevisiae ribonucleotide reductase genes.
abstract: The CRT10 gene was identified through screening of the Saccharomyces cerevisiae deletion library for hydroxyurea (HU) resistance. CRT10 encodes a putative 957 amino acid, 110 kDa protein with a leucine repeat and a WD40 repeat near the N-terminus. Deletion of CRT10 resulted in an enhanced resistance to HU reminiscent of the inactivation of two other ribonucleotide reductase (Rnr) suppressors, CRT1 and SML1, which regulate Rnr activity at transcriptional and translational levels, respectively. Epistatic analysis indicates that CRT10 belongs to the CRT1 pathway but not the SML1 pathway. Indeed, deletion of CRT10 enhanced the survival of the mec1 null mutant and increased basal level and DNA damage-induced expression of RNR2 and RNR3, suggesting that Crt10 regulates RNR genes at the transcriptional level. Furthermore, the dun1 mutation is epistatic to crt10 with respect to both HU sensitivity and RNR gene expression. Interestingly, the expression of CRT10 itself is induced by DNA damaging agents and this induction requires DUN1, suggesting that CRT10 plays a role in cellular response to DNA damage and replication blocks. The CRT10 function appears to be achieved by positive regulation of the CRT1 transcript level, indicating that CRT10 is a component of the regulatory circuit.
authors.affiliation: Department of Microbiology and Immunology, University of Saskatchewan, 107 Wiggins Road, Saskatoon, SK S7N 5E5, Canada.
authors.forename: Yu
authors.initials: Y
authors.lastname: Fu
authors.forename: Wei
authors.initials: W
authors.lastname: Xiao
mesh_terms: D001483:Base Sequence; D018797:Cell Cycle Proteins / Q000378:metabolism; D004249:DNA Damage; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D017353:Gene Deletion; D015971:Gene Expression Regulation, Enzymologic; D015966:Gene Expression Regulation, Fungal; D006918:Hydroxyurea / Q000633:toxicity; D047908:Intracellular Signaling Peptides and Proteins; D008969:Molecular Sequence Data; D011494:Protein Kinases / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases; D012333:RNA, Messenger / Q000378:metabolism; D012097:Repressor Proteins; D012264:Ribonucleotide Reductases / Q000235:genetics* / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D014157:Transcription Factors
chemical_list: C509676:CRT10 protein, S cerevisiae; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D047908:Intracellular Signaling Peptides and Proteins; C114542:RFX1 protein, S cerevisiae; D012333:RNA, Messenger; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D012264:Ribonucleotide Reductases; D011494:Protein Kinases; C104169:DUN1 protein, S cerevisiae; C088937:MEC1 protein, S cerevisiae; D017346:Protein Serine-Threonine Kinases; D006918:Hydroxyurea