Reactive oxygen species-inducible ECF σ factors of Bradyrhizobium japonicum.

Extracytoplasmic function (ECF) σ factors control the transcription of genes involved in different cellular functions, such as stress responses, metal homeostasis, virulence-related traits, and cell envelope structure. The genome of Bradyrhizobium japonicum, the nitrogen-fixing soybean endosymbiont,...

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Autores principales:	Nadezda Masloboeva, Luzia Reutimann, Philipp Stiefel, Rainer Follador, Nadja Leimer, Hauke Hennecke, Socorro Mesa, Hans-Martin Fischer
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Lenguaje:	EN
Publicado:	Public Library of Science (PLoS) 2012
Materias:	Medicine R Science Q
Acceso en línea:	https://doaj.org/article/aa37da31b9284ca9986168eb00ee10c8
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spelling	oai:doaj.org-article:aa37da31b9284ca9986168eb00ee10c82021-11-18T07:08:32ZReactive oxygen species-inducible ECF σ factors of Bradyrhizobium japonicum.1932-620310.1371/journal.pone.0043421https://doaj.org/article/aa37da31b9284ca9986168eb00ee10c82012-01-01T00:00:00Zhttps://www.ncbi.nlm.nih.gov/pmc/articles/pmid/22916258/?tool=EBIhttps://doaj.org/toc/1932-6203Extracytoplasmic function (ECF) σ factors control the transcription of genes involved in different cellular functions, such as stress responses, metal homeostasis, virulence-related traits, and cell envelope structure. The genome of Bradyrhizobium japonicum, the nitrogen-fixing soybean endosymbiont, encodes 17 putative ECF σ factors belonging to nine different ECF σ factor families. The genes for two of them, ecfQ (bll1028) and ecfF (blr3038), are highly induced in response to the reactive oxygen species hydrogen peroxide (H(2)O(2)) and singlet oxygen ((1)O(2)). The ecfF gene is followed by the predicted anti-σ factor gene osrA (blr3039). Mutants lacking EcfQ, EcfF plus OsrA, OsrA alone, or both σ factors plus OsrA were phenotypically characterized. While the symbiotic properties of all mutants were indistinguishable from the wild type, they showed increased sensitivity to singlet oxygen under free-living conditions. Possible target genes of EcfQ and EcfF were determined by microarray analyses, and candidate genes were compared with the H(2)O(2)-responsive regulon. These experiments disclosed that the two σ factors control rather small and, for the most part, distinct sets of genes, with about half of the genes representing 13% of the members of H(2)O(2)-responsive regulon. To get more insight into transcriptional regulation of both σ factors, the 5' ends of ecfQ and ecfF mRNA were determined. The presence of conserved sequence motifs in the promoter region of ecfQ and genes encoding EcfQ-like σ factors in related α-proteobacteria suggests regulation via a yet unknown transcription factor. By contrast, we have evidence that ecfF is autoregulated by transcription from an EcfF-dependent consensus promoter, and its product is negatively regulated via protein-protein interaction with OsrA. Conserved cysteine residues 129 and 179 of OsrA are required for normal function of OsrA. Cysteine 179 is essential for release of EcfF from an EcfF-OsrA complex upon H(2)O(2) stress while cysteine 129 is possibly needed for EcfF-OsrA interaction.Nadezda MasloboevaLuzia ReutimannPhilipp StiefelRainer FolladorNadja LeimerHauke HenneckeSocorro MesaHans-Martin FischerPublic Library of Science (PLoS)articleMedicineRScienceQENPLoS ONE, Vol 7, Iss 8, p e43421 (2012)
institution	DOAJ
collection	DOAJ
language	EN
topic	Medicine R Science Q
spellingShingle	Medicine R Science Q Nadezda Masloboeva Luzia Reutimann Philipp Stiefel Rainer Follador Nadja Leimer Hauke Hennecke Socorro Mesa Hans-Martin Fischer Reactive oxygen species-inducible ECF σ factors of Bradyrhizobium japonicum.
description	Extracytoplasmic function (ECF) σ factors control the transcription of genes involved in different cellular functions, such as stress responses, metal homeostasis, virulence-related traits, and cell envelope structure. The genome of Bradyrhizobium japonicum, the nitrogen-fixing soybean endosymbiont, encodes 17 putative ECF σ factors belonging to nine different ECF σ factor families. The genes for two of them, ecfQ (bll1028) and ecfF (blr3038), are highly induced in response to the reactive oxygen species hydrogen peroxide (H(2)O(2)) and singlet oxygen ((1)O(2)). The ecfF gene is followed by the predicted anti-σ factor gene osrA (blr3039). Mutants lacking EcfQ, EcfF plus OsrA, OsrA alone, or both σ factors plus OsrA were phenotypically characterized. While the symbiotic properties of all mutants were indistinguishable from the wild type, they showed increased sensitivity to singlet oxygen under free-living conditions. Possible target genes of EcfQ and EcfF were determined by microarray analyses, and candidate genes were compared with the H(2)O(2)-responsive regulon. These experiments disclosed that the two σ factors control rather small and, for the most part, distinct sets of genes, with about half of the genes representing 13% of the members of H(2)O(2)-responsive regulon. To get more insight into transcriptional regulation of both σ factors, the 5' ends of ecfQ and ecfF mRNA were determined. The presence of conserved sequence motifs in the promoter region of ecfQ and genes encoding EcfQ-like σ factors in related α-proteobacteria suggests regulation via a yet unknown transcription factor. By contrast, we have evidence that ecfF is autoregulated by transcription from an EcfF-dependent consensus promoter, and its product is negatively regulated via protein-protein interaction with OsrA. Conserved cysteine residues 129 and 179 of OsrA are required for normal function of OsrA. Cysteine 179 is essential for release of EcfF from an EcfF-OsrA complex upon H(2)O(2) stress while cysteine 129 is possibly needed for EcfF-OsrA interaction.
format	article
author	Nadezda Masloboeva Luzia Reutimann Philipp Stiefel Rainer Follador Nadja Leimer Hauke Hennecke Socorro Mesa Hans-Martin Fischer
author_facet	Nadezda Masloboeva Luzia Reutimann Philipp Stiefel Rainer Follador Nadja Leimer Hauke Hennecke Socorro Mesa Hans-Martin Fischer
author_sort	Nadezda Masloboeva
title	Reactive oxygen species-inducible ECF σ factors of Bradyrhizobium japonicum.
title_short	Reactive oxygen species-inducible ECF σ factors of Bradyrhizobium japonicum.
title_full	Reactive oxygen species-inducible ECF σ factors of Bradyrhizobium japonicum.
title_fullStr	Reactive oxygen species-inducible ECF σ factors of Bradyrhizobium japonicum.
title_full_unstemmed	Reactive oxygen species-inducible ECF σ factors of Bradyrhizobium japonicum.
title_sort	reactive oxygen species-inducible ecf σ factors of bradyrhizobium japonicum.
publisher	Public Library of Science (PLoS)
publishDate	2012
url	https://doaj.org/article/aa37da31b9284ca9986168eb00ee10c8
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Reactive oxygen species-inducible ECF σ factors of Bradyrhizobium japonicum.

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