Repression by the H-NS/YmoA histone-like protein complex enables IscR dependent regulation of the Yersinia T3SS.
The type III secretion system (T3SS) is an appendage used by many bacterial pathogens, such as pathogenic Yersinia, to subvert host defenses. However, because the T3SS is energetically costly and immunogenic, it must be tightly regulated in response to environmental cues to enable survival in the ho...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Public Library of Science (PLoS)
2022-07-01
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| Series: | PLoS Genetics |
| Online Access: | https://doi.org/10.1371/journal.pgen.1010321 |
| _version_ | 1797894582656040960 |
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| author | David Balderas Mané Ohanyan Pablo A Alvarez Erin Mettert Natasha Tanner Patricia J Kiley Victoria Auerbuch |
| author_facet | David Balderas Mané Ohanyan Pablo A Alvarez Erin Mettert Natasha Tanner Patricia J Kiley Victoria Auerbuch |
| author_sort | David Balderas |
| collection | DOAJ |
| description | The type III secretion system (T3SS) is an appendage used by many bacterial pathogens, such as pathogenic Yersinia, to subvert host defenses. However, because the T3SS is energetically costly and immunogenic, it must be tightly regulated in response to environmental cues to enable survival in the host. Here we show that expression of the Yersinia Ysc T3SS master regulator, LcrF, is orchestrated by the opposing activities of the repressive H-NS/YmoA histone-like protein complex and induction by the iron and oxygen-regulated IscR transcription factor. While deletion of iscR or ymoA has been shown to decrease and increase LcrF expression and type III secretion, respectively, the role of H-NS in this system has not been definitively established because hns is an essential gene in Yersinia. Using CRISPRi knockdown of hns, we show that hns depletion causes derepression of lcrF. Furthermore, we find that while YmoA is dispensable for H-NS binding to the lcrF promoter, YmoA binding to H-NS is important for H-NS repressive activity. We bioinformatically identified three H-NS binding regions within the lcrF promoter and demonstrate binding of H-NS to these sites in vivo using chromatin immunoprecipitation. Using promoter truncation and binding site mutation analysis, we show that two of these H-NS binding regions are important for H-NS/YmoA-mediated repression of the lcrF promoter. Surprisingly, we find that IscR is dispensable for lcrF transcription in the absence of H-NS/YmoA. Indeed, IscR-dependent regulation of LcrF and type III secretion in response to changes in oxygen, such as those Yersinia is predicted to experience during host infection, only occurs in the presence of an H-NS/YmoA complex. These data suggest that, in the presence of host tissue cues that drive sufficient IscR expression, IscR can act as a roadblock to H-NS/YmoA-dependent repression of RNA polymerase at the lcrF promoter to turn on T3SS expression. |
| first_indexed | 2024-04-10T07:12:40Z |
| format | Article |
| id | doaj.art-31175d260d99424d9eccf832051d18ce |
| institution | Directory Open Access Journal |
| issn | 1553-7390 1553-7404 |
| language | English |
| last_indexed | 2024-04-10T07:12:40Z |
| publishDate | 2022-07-01 |
| publisher | Public Library of Science (PLoS) |
| record_format | Article |
| series | PLoS Genetics |
| spelling | doaj.art-31175d260d99424d9eccf832051d18ce2023-02-26T05:31:22ZengPublic Library of Science (PLoS)PLoS Genetics1553-73901553-74042022-07-01187e101032110.1371/journal.pgen.1010321Repression by the H-NS/YmoA histone-like protein complex enables IscR dependent regulation of the Yersinia T3SS.David BalderasMané OhanyanPablo A AlvarezErin MettertNatasha TannerPatricia J KileyVictoria AuerbuchThe type III secretion system (T3SS) is an appendage used by many bacterial pathogens, such as pathogenic Yersinia, to subvert host defenses. However, because the T3SS is energetically costly and immunogenic, it must be tightly regulated in response to environmental cues to enable survival in the host. Here we show that expression of the Yersinia Ysc T3SS master regulator, LcrF, is orchestrated by the opposing activities of the repressive H-NS/YmoA histone-like protein complex and induction by the iron and oxygen-regulated IscR transcription factor. While deletion of iscR or ymoA has been shown to decrease and increase LcrF expression and type III secretion, respectively, the role of H-NS in this system has not been definitively established because hns is an essential gene in Yersinia. Using CRISPRi knockdown of hns, we show that hns depletion causes derepression of lcrF. Furthermore, we find that while YmoA is dispensable for H-NS binding to the lcrF promoter, YmoA binding to H-NS is important for H-NS repressive activity. We bioinformatically identified three H-NS binding regions within the lcrF promoter and demonstrate binding of H-NS to these sites in vivo using chromatin immunoprecipitation. Using promoter truncation and binding site mutation analysis, we show that two of these H-NS binding regions are important for H-NS/YmoA-mediated repression of the lcrF promoter. Surprisingly, we find that IscR is dispensable for lcrF transcription in the absence of H-NS/YmoA. Indeed, IscR-dependent regulation of LcrF and type III secretion in response to changes in oxygen, such as those Yersinia is predicted to experience during host infection, only occurs in the presence of an H-NS/YmoA complex. These data suggest that, in the presence of host tissue cues that drive sufficient IscR expression, IscR can act as a roadblock to H-NS/YmoA-dependent repression of RNA polymerase at the lcrF promoter to turn on T3SS expression.https://doi.org/10.1371/journal.pgen.1010321 |
| spellingShingle | David Balderas Mané Ohanyan Pablo A Alvarez Erin Mettert Natasha Tanner Patricia J Kiley Victoria Auerbuch Repression by the H-NS/YmoA histone-like protein complex enables IscR dependent regulation of the Yersinia T3SS. PLoS Genetics |
| title | Repression by the H-NS/YmoA histone-like protein complex enables IscR dependent regulation of the Yersinia T3SS. |
| title_full | Repression by the H-NS/YmoA histone-like protein complex enables IscR dependent regulation of the Yersinia T3SS. |
| title_fullStr | Repression by the H-NS/YmoA histone-like protein complex enables IscR dependent regulation of the Yersinia T3SS. |
| title_full_unstemmed | Repression by the H-NS/YmoA histone-like protein complex enables IscR dependent regulation of the Yersinia T3SS. |
| title_short | Repression by the H-NS/YmoA histone-like protein complex enables IscR dependent regulation of the Yersinia T3SS. |
| title_sort | repression by the h ns ymoa histone like protein complex enables iscr dependent regulation of the yersinia t3ss |
| url | https://doi.org/10.1371/journal.pgen.1010321 |
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