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The Burkholderia cenocepacia iron starvation σ factor, OrbS, possesses an on-board iron sensor
Burkholderia cenocepacia is an opportunistic pathogen that causes severe infections of the cystic fibrosis (CF) lung. To acquire iron, B. cenocepacia secretes the Fe(III)-binding compound, ornibactin. Genes for synthesis and utilisation of ornibactin are served by the iron starvation (IS) extracytop...
Autores principales: | , , , , , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Oxford University Press
2022
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9023288/ https://www.ncbi.nlm.nih.gov/pubmed/35234897 http://dx.doi.org/10.1093/nar/gkac137 |
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author | Butt, Aaron T Banyard, Christopher D Haldipurkar, Sayali S Agnoli, Kirsty Mohsin, Muslim I Vitovski, Srdjan Paleja, Ameya Tang, Yingzhi Lomax, Rebecca Ye, Fuzhou Green, Jeffrey Thomas, Mark S |
author_facet | Butt, Aaron T Banyard, Christopher D Haldipurkar, Sayali S Agnoli, Kirsty Mohsin, Muslim I Vitovski, Srdjan Paleja, Ameya Tang, Yingzhi Lomax, Rebecca Ye, Fuzhou Green, Jeffrey Thomas, Mark S |
author_sort | Butt, Aaron T |
collection | PubMed |
description | Burkholderia cenocepacia is an opportunistic pathogen that causes severe infections of the cystic fibrosis (CF) lung. To acquire iron, B. cenocepacia secretes the Fe(III)-binding compound, ornibactin. Genes for synthesis and utilisation of ornibactin are served by the iron starvation (IS) extracytoplasmic function (ECF) σ factor, OrbS. Transcription of orbS is regulated in response to the prevailing iron concentration by the ferric uptake regulator (Fur), such that orbS expression is repressed under iron-sufficient conditions. Here we show that, in addition to Fur-mediated regulation of orbS, the OrbS protein itself responds to intracellular iron availability. Substitution of cysteine residues in the C-terminal region of OrbS diminished the ability to respond to Fe(II) in vivo. Accordingly, whilst Fe(II) impaired transcription from and recognition of OrbS-dependent promoters in vitro by inhibiting the binding of OrbS to core RNA polymerase (RNAP), the cysteine-substituted OrbS variant was less responsive to Fe(II). Thus, the cysteine residues within the C-terminal region of OrbS contribute to an iron-sensing motif that serves as an on-board ‘anti-σ factor’ in the presence of Fe(II). A model to account for the presence two regulators (Fur and OrbS) that respond to the same intracellular Fe(II) signal to control ornibactin synthesis and utilisation is discussed. |
format | Online Article Text |
id | pubmed-9023288 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2022 |
publisher | Oxford University Press |
record_format | MEDLINE/PubMed |
spelling | pubmed-90232882022-04-22 The Burkholderia cenocepacia iron starvation σ factor, OrbS, possesses an on-board iron sensor Butt, Aaron T Banyard, Christopher D Haldipurkar, Sayali S Agnoli, Kirsty Mohsin, Muslim I Vitovski, Srdjan Paleja, Ameya Tang, Yingzhi Lomax, Rebecca Ye, Fuzhou Green, Jeffrey Thomas, Mark S Nucleic Acids Res Gene regulation, Chromatin and Epigenetics Burkholderia cenocepacia is an opportunistic pathogen that causes severe infections of the cystic fibrosis (CF) lung. To acquire iron, B. cenocepacia secretes the Fe(III)-binding compound, ornibactin. Genes for synthesis and utilisation of ornibactin are served by the iron starvation (IS) extracytoplasmic function (ECF) σ factor, OrbS. Transcription of orbS is regulated in response to the prevailing iron concentration by the ferric uptake regulator (Fur), such that orbS expression is repressed under iron-sufficient conditions. Here we show that, in addition to Fur-mediated regulation of orbS, the OrbS protein itself responds to intracellular iron availability. Substitution of cysteine residues in the C-terminal region of OrbS diminished the ability to respond to Fe(II) in vivo. Accordingly, whilst Fe(II) impaired transcription from and recognition of OrbS-dependent promoters in vitro by inhibiting the binding of OrbS to core RNA polymerase (RNAP), the cysteine-substituted OrbS variant was less responsive to Fe(II). Thus, the cysteine residues within the C-terminal region of OrbS contribute to an iron-sensing motif that serves as an on-board ‘anti-σ factor’ in the presence of Fe(II). A model to account for the presence two regulators (Fur and OrbS) that respond to the same intracellular Fe(II) signal to control ornibactin synthesis and utilisation is discussed. Oxford University Press 2022-03-02 /pmc/articles/PMC9023288/ /pubmed/35234897 http://dx.doi.org/10.1093/nar/gkac137 Text en © The Author(s) 2022. Published by Oxford University Press on behalf of Nucleic Acids Research. https://creativecommons.org/licenses/by/4.0/This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited. |
spellingShingle | Gene regulation, Chromatin and Epigenetics Butt, Aaron T Banyard, Christopher D Haldipurkar, Sayali S Agnoli, Kirsty Mohsin, Muslim I Vitovski, Srdjan Paleja, Ameya Tang, Yingzhi Lomax, Rebecca Ye, Fuzhou Green, Jeffrey Thomas, Mark S The Burkholderia cenocepacia iron starvation σ factor, OrbS, possesses an on-board iron sensor |
title | The Burkholderia cenocepacia iron starvation σ factor, OrbS, possesses an on-board iron sensor |
title_full | The Burkholderia cenocepacia iron starvation σ factor, OrbS, possesses an on-board iron sensor |
title_fullStr | The Burkholderia cenocepacia iron starvation σ factor, OrbS, possesses an on-board iron sensor |
title_full_unstemmed | The Burkholderia cenocepacia iron starvation σ factor, OrbS, possesses an on-board iron sensor |
title_short | The Burkholderia cenocepacia iron starvation σ factor, OrbS, possesses an on-board iron sensor |
title_sort | burkholderia cenocepacia iron starvation σ factor, orbs, possesses an on-board iron sensor |
topic | Gene regulation, Chromatin and Epigenetics |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9023288/ https://www.ncbi.nlm.nih.gov/pubmed/35234897 http://dx.doi.org/10.1093/nar/gkac137 |
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