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 language | English (US) |
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Article number | e04970 |
Journal | eLife |
Volume | 2015 |
Issue number | 4 |
DOIs | |
State | Published - Jan 16 2015 |
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)