The bacteriophage lambda Q antiterminator protein contacts the beta-flap domain of RNA polymerase.

  • Deighan P
  • Diez C
  • Leibman M
 et al. 
  • 24

    Readers

    Mendeley users who have this article in their library.
  • N/A

    Citations

    Citations of this article.

Abstract

The multisubunit RNA polymerase (RNAP) in bacteria consists of a catalytically active core enzyme (alpha(2)beta beta'omega) complexed with a sigma factor that is required for promoter-specific transcription initiation. During early elongation the stability of interactions between sigma and core decreases, in part because of the nascent RNA-mediated destabilization of an interaction between region 4 of sigma and the flap domain of the beta-subunit (beta-flap). The nascent RNA-mediated destabilization of the sigma region 4/beta-flap interaction is required for the bacteriophage lambda Q antiterminator protein (lambdaQ) to engage the RNAP holoenzyme. Here, we provide an explanation for this requirement by showing that lambdaQ establishes direct contact with the beta-flap during the engagement process, thus competing with sigma(70) region 4 for access to the beta-flap. We also show that lambdaQ's affinity for the beta-flap is calibrated to ensure that lambdaQ activity is restricted to the lambda late promoter P(R'). Specifically, we find that strengthening the lambdaQ/beta-flap interaction allows lambdaQ to bypass the requirement for specific cis-acting sequence elements, a lambdaQ-DNA binding site and a RNAP pause-inducing element, that normally ensure lambdaQ is recruited exclusively to transcription complexes associated with P(R'). Our findings demonstrate that the beta-flap can serve as a direct target for regulators of elongation.

Get free article suggestions today

Mendeley saves you time finding and organizing research

Sign up here
Already have an account ?Sign in

Authors

  • Padraig Deighan

  • Cristina Montero Diez

  • Mark Leibman

  • Ann Hochschild

  • Bryce E Nickels

Cite this document

Choose a citation style from the tabs below

Save time finding and organizing research with Mendeley

Sign up for free