Canonical and non-canonical EcfG sigma factors control the general stress response in Rhizobium etli
| Autor: | Ann Jans, Ivo Lambrichts, Jan Michiels, Maarten Fauvart, Kristof Engelen, Shanjun Gao, Maarten Vercruysse |
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| Přispěvatelé: | Jans, Ann, Vercruysse, Maarten, Gao, Shanjun, Engelen, Kristof, LAMBRICHTS, Ivo, Fauvart, Maarten, Michiels, Jan |
| Jazyk: | angličtina |
| Rok vydání: | 2013 |
| Předmět: |
STRUCTURAL BASIS
EXPRESSION alpha-proteobacteria Mutant TcrX 2-COMPONENT SYSTEM Sigma Factor Biology Models Biological Rhizobium etli Genome Microbiology ALARMONE PPGPP Stress Physiological Sigma factor CAULOBACTER-CRESCENTUS α-proteobacteria EcfG Gene Original Research Genetics Science & Technology Phylogenetic tree Gene Expression Regulation Bacterial Phenotype PHYR PhyR Response regulator ESCHERICHIA-COLI general stress response Settore AGR/16 - MICROBIOLOGIA AGRARIA FACTOR MIMICRY ECF sigma factor REGULATOR Life Sciences & Biomedicine |
| Zdroj: | MicrobiologyOpen |
| Popis: | A core component of the α-proteobacterial general stress response (GSR) is the extracytoplasmic function (ECF) sigma factor EcfG, exclusively present in this taxonomic class. Half of the completed α-proteobacterial genome sequences contain two or more copies of genes encoding σEcfG-like sigma factors, with the primary copy typically located adjacent to genes coding for a cognate anti-sigma factor (NepR) and two-component response regulator (PhyR). So far, the widespread occurrence of additional, non-canonical σEcfG copies has not satisfactorily been explained. This study explores the hierarchical relation between Rhizobium etli σEcfG1 and σEcfG2, canonical and non-canonical σEcfG proteins, respectively. Contrary to reports in other species, we find that σEcfG1 and σEcfG2 act in parallel, as nodes of a complex regulatory network, rather than in series, as elements of a linear regulatory cascade. We demonstrate that both sigma factors control unique yet also shared target genes, corroborating phenotypic evidence. σEcfG1 drives expression of rpoH2, explaining the increased heat sensitivity of an ecfG1 mutant, while katG is under control of σEcfG2, accounting for reduced oxidative stress resistance of an ecfG2 mutant. We also identify non-coding RNA genes as novel σEcfG targets. We propose a modified model for GSR regulation in R. etli, in which σEcfG1 and σEcfG2 function largely independently. Based on a phylogenetic analysis and considering the prevalence of α-proteobacterial genomes with multiple σEcfG copies, this model may also be applicable to numerous other species. This research has been funded by the Interuniversity Attraction Poles Programme initiated by the Belgian Science Policy Office and was supported by grants from the Research Council of the KU Leuven (GOA/011/2008) and from the Fund for Scientific Research-Flanders (G.0412.10). |
| Databáze: | OpenAIRE |
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