Bridged filaments of histone-like nucleoid structuring protein pause RNA polymerase and aid termination in bacteria

Matthew V. Kotlajich, Daniel R. Hron, Beth A. Boudreau, Zhiqiang Sun, Yuri L. Lyubchenko, Robert Landick

Research output: Contribution to journalArticle

55 Scopus citations

Abstract

Bacterial H-NS forms nucleoprotein filaments that spread on DNA and bridge distant DNA sites. H-NS filaments co-localize with sites of Rho-dependent termination in Escherichia coli, but their direct effects on transcriptional pausing and termination are untested. Here we report that bridged H-NS filaments strongly increase pausing by E. coli RNA polymerase at a subset of pause sites with high potential for backtracking. Bridged but not linear H-NS filaments promoted Rho dependent termination by increasing pause dwell times and the kinetic window for Rho action. By observing single H-NS filaments and elongating RNA polymerase molecules using atomic force microscopy, we established that bridged filaments surround paused complexes. Our results favor a model in which H-NS-constrained changes in DNA supercoiling driven by transcription promote pausing at backtracking-susceptible sites. Our findings provide a mechanistic rationale for H-NS stimulation of Rho-dependent termination in horizontally transferred genes and during pervasive antisense and noncoding transcription in bacteria.

Original languageEnglish (US)
JournaleLife
Volume2015
Issue number4
DOIs
StatePublished - Jan 16 2015

    Fingerprint

Keywords

  • GreB
  • H-NS
  • NusG
  • Pausing
  • RNAP
  • RfaH
  • Rho
  • Termination
  • Transcription

ASJC Scopus subject areas

  • Neuroscience(all)
  • Immunology and Microbiology(all)
  • Biochemistry, Genetics and Molecular Biology(all)

Cite this