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Rho and NusG suppress pervasive antisense transcription in Escherichia coli [tiling array].

ABSTRACT: Despite the prevalence of antisense transcripts in bacterial transcriptomes, little is known about how their synthesis is controlled. We report that a major function of the Escherichia coli termination factor Rho and its co-factor NusG is suppression of ubiquitous antisense transcription genome-wide. Rho binds C-rich unstructured nascent RNA (high C/G ratio) prior to its ATP-dependent dissociation of transcription complexes. NusG is required for efficient termination at minority subsets (~20%) of both antisense and sense Rho-dependent terminators with lower C/G ratio sequences. In contrast, a widely studied nusA deletion proposed to compromise Rho-dependent termination had no effect on antisense or sense Rho-dependent terminators in vivo. Global co-localization of the nucleoid-associated protein H-NS with Rho-dependent terminators and genetic interactions between hns and rho suggest that H-NS aids Rho in suppression of antisense transcription. The combined actions of Rho, NusG, and H-NS appear to be analogous to the Sen1-Nrd1-Nab3 and nucleosome systems that suppress antisense transcription in eukaryotes. Tiling expression microarray experiments were performed in cells treated with 20 ug/ml bicyclomycin or cells deleted for nusG, or a partial deletion of nusA. Labeled cDNAs were hybridized to an E. coli K-12 MG1655 tiling array with overlapping probes at ~12bp spacing across the entire genome. The series contains 14 datasets.

ORGANISM(S): Escherichia coli K-12

SUBMITTER: Jason Peters

PROVIDER: E-GEOD-41938 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Rho and NusG suppress pervasive antisense transcription in Escherichia coli [RNA-seq].

Project description:Despite the prevalence of antisense transcripts in bacterial transcriptomes, little is known about how their synthesis is controlled. We report that a major function of the Escherichia coli termination factor Rho and its co-factor NusG is suppression of ubiquitous antisense transcription genome-wide. Rho binds C-rich unstructured nascent RNA (high C/G ratio) prior to its ATP-dependent dissociation of transcription complexes. NusG is required for efficient termination at minority subsets (~20%) of both antisense and sense Rho-dependent terminators with lower C/G ratio sequences. In contrast, a widely studied nusA deletion proposed to compromise Rho-dependent termination had no effect on antisense or sense Rho-dependent terminators in vivo. Global co-localization of the nucleoid-associated protein H-NS with Rho-dependent terminators and genetic interactions between hns and rho suggest that H-NS aids Rho in suppression of antisense transcription. The combined actions of Rho, NusG, and H-NS appear to be analogous to the Sen1-Nrd1-Nab3 and nucleosome systems that suppress antisense transcription in eukaryotes. RNA-seq experiments were performed on ribosome-depleted RNA from cells treated with 20 ug/ml bicyclomycin or untreated cells. The series contains 4 datasets.

2012-11-01 | E-GEOD-41939 | biostudies-arrayexpress

Rho and NusG suppress pervasive antisense transcription in Escherichia coli [ChIP-chip].

Project description:Despite the prevalence of antisense transcripts in bacterial transcriptomes, little is known about how their synthesis is controlled. We report that a major function of the Escherichia coli termination factor Rho and its co-factor NusG is suppression of ubiquitous antisense transcription genome-wide. Rho binds C-rich unstructured nascent RNA (high C/G ratio) prior to its ATP-dependent dissociation of transcription complexes. NusG is required for efficient termination at minority subsets (~20%) of both antisense and sense Rho-dependent terminators with lower C/G ratio sequences. In contrast, a widely studied nusA deletion proposed to compromise Rho-dependent termination had no effect on antisense or sense Rho-dependent terminators in vivo. Global co-localization of the nucleoid-associated protein H-NS with Rho-dependent terminators and genetic interactions between hns and rho suggest that H-NS aids Rho in suppression of antisense transcription. The combined actions of Rho, NusG, and H-NS appear to be analogous to the Sen1-Nrd1-Nab3 and nucleosome systems that suppress antisense transcription in eukaryotes. Chromatin immunoprecipitation (ChIP) experiments were performed using antibodies against RNA polymerase (RNAP; Beta subunit) in wild-type cells or cells deleted for hns, nusG, or a partial deletion of nusA. Differentially labeled ChIP DNA and genomic DNA were competitively hybridized to an E. coli K-12 MG1655 tiling array with overlapping probes at ~12bp spacing across the entire genome. The series contains 12 datasets.

2012-11-01 | E-GEOD-41936 | biostudies-arrayexpress

Rho and NusG suppress pervasive antisense transcription in Escherichia coli [RNA-seq].

2012-11-01 | GSE41939 | GEO

Rho and NusG suppress pervasive antisense transcription in Escherichia coli [tiling array].

2012-11-01 | GSE41938 | GEO

Rho and NusG suppress pervasive antisense transcription in Escherichia coli [ChIP-chip].

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Genome-wide analysis of transcriptional termination in E. coli

2008-05-16 | GSE10345 | GEO

Transcription profiling of E. coli inhibited for Rho activity to assess Rho function

Project description:Transcription termination factor Rho is essential in enterobacteria. We inhibited Rho activity with bicyclomycin and used microarray experiments to assess Rho function on a genome-wide scale. Rho is a global regulator of gene expression that matches E. coli transcription to translational needs. Remarkably, genes that are most repressed by Rho are prophages and other horizontally-acquired portions of the genome. Elimination of these foreign DNA elements increases resistance to bicyclomycin. Although rho remains essential, such reduced-genome bacteria no longer require Rho cofactors NusA and NusG. Thus, Rho termination, supported by NusA and NusG, is required to suppress the toxic activity of foreign DNA. Global regulation of transcription termination by Rho, NusA, and NusG. Experiment Overall Design: Two sets of experiments are presented. First, treatment of E. coli with Rho inhibitor bicyclomycin was performed in strains MG1655 and O157:H7 EDL933 for twenty minutes at concentrations of 10, 25, or 100 micrograms/milliliter. In the second set of experiments the reduced-genome strain MDS42 was treated with bicyclomycin as well as having deletions of the genes nusA and nusG. Total RNA was extracted and hybridized to the Affymetrix E. coli Genome 2.0 array, which contains complete genome coverage of four strains of E. coli.

2008-06-20 | E-GEOD-10345 | biostudies-arrayexpress

NusA-dependent Transcription Termination Prevents Global Misregulation of Gene Expression

Project description:Canonical bacterial intrinsic terminators do not require additional factors for efficient transcription termination, although the general transcription elongation factor NusA was known to increase the termination efficiency slightly in vitro. We found that the effect of NusA varies widely among different terminators and identified a subclass of weak non-canonical terminators that largely depend on NusA for recognition by RNA polymerase. Using genome-wide 3â end-mapping on an engineered Bacillus subtilis NusA depletion strain, we identified >2000 intrinsic terminators, hundreds of which are NusA-dependent. Our in vitro and in vivo characterization showed that terminators with weak RNA hairpins and distal U-tract interruptions tend to be NusA-dependent. Our observations indicate that the lethality associated with deletion of nusA is caused by global readthrough of NusA-dependent terminators, resulting in misregulation of physiologically important downstream genes. We also show that nusA expression is autoregulated by a transcription attenuation mechanism that is mediated by NusA-dependent termination. 3' end-mapping and mRNA profiling of stationary phase B. subtilis NusA-depletion (PLBS802) strain in NusA expressing and depleted conditions, 6 replicates each.

2016-07-03 | E-GEOD-67058 | biostudies-arrayexpress

NusA-dependent Transcription Termination Prevents Global Misregulation of Gene Expression

Project description:Canonical bacterial intrinsic terminators do not require additional factors for efficient transcription termination, although the general transcription elongation factor NusA was known to increase the termination efficiency slightly in vitro. We found that the effect of NusA varies widely among different terminators and identified a subclass of weak non-canonical terminators that largely depend on NusA for recognition by RNA polymerase. Using genome-wide 3’ end-mapping on an engineered Bacillus subtilis NusA depletion strain, we identified >2000 intrinsic terminators, hundreds of which are NusA-dependent. Our in vitro and in vivo characterization showed that terminators with weak RNA hairpins and distal U-tract interruptions tend to be NusA-dependent. Our observations indicate that the lethality associated with deletion of nusA is caused by global readthrough of NusA-dependent terminators, resulting in misregulation of physiologically important downstream genes. We also show that nusA expression is autoregulated by a transcription attenuation mechanism that is mediated by NusA-dependent termination.

2016-01-01 | GSE67058 | GEO

Regulator trafficking on bacterial transcription units in vivo

Project description:The in vivo trafficking patterns on DNA by the bacterial regulators of transcript elongation Sigma70, Rho, NusA, and NusG and the explanation for high promoter-proximal levels or peaks of RNA polymerase (RNAP) are unknown. Genome-wide ChIP-chip on E. coli revealed distinct association patterns of regulators as RNAP transcribes away from promoters (Rho first, then NusA, and then NusG). However, the interactions of elongating complexes with these regulators, including a weak interaction with Sigma70, did not differ significantly among most transcription units. A modest variation of NusG signal among genes reflected increased NusG interaction as transcription progresses, rather than functional specialization of elongating complexes. Promoter-proximal RNAP peaks were offset from Sigma70 peaks in the direction of transcription and co-occurred with NusA and Rho peaks, suggesting that the RNAP peaks reflected elongating, rather than initiating, complexes. However, inhibition of Rho did not increase RNAP levels within genes downstream of the RNAP peaks, suggesting the peaks are caused by a mechanism other than simple Rho-dependent attenuation. Chromatin immunoprecipitation (ChIP) experiments were performed using antibodies against RNA polymerase (Beta' subunit), Sigma70, NusA, NusG, or Rho. Differentially labeled ChIP DNA and genomic DNA were competitively hybridized to an E. coli K-12 MG1655 tiling array with overlapping probes at ~24bp spacing across the entire genome. The series contains 17 total datasets.

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