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Transcriptional mechanisms for differential expression of outer membrane cytochrome genes omcA and mtrC in Shewanella oneidensis MR-1
BACKGROUND: Shewanella oneidensis MR-1 is capable of reducing extracellular electron acceptors, such as metals and electrodes, through the Mtr respiratory pathway, which consists of the outer membrane cytochromes OmcA and MtrC and associated proteins MtrA and MtrB. These proteins are encoded in the...
Autores principales: | , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
BioMed Central
2015
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4417206/ https://www.ncbi.nlm.nih.gov/pubmed/25886963 http://dx.doi.org/10.1186/s12866-015-0406-8 |
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author | Kasai, Takuya Kouzuma, Atsushi Nojiri, Hideaki Watanabe, Kazuya |
author_facet | Kasai, Takuya Kouzuma, Atsushi Nojiri, Hideaki Watanabe, Kazuya |
author_sort | Kasai, Takuya |
collection | PubMed |
description | BACKGROUND: Shewanella oneidensis MR-1 is capable of reducing extracellular electron acceptors, such as metals and electrodes, through the Mtr respiratory pathway, which consists of the outer membrane cytochromes OmcA and MtrC and associated proteins MtrA and MtrB. These proteins are encoded in the mtr gene cluster (omcA-mtrCAB) in the MR-1 chromosome. RESULTS: Here, we investigated the transcriptional mechanisms for the mtr genes and demonstrated that omcA and mtrC are transcribed from two upstream promoters, P(omcA) and P(mtrC), respectively. In vivo transcription and in vitro electrophoretic mobility shift assays revealed that a cAMP receptor protein (CRP) positively regulates the expression of the mtr genes by binding to the upstream regions of P(omcA) and P(mtrC). However, the expression of omcA and mtrC was differentially regulated in response to culture conditions; specifically, the expression from P(mtrC) was higher under aerobic conditions than that under anaerobic conditions with fumarate as an electron acceptor, whereas expression from P(omcA) exhibited the opposite trend. Deletion of the region upstream of the CRP-binding site of P(omcA) resulted in a significant increase in promoter activity under aerobic conditions, demonstrating that the deleted region is involved in the negative regulation of P(omcA). CONCLUSIONS: Taken together, the present results indicate that transcription of the mtr genes is regulated by multiple promoters and regulatory systems, including the CRP/cAMP-dependent regulatory system and yet-unidentified negative regulators. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12866-015-0406-8) contains supplementary material, which is available to authorized users. |
format | Online Article Text |
id | pubmed-4417206 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2015 |
publisher | BioMed Central |
record_format | MEDLINE/PubMed |
spelling | pubmed-44172062015-05-03 Transcriptional mechanisms for differential expression of outer membrane cytochrome genes omcA and mtrC in Shewanella oneidensis MR-1 Kasai, Takuya Kouzuma, Atsushi Nojiri, Hideaki Watanabe, Kazuya BMC Microbiol Research Article BACKGROUND: Shewanella oneidensis MR-1 is capable of reducing extracellular electron acceptors, such as metals and electrodes, through the Mtr respiratory pathway, which consists of the outer membrane cytochromes OmcA and MtrC and associated proteins MtrA and MtrB. These proteins are encoded in the mtr gene cluster (omcA-mtrCAB) in the MR-1 chromosome. RESULTS: Here, we investigated the transcriptional mechanisms for the mtr genes and demonstrated that omcA and mtrC are transcribed from two upstream promoters, P(omcA) and P(mtrC), respectively. In vivo transcription and in vitro electrophoretic mobility shift assays revealed that a cAMP receptor protein (CRP) positively regulates the expression of the mtr genes by binding to the upstream regions of P(omcA) and P(mtrC). However, the expression of omcA and mtrC was differentially regulated in response to culture conditions; specifically, the expression from P(mtrC) was higher under aerobic conditions than that under anaerobic conditions with fumarate as an electron acceptor, whereas expression from P(omcA) exhibited the opposite trend. Deletion of the region upstream of the CRP-binding site of P(omcA) resulted in a significant increase in promoter activity under aerobic conditions, demonstrating that the deleted region is involved in the negative regulation of P(omcA). CONCLUSIONS: Taken together, the present results indicate that transcription of the mtr genes is regulated by multiple promoters and regulatory systems, including the CRP/cAMP-dependent regulatory system and yet-unidentified negative regulators. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12866-015-0406-8) contains supplementary material, which is available to authorized users. BioMed Central 2015-03-21 /pmc/articles/PMC4417206/ /pubmed/25886963 http://dx.doi.org/10.1186/s12866-015-0406-8 Text en © Kasai et al.; licensee BioMed Central. 2015 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. |
spellingShingle | Research Article Kasai, Takuya Kouzuma, Atsushi Nojiri, Hideaki Watanabe, Kazuya Transcriptional mechanisms for differential expression of outer membrane cytochrome genes omcA and mtrC in Shewanella oneidensis MR-1 |
title | Transcriptional mechanisms for differential expression of outer membrane cytochrome genes omcA and mtrC in Shewanella oneidensis MR-1 |
title_full | Transcriptional mechanisms for differential expression of outer membrane cytochrome genes omcA and mtrC in Shewanella oneidensis MR-1 |
title_fullStr | Transcriptional mechanisms for differential expression of outer membrane cytochrome genes omcA and mtrC in Shewanella oneidensis MR-1 |
title_full_unstemmed | Transcriptional mechanisms for differential expression of outer membrane cytochrome genes omcA and mtrC in Shewanella oneidensis MR-1 |
title_short | Transcriptional mechanisms for differential expression of outer membrane cytochrome genes omcA and mtrC in Shewanella oneidensis MR-1 |
title_sort | transcriptional mechanisms for differential expression of outer membrane cytochrome genes omca and mtrc in shewanella oneidensis mr-1 |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4417206/ https://www.ncbi.nlm.nih.gov/pubmed/25886963 http://dx.doi.org/10.1186/s12866-015-0406-8 |
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