The NOT, SPT3, and MOT1 genes functionally interact to regulate transcription at core promoters.
Previous studies demonstrated that mutations in the Saccharomyces cerevisiae NOT genes increase transcription from TATA-less promoters. In this report, I show that in contrast, mutations in the yeast MOT1 gene decrease transcription from TATA-less promoters. I also demonstrate specific genetic interactions between the Not complex, Mot1p, and another global regulator of transcription in S. cerevisiae, Spt3p. Five distinct genetic interactions have been established. First, a null allele of SPT3, or a mutation in SPT15 that disrupts the interaction between Spt3p and TATA-binding protein (TBP), allele specifically suppressed the not1-2 mutation. Second, in contrast to not mutations, mutations in MOT1 decreased HIS3 and HIS4 TATA-less transcription. Third, not mutations suppressed toxicity due to overexpression of TBP in mot1-1 mutants. Finally, overexpression of SPT3 caused a weak Not- mutant phenotype in mot1-1 mutants. Collectively, these results suggest a novel type of transcriptional regulation whereby the distribution of limiting TBP (TFIID) on weak and strong TBP-binding core promoters is regulated: Mot1p releases stably bound TBP to allow its redistribution to low-affinity sites, and the Not proteins negatively regulate the activity of factors such as Spt3p that favor distribution of TBP to these low-affinity sites.
Collart
M A
MA
Department of Medical Biochemistry, University of Geneva Medical School, Switzerland.
D000251:Adenosine Triphosphatases; D004265:DNA Helicases / Q000235:genetics*; D004268:DNA-Binding Proteins; D005656:Fungal Proteins / Q000235:genetics*; D015966:Gene Expression Regulation, Fungal; D017874:Immediate-Early Proteins / Q000235:genetics*; D009154:Mutation; D057126:Nuclear Receptor Subfamily 4, Group A, Member 2; D011401:Promoter Regions, Genetic / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins; D035381:TATA-Binding Protein Associated Factors; D014157:Transcription Factors / Q000235:genetics*
D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D017874:Immediate-Early Proteins; D057126:Nuclear Receptor Subfamily 4, Group A, Member 2; C075582:SPT3 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D035381:TATA-Binding Protein Associated Factors; D014157:Transcription Factors; D000251:Adenosine Triphosphatases; C073676:MOT1 protein, S cerevisiae; D004265:DNA Helicases