Abstract
Mot1 is an essential, conserved, TATA-binding protein (TBP)-associated factor in Saccharomyces cerevisiae with well-established roles in the global control of RNA polymerase II (Pol II) transcription. Previous results have suggested that Mot1 functions exclusively in Pol II transcription, but here we report a novel role for Mot1 in regulating transcription by RNA polymerase I (Pol I). In vivo, Mot1 is associated with the ribosomal DNA, and loss of Mot1 results in decreased rRNA synthesis. Consistent with a direct role for Mot1 in Pol I transcription, Mot1 also associates with the Pol I promoter in vitro in a reaction that depends on components of the Pol I general transcription machinery. Remarkably, in addition to Mot1's role in initiation, rRNA processing is delayed in mot1 cells. Taken together, these results support a model in which Mot1 affects the rate and efficiency of rRNA synthesis by both direct and indirect mechanisms, with resulting effects on transcription activation and the coupling of rRNA synthesis to processing.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
MeSH terms
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Adenosine Triphosphatases / metabolism
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Chromatin / metabolism
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DNA Helicases / metabolism*
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DNA, Ribosomal / ultrastructure
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Gene Expression Regulation, Fungal
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Genes, Fungal
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Mutation / genetics
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Promoter Regions, Genetic / genetics
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Protein Transport
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RNA Polymerase I / metabolism
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RNA Processing, Post-Transcriptional / genetics
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RNA, Ribosomal / biosynthesis*
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RNA, Ribosomal / genetics
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RNA, Ribosomal / ultrastructure
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Repetitive Sequences, Nucleic Acid / genetics
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Saccharomyces cerevisiae / cytology
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Saccharomyces cerevisiae / genetics
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Saccharomyces cerevisiae / metabolism*
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Saccharomyces cerevisiae / ultrastructure
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Saccharomyces cerevisiae Proteins / metabolism*
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TATA-Binding Protein Associated Factors / metabolism*
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Transcription Factors / metabolism
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Transcription, Genetic
Substances
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Chromatin
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DNA, Ribosomal
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RNA, Ribosomal
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Saccharomyces cerevisiae Proteins
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TATA-Binding Protein Associated Factors
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Transcription Factors
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RNA Polymerase I
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Adenosine Triphosphatases
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MOT1 protein, S cerevisiae
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DNA Helicases