Evidence for the involvement of the Glc7-Reg1 phosphatase and the Snf1-Snf4 kinase in the regulation of INO1 transcription in Saccharomyces cerevisiae.
Binding of the TATA-binding protein (TBP) to the promoter is a pivotal step in RNA polymerase II transcription. To identify factors that regulate TBP, we selected for suppressors of a TBP mutant that exhibits promoter-specific defects in activated transcription in vivo and severely reduced affinity for TATA boxes in vitro. Dominant mutations in SNF4 and recessive mutations in REG1, OPI1, and RTF2 were isolated that specifically suppress the inositol auxotrophy of the TBP mutant strains. OPI1 encodes a repressor of INO1 transcription. REG1 and SNF4 encode regulators of the Glc7 phosphatase and Snf1 kinase, respectively, and have well-studied roles in glucose repression. In two-hybrid assays, one SNF4 mutation enhances the interaction between Snf4 and Snf1. Suppression of the TBP mutant by our reg1 and SNF4 mutations appears unrelated to glucose repression, since these mutations do not alleviate repression of SUC2, and glucose levels have little effect on INO1 transcription. Moreover, mutations in TUP1, SSN6, and GLC7, but not HXK2 and MIG1, can cause suppression. Our data suggest that association of TBP with the TATA box may be regulated, directly or indirectly, by a substrate of Snf1. Analysis of INO1 transcription in various mutant strains suggests that this substrate is distinct from Opi1.
Shirra
M K
MK
Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA.
Arndt
K M
KM
D055372:AMP-Activated Protein Kinases; D015152:Blotting, Northern; D002352:Carrier Proteins; D018797:Cell Cycle Proteins / Q000235:genetics; D002843:Chromatin / Q000378:metabolism; D005656:Fungal Proteins / Q000502:physiology*; D015966:Gene Expression Regulation, Fungal; D015698:Genomic Library; D005838:Genotype; D005990:Glycerol / Q000494:pharmacology; D006026:Glycoside Hydrolases / Q000378:metabolism; D019344:Lactic Acid / Q000494:pharmacology; D016296:Mutagenesis; D007296:Myo-Inositol-1-Phosphate Synthase / Q000235:genetics*; D010749:Phosphoprotein Phosphatases / Q000502:physiology*; D010957:Plasmids; D011494:Protein Kinases / Q000502:physiology*; D054645:Protein Phosphatase 1; D017346:Protein Serine-Threonine Kinases / Q000502:physiology*; D012319:RNA Polymerase II / Q000378:metabolism; D011887:Raffinose / Q000494:pharmacology; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins; D013489:Suppression, Genetic / Q000235:genetics; D035181:TATA-Box Binding Protein / Q000031:analogs & derivatives; D013997:Time Factors; D014157:Transcription Factors / Q000502:physiology*; D014158:Transcription, Genetic; D014404:Tubulin / Q000378:metabolism; D043324:beta-Fructofuranosidase; D001616:beta-Galactosidase / Q000378:metabolism
D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D002843:Chromatin; D005656:Fungal Proteins; C115017:SPT15 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D035181:TATA-Box Binding Protein; D014157:Transcription Factors; D014404:Tubulin; D019344:Lactic Acid; D011494:Protein Kinases; C071570:SNF1-related protein kinases; D017346:Protein Serine-Threonine Kinases; C078651:SNF4 protein, S cerevisiae; D055372:AMP-Activated Protein Kinases; D012319:RNA Polymerase II; D010749:Phosphoprotein Phosphatases; D054645:Protein Phosphatase 1; C070829:REG1 protein, S cerevisiae; D006026:Glycoside Hydrolases; D001616:beta-Galactosidase; D043324:beta-Fructofuranosidase; D007296:Myo-Inositol-1-Phosphate Synthase; D011887:Raffinose; D005990:Glycerol