Identification of genes required for alpha 2 repression in Saccharomyces cerevisiae.
Transcriptional repression of the a-specific genes in Saccharomyces cerevisiae alpha cells involves the concerted action of several proteins. The homeodomian protein alpha 2, together with MCM1, recruits two general transcriptional repressors, SSN6 and TUP1, to the promoters of a-specific genes. SSN6 and TUP1 then mediate repression of the a-specific genes. SIN4, another general negative regulator, is required for this repression, but unlike tup1 or ssn6 deletions, sin4 deletions cause only partial loss of repression. We have screened for other genes required for a-specific gene repression in alpha cells. In addition to recovering multiple alleles of previously identified genes required for this process (referred to as alpha 2 repression), we have identified four other genes, designated ARE1, ARE2, ARE3, and ARE4 (for alpha 2 repression). Recessive mutations in the ARE genes cause partial loss of a-specific gene repression and cause pleiotropic phenotypes similar to those resulting from mutations in SSN6, TUP1, or SIN4, suggesting that the ARE genes are general negative regulators. Based on our initial analysis, we propose that two distinct classes of general negative regulators cooperate to bring about full levels of alpha 2 repression. The sequence of ARE1 revealed that it encodes a CDC28-related protein kinase, identical to UME5, and thus suggests that protein phosphorylation plays a role in alpha 2 repression.
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Department of Microbiology, University of California, San Francisco 94143-0502, USA.
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D004268:DNA-Binding Proteins / Q000502:physiology; D005656:Fungal Proteins / Q000235:genetics* / Q000502:physiology; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D017930:Genes, Reporter; D005816:Genetic Complementation Test; D008040:Genetic Linkage; D018398:Homeodomain Proteins; D056892:Mediator Complex; D026341:Minichromosome Maintenance 1 Protein; D008957:Models, Genetic; D016254:Mutagenesis, Insertional; D009687:Nuclear Proteins; D016133:Polymerase Chain Reaction; D011494:Protein Kinases / Q000235:genetics* / Q000502:physiology; D012319:RNA Polymerase II / Q000235:genetics* / Q000502:physiology; D012097:Repressor Proteins / Q000235:genetics* / Q000502:physiology; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins; D015534:Trans-Activators; D014157:Transcription Factors / Q000502:physiology; D014158:Transcription, Genetic
C065455:CYC8 protein, S cerevisiae; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D018398:Homeodomain Proteins; C062928:MATA2 protein, S cerevisiae; D056892:Mediator Complex; D026341:Minichromosome Maintenance 1 Protein; D009687:Nuclear Proteins; D012097:Repressor Proteins; C076878:SIN4 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C066502:TUP1 protein, S cerevisiae; D015534:Trans-Activators; D014157:Transcription Factors; D011494:Protein Kinases; D012319:RNA Polymerase II