Requirement for TFIIH kinase activity in transcription by RNA polymerase II

Abstract

AN array of tandem heptapeptide repeats at the carboxv -terminal domain (CTD) of the largest subunit of RNA polymerase II constitute a highly conserved structure essential for viability1-3. Studies have established that the CTD is phosphorylated at different stages of the transcription cycle4-7, and that it may be involved in transcriptional regulation8-12. The exact role of the CTD remains elusive, as in vitro reconstituted transcription using the adenovirus major late promoter does not require the CTD13, 14. Previous studies7, 15, 16 showed that transcription from the murine dihydro-folate reductase (DHFR) promoter can be only accomplished by the form of RNA polymerase II that contains the hypophosphoryl-ated CTD (RNAPIIA), but not by the form that lacks it (RNAPIIB)7. Here we show that the CTD, but not its phosphoryla-tion, is required for initiation of transcription. We also show that transcription requires CTD kinase activity provided by the CDK7 subunit of TFIIH17-19. © 1995 Nature Publishing Group.