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

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. In this study, 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.

SUBMITTER: Kotlajich MV

PROVIDER: S-EPMC4337669 | biostudies-literature | 2015 Jan

REPOSITORIES: biostudies-literature

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

Kotlajich Matthew V MV Hron Daniel R DR Boudreau Beth A BA Sun Zhiqiang Z Lyubchenko Yuri L YL Landick Robert R

eLife 20150116

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. In this study, 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 termi ...[more]

PMID: 25594903

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

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

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