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Article

  • The EMBO Journal (2006) 25, 3784 - 3790
  • doi:10.1038/sj.emboj.7601261

Published online: 3 August 2006

RNA polymerase and an activator form discrete subcomplexes in a transcription initiation complex

Sebastian Maurer1, Jürgen Fritz1, Georgi Muskhelishvili1 and Andrew Travers2

  1. International University Bremen, Bremen, Germany
  2. MRC Laboratory of Molecular Biology, Cambridge, UK

Correspondence to:

Andrew Travers, MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 2QH, UK. Tel.: +44 1223 402419; Fax: +44 1223 412142; E-mail: aat@mrc-lmb.cam.ac.uk

Received 23 March 2006; Accepted 6 July 2006

Using high-resolution atomic force microscopy (AFM) we show that in a ternary complex of an activator protein, FIS, and RNA polymerase containing the sigma70 specificity factor at the Escherichia coli tyrT promoter the polymerase and the activator form discrete, but connected, subcomplexes in close proximity. This is the first time that a ternary complex between an activator, a sigma70 polymerase holoenzyme and promoter DNA has been visualised. Individually FIS and RNA polymerase wrap approx80 and 150 bp of promoter DNA, respectively. We suggest that the architecture of the ternary complex provides a general paradigm for the facilitation of direct, but weak, interactions between polymerase and an activator.

  • Keywords:

    • activator–polymerase complex,
    • DNA wrapping,
    • FIS,
    • RNA polymerase,
    • torsional transmission