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σF regulon

ABSTRACT: The Alphaproteobacterium Caulobacter crescentus inhabits low-nutrient environments and can tolerate certain levels of heavy metal in these sites. It has been reported that C. crescentus responds to chromium exposure by altering expression of a large number of genes. In this work, we showed that the ECF sigma factor SigF is one of the regulatory proteins involved in the control of this transcriptional response. Microarray experiments from cells under dichromate stress showed that SigF controls a small regulon consisting of seven genes. Promoter analyses revealed that a conserved SigF-dependent sequence is located upstream of all but one gene of this regulon. Surprisingly, sigF itself was not found to be strongly auto-regulated under dichromate exposure. Furthermore, we showed that the second gene (CC3252) in the sigF operon acts as a negative regulator of SigF function, as overexpression of this putative membrane protein abolishes the transcriptional activation of sigF and its regulon under dichromate stress. Additionally, we found that substitution of one or both the conserved cysteines in the protein encoded by CC3252 (C131 and C181) affects the ability of this protein in maintaining expression of SigF-dependent genes at basal levels. Interestingly, we showed that the activation of SigF is not caused by reactive oxygen species generated as a consequence of dichromate exposure. Therefore, dichromate most probably may lead to conformational changes in the putative anti-sigma factor CC3252, releasing SigF to bind RNA polymerase core and drive transcription of its regulon.

ORGANISM(S): Caulobacter vibrioides CB15 Caulobacter vibrioides NA1000

PROVIDER: GSE32406 | GEO | 2012/10/02

SECONDARY ACCESSION(S): PRJNA146399

REPOSITORIES: GEO

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σF regulon

Project description:The Alphaproteobacterium Caulobacter crescentus inhabits low-nutrient environments and can tolerate certain levels of heavy metal in these sites. It has been reported that C. crescentus responds to chromium exposure by altering expression of a large number of genes. In this work, we showed that the ECF sigma factor SigF is one of the regulatory proteins involved in the control of this transcriptional response. Microarray experiments from cells under dichromate stress showed that SigF controls a small regulon consisting of seven genes. Promoter analyses revealed that a conserved SigF-dependent sequence is located upstream of all but one gene of this regulon. Surprisingly, sigF itself was not found to be strongly auto-regulated under dichromate exposure. Furthermore, we showed that the second gene (CC3252) in the sigF operon acts as a negative regulator of SigF function, as overexpression of this putative membrane protein abolishes the transcriptional activation of sigF and its regulon under dichromate stress. Additionally, we found that substitution of one or both the conserved cysteines in the protein encoded by CC3252 (C131 and C181) affects the ability of this protein in maintaining expression of SigF-dependent genes at basal levels. Interestingly, we showed that the activation of SigF is not caused by reactive oxygen species generated as a consequence of dichromate exposure. Therefore, dichromate most probably may lead to conformational changes in the putative anti-sigma factor CC3252, releasing SigF to bind RNA polymerase core and drive transcription of its regulon. Three replicates perfomed with independent biological samples

2012-10-02 | E-GEOD-32406 | biostudies-arrayexpress

2-Methylcitrate cycle: a well-regulated controller in Bacillus sporulation

Project description:To understand which gene(s) are affected by 2-methylcitrate to lead to the delayed sporulation in ∆prpD, we extracted the total RNA from BMB171 and ∆prpD at 12 h for whole genome transcription analysis by RNA sequencing (RNA-Seq). Our RNA-seq data showed that transcriptions of almost all of the SigF regulon genes, as concluded from the B. subtilis regulon, were significantly down-regulated in ∆prpD compared with the wild type BMB171. However, almost all the regulon genes of SigH, a sigma factor that functions upstream of SigF, were significantly up-regulated in ∆prpD. Those genes included spo0A, the early-expressed operon spoIIA and sigF itself. These results indicated that dysregulation of genes occurred on various levels. In particular, though, post-transcriptional inhibition of sigF functionality might subsequently lead to down-regulation of SigF regulon genes in the ∆prpD mutant.

2019-11-14 | GSE140317 | GEO

Transcriptional profile of Bacillus subtilis sigF-mutant during vegetative growth and under sporulating conditions

Project description:Bacillus subtilis’ sigma factor F is the first forespore specific transcription factor and controls genes required for the early stages of prespore development. The role of sigF is well studied under conditions that induce sporulation. Here, the impact of a sigF disruption on the transcriptome of exponentially growing cultures is studied by micro-array analysis. This is relevant because in various experiments, such as industrial fermentation, prolonged experimental evolution or zero-growth studies, sporulation is an undesirable trait that should be avoided, e.g by a sigF mutation. Under conditions that typically don’t induce sporulation, the transcriptome showed minor signs of sporulation initiation. The number of genes differentially expressed and the magnitude of expression were, as expected, quite small in comparison with sporulation conditions. The genes mildly down-regulated were mostly involved in anabolism and the genes mildly up-regulated were mostly involved in catabolism, in particular fatty acid degradation genes. Probably this is related to the arrest at sporulation stage II occurring in the sigF mutant where additional energy is required for further growth of the polar compartments formed.

2015-09-30 | GSE64918 | GEO

Genome-wide Definition of the SigF Regulon in Mycobacterium tuberculosis

Project description:This SuperSeries is composed of the following subset Series: GSE34919: Genome-wide Definition of the SigF Regulon in Mycobacterium tuberculosis (ChIP-chip) GSE34922: Genome-wide Definition of the SigF Regulon in Mycobacterium tuberculosis (Expression) Refer to individual Series

2012-01-20 | E-GEOD-35080 | biostudies-arrayexpress

Caulobacter crescentus flagellins glycopeptides analyses

Project description:Caulobacter crescentus is an alphaproteobacterium that divides assymetrically. Each cell cycle results in the production of a motile flagellated cell and a sessile cell called the swamer cell and the stalked cell, respectively. The flagellar filament is composed of thousands polymerized flagellins. We showed that glycosylation of flagellins is required for the assembly of the flagellum. This glycosylation is performed by soluble FlmG glycosyltransferases that transfer nonulosonic acids (pseudaminic acid or legionaminic acid) directly to the flagellins. Such glycosylation system is also present in a close relative of Caulobacter crescentus, Brevundimonas subvibrioides. The project is to identify the site of glycosylation and the potential sugar added on this site.

2023-01-13 | PXD038730 | Pride

Comparison of the expression profiles of the 630E strain and a sigF mutant after 14h of growth

Project description:Compartment-specific control of gene expression during Bacillus subtilis sporulation is governed by a cascade of four sigma factors, sigmaF and sigmaG in the forespore and sigmaE and sigmaK in the mother cell. In this work, we combined transcriptional analyses and transcriptional start site mapping to define the sigmaF, sigmaE, sigmaG and sigmaK regulons in Clostridium difficile. A total of about 225 genes were under the control of these sigma factors: 25 in the sigmaF regulon, 97 sigmaE-dependent genes, 50 sigmaG-governed genes and 56 genes specifically controlled by sigmaK. A significant fraction of genes in each regulon are of unknown function and we can propose new candidates for spore coat proteins synthesized under the control of sigmaE and sigmaK among proteins previously detected in the spore proteome (Lawley et al., 2009 (PMID 19542279)). Global analysis of developmental gene expression under the control of these sigma factors indicate deviations from the B. subtilis model regarding the communication between mother cell and forespore in C. difficile. We show that the expression of the sigmaE regulon in the mother cell is not strictly under the control of sigmaF despite the fact that the forespore product SpoIIR is required for the processing of pro-sigmaE. In addition, the sigmaK regulon is not controlled by sigmaG in C. difficile in connection with the lack of pro-sigmaK processing in this bacterium. However, a control of the forespore on sigmaK targets is maintained through a sigmaF-dependent regulation of sigmaK-controlled genes, a process that bypasses sigmaG. Here, transcriptional profiling of the Clostridium difficile 630E strain vs. a sigE mutant after 14h of growth in MS is performed. Two-condition experiment: 630E strain 14h vs. sigF mutant 14h. 4 biological replicates for each condition, including dye-swaps.

2014-02-20 | E-GEOD-43199 | biostudies-arrayexpress

Genome-wide Definition of the SigF Regulon in Mycobacterium tuberculosis (ChIP-chip)

Project description:The genome wide ChIP-on-chip analysis to identify the DNA binding sites for the M.tuberculosis sigma factor Rv3286c (SigF)

2012-01-20 | GSE34919 | GEO

Genome-wide Definition of the SigF Regulon in Mycobacterium tuberculosis (ChIP-chip)

Project description:The genome wide ChIP-on-chip analysis to identify the DNA binding sites for the M.tuberculosis sigma factor Rv3286c (SigF) SigF binding sites were determined by microarray analysis of anti-sigF immunoprecipitated DNA from H37Rv(ΔrsbW/sigF)::pmySigF compared to H37Rv(ΔrsbW/sigF)::pMY769 (both cultured with pristinamycin for 3 days). 4 biological replicates were performed.

2012-01-20 | E-GEOD-34919 | biostudies-arrayexpress

Genome-wide Definition of the SigF Regulon in Mycobacterium tuberculosis (Expression)

Project description:The genome wide transcriptome analysis to identify the M.tuberculosis sigma factor Rv3286c (SigF) dependent transcripts as well as Pristimaycin induced transcripts

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Mycolicibacterium smegmatis MC2 155

Project description:Characterization of Mycobacterium smegmatis SigF regulon

| PRJNA121857 | ENA