Regulation of transcription elongation by Spt4/5 and NusA. (360G-Wellcome-079351_Z_06_Z)

Gene expression is regulated during the three principal stages of the transcription cycle: initiation, elongation and termination. General transcription factors interact with RNA polymerase (RNAP, the enzyme that catalyses RNA synthesis) during these stages and modulate its catalytic properties. Whereas the process of transcription initiation is reasonably well understood, not much is known about the mechanisms of transcription elongation. The archaeal RNAP is homologous to eukaryotic RNAPII in terms of its subunit composition and overall architecture, and quite distinct from the bacterial enzyme. However, both bacterial- (NusA) and eukaryote-like (Spt4/5) factors govern transcription elongation of the archaeal RNAP. I have recently developed protocols for the in vitro reconstitution of the archaeal transcription machinery, including its 12-subunit RNAP, from purely recombinant components. My laboratory now wants to apply this system to investigate the molecular mechanisms of transcription elongation. Using both biochemical and molecular biological tools we want to (1) resolve the interaction network between the three elongation factors, the twelve RNAP subunits and the nucleic acid scaffold (DNA/RNA) of the elongation complex and (2) characterise the molecular mechanisms by which these interactions regulate the nucleic acid binding and catalytic properties of RNAP during transcription elongation.