The global transcriptional regulators, SSN6 and TUP1, play distinct roles in the establishment of a repressive chromatin structure.
Repression of a-cell specific gene expression in yeast alpha cells requires MAT alpha 2 and MCM1, as well as two global repressors, SSN6 and TUP1. Previous studies demonstrated that nucleosomes positioned adjacent to the alpha 2/MCM1 operator in alpha cells directly contribute to repression. To investigate the possibility that SSN6 and TUP1 provide a link between MAT alpha 2/MCM1 and neighboring histones, nucleosome locations were examined in ssn6 and tup1 alpha cells. In both cases, nucleosome positions downstream of the operator were disrupted, and the severity of the disruption correlated with the degree of derepression. Nevertheless, the observed changes in chromatin structure were not dependent on transcription. Our data strongly indicate that SSN6 and TUP1 directly organize repressive regions of chromatin.
Cooper
J P
JP
Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892.
Roth
S Y
SY
Simpson
R T
RT
D018528:ATP-Binding Cassette Transporters / Q000235:genetics; D004270:DNA, Circular / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics; D005656:Fungal Proteins / Q000235:genetics*; D015966:Gene Expression Regulation, Fungal; D006023:Glycoproteins; D000072235:Mating Factor; D026341:Minichromosome Maintenance 1 Protein; D008957:Models, Genetic; D009687:Nuclear Proteins; D009690:Nucleic Acid Conformation; D009707:Nucleosomes / Q000378:metabolism*; D009875:Operator Regions, Genetic / Q000235:genetics; D010455:Peptides / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D012097:Repressor Proteins / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins; D017384:Sequence Deletion; D014157:Transcription Factors / Q000235:genetics; D014158:Transcription, Genetic
D018528:ATP-Binding Cassette Transporters; C065455:CYC8 protein, S cerevisiae; D004270:DNA, Circular; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D006023:Glycoproteins; D026341:Minichromosome Maintenance 1 Protein; D009687:Nuclear Proteins; D009707:Nucleosomes; D010455:Peptides; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; C489277:STE6 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C066502:TUP1 protein, S cerevisiae; D014157:Transcription Factors; D000072235:Mating Factor