The Sinorhizobium meliloti SyrM regulon: effects on global gene expression are mediated by syrA and nodD3
Ontology highlight
ABSTRACT:
ORGANISM(S): Sinorhizobium meliloti
SUBMITTER: Melanie Barnett
PROVIDER: E-GEOD-61526 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
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Project description:We characterized transcriptomes of a strain overexpressing syrA. Our work shows that the syrA transcriptome shares similar gene expression changes to the syrM and nodD3 transcriptomes and that nodD3 and syrA may be the only targets directly activated by SyrM. We propose that most of the gene expression changes observed when nodD3 is overexpressed are due to NodD3 activation of syrM expression, which in turn stimulates SyrM activation of syrA expression. The subsequent increase in SyrA abundance alters activity of the ChvI-ExoS-ExoR circuit, resulting in broad changes in gene expression. Gene expression profiling of Sinorhizobium meliloti overexpressing syrA was performed using custom Affymetrix GeneChips
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Project description:We characterized transcriptomes of a strain overexpressing syrM. Our work shows that the syrM transcriptome shares similar gene expression changes to the syrA and nodD3 transcriptomes and that nodD3 and syrA may be the only targets directly activated by SyrM. We propose that most of the gene expression changes observed when nodD3 is overexpressed are due to NodD3 activation of syrM expression, which in turn stimulates SyrM activation of syrA expression. The subsequent increase in SyrA abundance alters activity of the ChvI-ExoS-ExoR circuit, resulting in broad changes in gene expression. Gene expression profiling of a Sinorhizobium meliloti nodD1, nodD2, nodD3 mutant overexpressing syrM was performed using custom Affymetrix GeneChips
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Project description:Sinorhizobium meliloti can live as a soil saprophyte, and can engage in a nitrogen fixing symbiosis with plant roots. To succeed in such diverse environments, the bacteria must continually adjust gene expression. Transcriptional plasticity in eubacteria is often mediated by alternative sigma factors interacting with core RNA polymerase. The S. meliloti genome encodes 14 of these alternative sigmas, including two putative RpoH (heat shock) sigmas. We used custom Affymetrix Symbiosis Chips to characterize the global transcriptional response of S. meliloti rpoH1, rpoH2 and rpoH1 rpoH2 mutants during heat shock and stationary phase growth. Under these conditions, expression of over 300 genes is dependent on rpoH1 and rpoH2. Gene expression profiling of Sinorhizobium meliloti Rm1021 and its isogenic rpoH1, rpoH2, and rpoH1rpoH2 mutants, subjected to heat shock or stationary phase growth, was performed using custom Affymetrix GeneChips
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