Cdk7 is required for full activation of Drosophila heat shock genes and RNA polymerase II phosphorylation in vivo.
TFIIH has been implicated in several fundamental cellular processes, including DNA repair, cell cycle progression, and transcription. In transcription, the helicase activity of TFIIH functions to melt promoter DNA; however, the in vivo function of the Cdk7 kinase subunit of TFIIH, which has been hypothesized to be involved in RNA polymerase II (Pol II) phosphorylation, is not clearly understood. Using temperature-sensitive and null alleles of cdk7, we have examined the role of Cdk7 in the activation of Drosophila heat shock genes. Several in vivo approaches, including polytene chromosome immunofluorescence, nuclear run-on assays, and, in particular, a protein-DNA cross-linking assay customized for adults, revealed that Cdk7 kinase activity is required for full activation of heat shock genes, promoter-proximal Pol II pausing, and Pol II-dependent chromatin decondensation. The requirement for Cdk7 occurs very early in the transcription cycle. Furthermore, we provide evidence that TFIIH associates with the elongation complex much longer than previously suspected.
Schwartz
Brian E
BE
Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York, USA.
Larochelle
Stephane
S
Suter
Beat
B
Lis
John T
JT
D000818:Animals; D030801:Animals, Genetically Modified; D002843:Chromatin / Q000378:metabolism; D018844:Cyclin-Dependent Kinases / Q000235:genetics / Q000378:metabolism*; D004330:Drosophila / Q000235:genetics*; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004789:Enzyme Activation; D015971:Gene Expression Regulation, Enzymologic; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D018869:Heat-Shock Response / Q000235:genetics*; D010766:Phosphorylation; D017354:Point Mutation; D011401:Promoter Regions, Genetic; D021122:Protein Subunits / Q000235:genetics; D012319:RNA Polymerase II / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D011994:Recombinant Proteins / Q000302:isolation & purification / Q000378:metabolism; D013696:Temperature; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic; D000095043:Cyclin-Dependent Kinase-Activating Kinase
D002843:Chromatin; D029721:Drosophila Proteins; D006360:Heat-Shock Proteins; D021122:Protein Subunits; D012333:RNA, Messenger; D011994:Recombinant Proteins; D014157:Transcription Factors; D018844:Cyclin-Dependent Kinases; D012319:RNA Polymerase II; D000095043:Cyclin-Dependent Kinase-Activating Kinase