The Initiation Factor TFE and the Elongation Factor Spt4/5 Compete for the RNAP Clamp during Transcription Initiation and Elongation

• DOI: 10.1016/j.molcel.2011.05.030
• Publication Date: 2011-07-25T05:14:32Z
• Authors: Dina Grohmann; Julia Nagy; Anirban Chakraborty; Daniel Klose; Daniel Fielden; Richard H. Ebright; Jens Michaelis; Finn Werner
• Keywords: Models, Molecular; 0303 health sciences; Binding Sites; Base Sequence; Transcription, Genetic; Chromosomal Proteins, Non-Histone; Protein Conformation; Archaeal Proteins; Molecular Sequence Data; Cell Biology; DNA-Directed RNA Polymerases; Archaea; Article; 03 medical and health sciences; Fluorescence Resonance Energy Transfer; Sulfolobus solfataricus; Amino Acid Sequence; Transcriptional Elongation Factors; Molecular Biology

TFIIE and the archaeal homolog TFE enhance DNA strand separation of eukaryotic RNAPII and the archaeal RNAP during transcription initiation by an unknown mechanism. We have developed a fluorescently labeled recombinant M. jannaschii RNAP system to probe the archaeal transcription initiation complex, consisting of promoter DNA, TBP, TFB, TFE, and RNAP. We have localized the position of the TFE winged helix (WH) and Zinc ribbon (ZR) domains on the RNAP using single-molecule FRET. The interaction sites of the TFE WH domain and the transcription elongation factor Spt4/5 overlap, and both factors compete for RNAP binding. Binding of Spt4/5 to RNAP represses promoter-directed transcription in the absence of TFE, which alleviates this effect by displacing Spt4/5 from RNAP. During elongation, Spt4/5 can displace TFE from the RNAP elongation complex and stimulate processivity. Our results identify the RNAP "clamp" region as a regulatory hot spot for both transcription initiation and transcription elongation.