Abstract
Transcription activation in yeast (Saccharomyces cerevisiae) involves ordered recruitment of transcription factor complexes, such as TFIID, SAGA, and Mot1p. Previously, we showed that both Mot1p and Taf1p are recruited to the HXT2 and HXT4 genes, which encode hexose transporter proteins. Here, we show that SAGA also binds to the HXT2 and HXT4 promoters and plays a pivotal role in the recruitment of Mot1p and Taf1p. The deletion of either SPT3 or SPT8 reduces Mot1p binding to HXT2 and HXT4. Surprisingly, the deletion of GCN5 reduces Taf1p binding to both promoters. When GCN5 is deleted in spt3Delta or spt8Delta strains, neither Mot1p nor Taf1p binds, and this results in a diminished recruitment of TATA binding protein and polymerase II to the HXT4 but not the HXT2 promoter. This is reflected by the SAGA-dependent expression of HXT4. In contrast, SAGA-independent induction of HXT2 suggests a functional redundancy with other factors. A functional interplay of different SAGA subunits with Mot1p and Taf1p was supported by phenotypic analysis of MOT1 SAGA or TAF1/SAGA double mutant strains, which revealed novel genetic interactions between MOT1 and SPT8 and between TAF1 and GCN5. In conclusion, our data demonstrate functional links between SAGA, Mot1p, and TFIID in HXT gene regulation.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Adenosine Triphosphatases
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DNA Helicases / genetics
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DNA Helicases / metabolism*
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DNA-Binding Proteins / genetics
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DNA-Binding Proteins / metabolism
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Gene Expression Regulation, Fungal*
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Glucose / metabolism
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Glucose Transport Proteins, Facilitative
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Histone Acetyltransferases
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Membrane Proteins / genetics
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Membrane Proteins / metabolism
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Monosaccharide Transport Proteins / genetics
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Monosaccharide Transport Proteins / metabolism
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Promoter Regions, Genetic
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Protein Binding
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Protein Kinases / genetics
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Protein Kinases / metabolism
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Protein Subunits / genetics
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Protein Subunits / metabolism*
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Saccharomyces cerevisiae / genetics
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Saccharomyces cerevisiae / metabolism
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Saccharomyces cerevisiae Proteins / genetics
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Saccharomyces cerevisiae Proteins / metabolism*
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TATA-Binding Protein Associated Factors / genetics
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TATA-Binding Protein Associated Factors / metabolism*
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Transcription Factor TFIID / genetics
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Transcription Factor TFIID / metabolism*
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Transcription Factors / genetics
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Transcription Factors / metabolism*
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Transcription, Genetic
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Transcriptional Activation
Substances
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DNA-Binding Proteins
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Glucose Transport Proteins, Facilitative
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HXT2 protein, S cerevisiae
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HXT4 protein, S cerevisiae
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Membrane Proteins
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Monosaccharide Transport Proteins
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Protein Subunits
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SPT3 protein, S cerevisiae
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SPT8 protein, S cerevisiae
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Saccharomyces cerevisiae Proteins
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TAF1 protein, S cerevisiae
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TATA-Binding Protein Associated Factors
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Transcription Factor TFIID
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Transcription Factors
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GCN5 protein, S cerevisiae
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Histone Acetyltransferases
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Protein Kinases
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Adenosine Triphosphatases
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MOT1 protein, S cerevisiae
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DNA Helicases
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Glucose