TFIIH Action in Transcription Initiation and Promoter Escape Requires Distinct Regions of Downstream Promoter DNA

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 98; no. 10; pp. 5544 - 5549
• Main Authors: Spangler, Lori, Wang, Xiaoxue, Conaway, Joan W., Conaway, Ronald C., Dvir, Arik
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences 08.05.2001; National Acad Sciences; The National Academy of Sciences
• Subjects: Base Sequence; Biochemistry; Biological Sciences; CDK7 gene; Deoxyribonucleic acid; DNA; DNA - genetics; Enzymes; Genes; Medical research; Molecular Sequence Data; Nucleotides; Peptide initiation factors; Promoter regions; Promoter Regions, Genetic; Research universities; Ribonucleic acid; RNA; RNA Polymerase II - metabolism; TFIIH protein; Transcription Factor TFIIH; Transcription Factors - physiology; Transcription Factors, TFII; Transcription, Genetic - physiology; XPB gene; XPD gene; Yeasts
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.101004498

TFIIH is a multifunctional RNA polymerase II general initiation factor that includes two DNA helicases encoded by the Xeroderma pigmentosum complementation group B (XPB) and D (XPD) genes and a cyclin-dependent protein kinase encoded by the CDK7 gene. Previous studies have shown that the TFIIH XPB DNA helicase plays critical roles not only in transcription initiation, where it catalyzes ATP-dependent formation of the open complex, but also in efficient promoter escape, where it suppresses arrest of very early RNA polymerase II elongation intermediates. In this report, we present evidence that ATP-dependent TFIIH action in transcription initiation and promoter escape requires distinct regions of the DNA template; these regions are well separated from the promoter region unwound by the XPB DNA helicase and extend, respectively, ≈23-39 and ≈39-50 bp downstream from the transcriptional start site. Taken together, our findings bring to light a role for promoter DNA in TFIIH action and are consistent with the model that TFIIH translocates along promoter DNA ahead of the RNA polymerase II elongation complex until polymerase has escaped the promoter.