Mechanisms and regulation of RNA polymerase transcription
The RNA polymerase laboratory at the UCL Institute for Structural and Molecular Biology follows a multidisciplinary research programme that aims at unravelling the molecular mechanisms of transcription. Transcription is a fundamental process in biology and evolutionary ancient and the engines of cellular transcription - RNA polymerases (RNAPs) - are closely related in all three domains of life. This applies particularly to the archaeal and eukaryotic systems, which are not only similar in terms of RNAP subunit composition and architecture, but also regarding the transcription initiation and elongation factors and molecular mechanisms that govern their activity. We have developed a recombinant transcription system from the hyperthermophilic euryarchaeon Methanocaldococcus jannaschii that is reconstituted from individual subunits. This allows us to perturb the RNAP by a molecular genetics and biophysical approaches to assess function, complex topology and -dynamics by the use of molecular probes (e.g. fluorescent dyes) incorporated into RNAP subunits and transcription factors. We have applied this bespoke transcription system to illuminate the structure, function and evolution of transcription in vitro. In order to bridge the gap to the living world we have developed genetic tools to characterise in vivo phenotypes of mutants of the crenarchaeal S. solfataricus RNAP and transcription factors, and adapted systems biology approaches to (i) map the global promoter landscape and transcriptome of M. jannaschii, and to (ii) describe the whole genome occupancy of the transcription apparatus.
