The molecular mechanism of mitotic inhibition of TFIIH is mediated by phosphorylation of CDK7.
TFIIH is a multisubunit complex, containing ATPase, helicases, and kinase activities. Functionally, TFIIH has been implicated in transcription by RNA polymerase II (RNAPII) and in nucleotide excision repair. A member of the cyclin-dependent kinase family, CDK7, is the kinase subunit of TFIIH. Genetically, CDK7 homologues have been implicated in transcription in Saccharomyces cerevisiae, and in mitotic regulation in Schizosaccharomyces pombe. Here we show that in mitosis the CDK7 subunit of TFIIH and the largest subunit of RNAPII become hyperphosphorylated. MPF-induced phosphorylation of CDK7 results in inhibition of the TFIIH-associated kinase and transcription activities. Negative and positive regulation of TFIIH requires phosphorylation within the T-loop of CDK7. Our data establishes TFIIH and its subunit CDK7 as a direct link between the regulation of transcription and the cell cycle.
Akoulitchev
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S
Howard Hughes Medical Institute, Division of Nucleic Acids Enzymology, Department of Biochemistry, University of Medicine and Dentistry of New Jersey, Piscataway, New Jersey 08854-5635 USA.
Reinberg
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D
D000595:Amino Acid Sequence; D002453:Cell Cycle / Q000235:genetics; D018844:Cyclin-Dependent Kinases; D005434:Flow Cytometry; D006367:HeLa Cells; D006801:Humans; D046911:Macromolecular Substances; D008938:Mitosis / Q000235:genetics*; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D010766:Phosphorylation; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins; D017421:Sequence Analysis; D035381:TATA-Binding Protein Associated Factors; D035362:Transcription Factor TFIID; D051758:Transcription Factor TFIIH; D014157:Transcription Factors / Q000037:antagonists & inhibitors / Q000235:genetics*; D019473:Transcription Factors, TFII; D014158:Transcription, Genetic / Q000235:genetics; D000095043:Cyclin-Dependent Kinase-Activating Kinase
D046911:Macromolecular Substances; D029701:Saccharomyces cerevisiae Proteins; C490039:TAF6 protein, S cerevisiae; D035381:TATA-Binding Protein Associated Factors; D035362:Transcription Factor TFIID; D014157:Transcription Factors; D019473:Transcription Factors, TFII; D051758:Transcription Factor TFIIH; D011494:Protein Kinases; C060137:carboxy-terminal domain kinase; D017346:Protein Serine-Threonine Kinases; D018844:Cyclin-Dependent Kinases; D000095043:Cyclin-Dependent Kinase-Activating Kinase; C000722416:CDK7 protein, human