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Regulation of the phototrophic iron oxidation (pio) genes in Rhodopseudomonas palustris TIE-1 is mediated by the global regulator, FixK
The pioABC operon is required for phototrophic iron oxidative (photoferrotrophic) growth by the αproteobacterium Rhodopseudomonas palustris TIE-1. Expression analysis of this operon showed that it was transcribed and translated during anaerobic growth, upregulation being observed only under photofer...
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Formato: | Texto |
Lenguaje: | English |
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Blackwell Publishing Ltd
2011
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3050613/ https://www.ncbi.nlm.nih.gov/pubmed/21166894 http://dx.doi.org/10.1111/j.1365-2958.2010.07430.x |
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author | Bose, Arpita Newman Dianne, K |
author_facet | Bose, Arpita Newman Dianne, K |
author_sort | Bose, Arpita |
collection | PubMed |
description | The pioABC operon is required for phototrophic iron oxidative (photoferrotrophic) growth by the αproteobacterium Rhodopseudomonas palustris TIE-1. Expression analysis of this operon showed that it was transcribed and translated during anaerobic growth, upregulation being observed only under photoferrotrophic conditions. Very low levels of transcription were observed during aerobic growth, suggesting expression was induced by anoxia. The presence of two canonical FixK boxes upstream of the identified pioABC transcription start site implicated FixK as a likely regulator. To test this possibility, a δfixK mutant of R. palustris TIE-1 was assessed for pioABC expression. pioABC expression decreased dramatically in δfixK versus WT during photoferrotrophic growth, implying that FixK positively regulates its expression; coincidently, the onset of iron oxidation was prolonged in this mutant. In contrast, pioABC expression increased in δfixK under all non-photoferrotrophic conditions tested, suggesting the presence of additional levels of regulation. Purified FixK directly bound only the proximal FixK box in gel mobility-shift assays. Mutant expression analysis revealed that FixK regulates anaerobic phototrophic expression of other target genes with FixK binding sites in their promoters. This study shows that FixK regulates key iron metabolism genes in an αproteobacterium, pointing to a departure from the canonical Fur/Irr mode of regulation. |
format | Text |
id | pubmed-3050613 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2011 |
publisher | Blackwell Publishing Ltd |
record_format | MEDLINE/PubMed |
spelling | pubmed-30506132011-07-01 Regulation of the phototrophic iron oxidation (pio) genes in Rhodopseudomonas palustris TIE-1 is mediated by the global regulator, FixK Bose, Arpita Newman Dianne, K Mol Microbiol Research Articles The pioABC operon is required for phototrophic iron oxidative (photoferrotrophic) growth by the αproteobacterium Rhodopseudomonas palustris TIE-1. Expression analysis of this operon showed that it was transcribed and translated during anaerobic growth, upregulation being observed only under photoferrotrophic conditions. Very low levels of transcription were observed during aerobic growth, suggesting expression was induced by anoxia. The presence of two canonical FixK boxes upstream of the identified pioABC transcription start site implicated FixK as a likely regulator. To test this possibility, a δfixK mutant of R. palustris TIE-1 was assessed for pioABC expression. pioABC expression decreased dramatically in δfixK versus WT during photoferrotrophic growth, implying that FixK positively regulates its expression; coincidently, the onset of iron oxidation was prolonged in this mutant. In contrast, pioABC expression increased in δfixK under all non-photoferrotrophic conditions tested, suggesting the presence of additional levels of regulation. Purified FixK directly bound only the proximal FixK box in gel mobility-shift assays. Mutant expression analysis revealed that FixK regulates anaerobic phototrophic expression of other target genes with FixK binding sites in their promoters. This study shows that FixK regulates key iron metabolism genes in an αproteobacterium, pointing to a departure from the canonical Fur/Irr mode of regulation. Blackwell Publishing Ltd 2011-01 2010-10-28 /pmc/articles/PMC3050613/ /pubmed/21166894 http://dx.doi.org/10.1111/j.1365-2958.2010.07430.x Text en © 2010 Blackwell Publishing Ltd http://creativecommons.org/licenses/by/2.5/ Re-use of this article is permitted in accordance with the Creative Commons Deed, Attribution 2.5, which does not permit commercial exploitation. |
spellingShingle | Research Articles Bose, Arpita Newman Dianne, K Regulation of the phototrophic iron oxidation (pio) genes in Rhodopseudomonas palustris TIE-1 is mediated by the global regulator, FixK |
title | Regulation of the phototrophic iron oxidation (pio) genes in Rhodopseudomonas palustris TIE-1 is mediated by the global regulator, FixK |
title_full | Regulation of the phototrophic iron oxidation (pio) genes in Rhodopseudomonas palustris TIE-1 is mediated by the global regulator, FixK |
title_fullStr | Regulation of the phototrophic iron oxidation (pio) genes in Rhodopseudomonas palustris TIE-1 is mediated by the global regulator, FixK |
title_full_unstemmed | Regulation of the phototrophic iron oxidation (pio) genes in Rhodopseudomonas palustris TIE-1 is mediated by the global regulator, FixK |
title_short | Regulation of the phototrophic iron oxidation (pio) genes in Rhodopseudomonas palustris TIE-1 is mediated by the global regulator, FixK |
title_sort | regulation of the phototrophic iron oxidation (pio) genes in rhodopseudomonas palustris tie-1 is mediated by the global regulator, fixk |
topic | Research Articles |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3050613/ https://www.ncbi.nlm.nih.gov/pubmed/21166894 http://dx.doi.org/10.1111/j.1365-2958.2010.07430.x |
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