Role of the extracytoplasmic-function sigma Factor sigmaH in Mycobacterium tuberculosis global gene expression
Ontology highlight
ABSTRACT:
ORGANISM(S): Mycobacterium tuberculosis
PROVIDER: GSE8689 | GEO | 2007/08/04
SECONDARY ACCESSION(S): PRJNA101907
REPOSITORIES: GEO
Similar Datasets
Project description:Like other bacterial species, Mycobacterium tuberculosis has multiple sigma (s) factors encoded in its genome. In previously published work, we and others have shown that mutations in some of these transcriptional activators render M. tuberculosis sensitive to various environmental stresses and, in some cases, cause attenuated virulence phenotypes. In this paper, we characterize a M. tuberculosis mutant lacking the ECF s factor sigma-H. This mutant was more sensitive than the wild type to heat shock and to various oxidative stresses, but did not show decreased ability to grow inside macrophages. Using quantitative reverse transcription-PCR and microarray technology, we have started to define the sigma-H regulon and its involvement in the global regulation of the response to heat shock and the thiol-specific oxidizing agent diamide. We identified 48 genes whose expression increased after exposure of M. tuberculosis to diamide; out of these, 39 were not induced in the sigH mutant, showing their direct or indirect dependence on sigma-H. Some of these genes encode proteins whose predicted function is related to thiol metabolism, such as thioredoxin, thioredoxin reductase and enzymes involved in cysteine and molybdopterine biosynthesis. Other genes under sigma-H control encode transcriptional regulators such as sigB, sigE, and sigH itself.
2007-09-12 | E-TABM-316 | biostudies-arrayexpress
Project description:Like other bacterial species, Mycobacterium tuberculosis has multiple sigma (s) factors encoded in its genome. In previously published work, we and others have shown that mutations in some of these transcriptional activators render M. tuberculosis sensitive to various environmental stresses and, in some cases, cause attenuated virulence phenotypes. In this paper, we characterize a M. tuberculosis mutant lacking the ECF s factor sigma-H. This mutant was more sensitive than the wild type to heat shock and to various oxidative stresses, but did not show decreased ability to grow inside macrophages. Using quantitative reverse transcription-PCR and microarray technology, we have started to define the sigma-H regulon and its involvement in the global regulation of the response to heat shock and the thiol-specific oxidizing agent diamide. We identified 48 genes whose expression increased after exposure of M. tuberculosis to diamide; out of these, 39 were not induced in the sigH mutant, showing their direct or indirect dependence on sigma-H. Some of these genes encode proteins whose predicted function is related to thiol metabolism, such as thioredoxin, thioredoxin reductase and enzymes involved in cysteine and molybdopterine biosynthesis. Other genes under sigma-H control encode transcriptional regulators such as sigB, sigE, and sigH itself. Keywords: comparative genome hybridization design and genetic modification design 15 samples were analyzed. The quality controls were biological replicate and technical replicate
2007-08-03 | E-GEOD-8689 | biostudies-arrayexpress
Project description:In previously published work, we identified three Mycobacterium tuberculosis sigma (s) factor genes responding to heat shock (sigB, sigE and sigH ). Two of them (sigB and sigE ) also responded to SDS exposure. As these responses to stress suggested that the s factors encoded by these genes could be involved in pathogenicity, we are studying their role in physiology and virulence. In this work, we characterize a sigE mutant of M. tuberculosis H37Rv. The sigE mutant strain was more sensitive than the wild-type strain to heat shock, SDS and various oxidative stresses. It was also defective in the ability to grow inside both human and murine unactivated macrophages and was more sensitive than the wild-type strain to the killing activity of activated murine macrophages. Using microarray technology and quantitative reverse transcriptionÐpolymerase chain reaction (RTÐPCR), we started to define the sigmaE regulon of M. tuberculosis and its involvement in the global regulation of the stress induced by SDS. We showed the requirement for a functional sigE gene for full expression of sigB and for its induction after SDS exposure but not after heat shock. We also identified several genes that are no longer induced when sigmaE is absent. These genes encode proteins belonging to different classes including transcriptional regulators, enzymes involved in fatty acid degradation and classical heat shock proteins.
2007-09-12 | E-TABM-313 | biostudies-arrayexpress
Project description:In previously published work, we identified three Mycobacterium tuberculosis sigma (s) factor genes responding to heat shock (sigB, sigE and sigH ). Two of them (sigB and sigE ) also responded to SDS exposure. As these responses to stress suggested that the s factors encoded by these genes could be involved in pathogenicity, we are studying their role in physiology and virulence. In this work, we characterize a sigE mutant of M. tuberculosis H37Rv. The sigE mutant strain was more sensitive than the wild-type strain to heat shock, SDS and various oxidative stresses. It was also defective in the ability to grow inside both human and murine unactivated macrophages and was more sensitive than the wild-type strain to the killing activity of activated murine macrophages. Using microarray technology and quantitative reverse transcriptionÐpolymerase chain reaction (RTÐPCR), we started to define the sigmaE regulon of M. tuberculosis and its involvement in the global regulation of the stress induced by SDS. We showed the requirement for a functional sigE gene for full expression of sigB and for its induction after SDS exposure but not after heat shock. We also identified several genes that are no longer induced when sigmaE is absent. These genes encode proteins belonging to different classes including transcriptional regulators, enzymes involved in fatty acid degradation and classical heat shock proteins. Keywords: genetic modification design and comparative genome hybridization design
2007-08-03 | GSE8664 | GEO
Project description:In previously published work, we identified three Mycobacterium tuberculosis sigma (s) factor genes responding to heat shock (sigB, sigE and sigH ). Two of them (sigB and sigE ) also responded to SDS exposure. As these responses to stress suggested that the s factors encoded by these genes could be involved in pathogenicity, we are studying their role in physiology and virulence. In this work, we characterize a sigE mutant of M. tuberculosis H37Rv. The sigE mutant strain was more sensitive than the wild-type strain to heat shock, SDS and various oxidative stresses. It was also defective in the ability to grow inside both human and murine unactivated macrophages and was more sensitive than the wild-type strain to the killing activity of activated murine macrophages. Using microarray technology and quantitative reverse transcriptionÐpolymerase chain reaction (RTÐPCR), we started to define the sigmaE regulon of M. tuberculosis and its involvement in the global regulation of the stress induced by SDS. We showed the requirement for a functional sigE gene for full expression of sigB and for its induction after SDS exposure but not after heat shock. We also identified several genes that are no longer induced when sigmaE is absent. These genes encode proteins belonging to different classes including transcriptional regulators, enzymes involved in fatty acid degradation and classical heat shock proteins. Keywords: genetic modification design and comparative genome hybridization design 15 samples were analyzed. The quality controls were biological replicate and technical replicate
2007-08-02 | E-GEOD-8664 | biostudies-arrayexpress
Project description:Mycobacterium avium subspecies paratuberculosis (a.k.a. M. paratuberculosis) causes JohneM-bM-^@M-^Ys disease, an enteric infection in cattle and other ruminants, greatly afflicting the dairy industry worldwide. Once inside the cell, M. paratuberculosis is known to survive harsh microenvironments, especially those inside activated macrophages. To improve our understanding of M. paratuberculosis pathogenesis, we examined the phagosome maturation associated with transcriptional responses of M. paratuberculosis during macrophage infection. Monitoring cellular markers, only live M. paratuberculosis bacilli were able to prevent phagosome maturation and reduce its acidification. On the transcriptional level, over 300 of M. paratuberculosis genes were significantly, differentially regulated in both naM-CM-/ve and IFN-M-NM-3-activated macrophages. These genes include the sigma factor H (sigH) that was shown to be important during persistent infection in M. tuberculosis. Interestingly, a sigH-knockout mutant showed increased sensitivity to a sustained level of thiol-specific oxidative stress. Large-scale RNA sequence analysis revealed that a large number of genes belong to the sigH regulon, especially following diamide stress. Genes involved in oxidative stress and virulence were among the induced genes in the sigH regulon with a putative consensus sequence for SigH binding was recognized in a subset of these genes (N=30), suggesting direct regulation with SigH. Finally, mice infections showed a significant attenuation of the M-bM-^HM-^FsigH mutant compared to its parental strain suggesting a role for sigH in M. paratuberculosis virulence. Such analysis could identify potential targets for further testing as vaccine candidates against JohneM-bM-^@M-^Ys disease. Examination of role played by alternative sigma factor, SigH during M. paratuberculosis infection.
2012-12-29 | E-GEOD-43182 | biostudies-arrayexpress
Project description:Mycobacterium avium subspecies paratuberculosis (a.k.a. M. paratuberculosis) causes Johne’s disease, an enteric infection in cattle and other ruminants, greatly afflicting the dairy industry worldwide. Once inside the cell, M. paratuberculosis is known to survive harsh microenvironments, especially those inside activated macrophages. To improve our understanding of M. paratuberculosis pathogenesis, we examined the phagosome maturation associated with transcriptional responses of M. paratuberculosis during macrophage infection. Monitoring cellular markers, only live M. paratuberculosis bacilli were able to prevent phagosome maturation and reduce its acidification. On the transcriptional level, over 300 of M. paratuberculosis genes were significantly, differentially regulated in both naïve and IFN-γ-activated macrophages. These genes include the sigma factor H (sigH) that was shown to be important during persistent infection in M. tuberculosis. Interestingly, a sigH-knockout mutant showed increased sensitivity to a sustained level of thiol-specific oxidative stress. Large-scale RNA sequence analysis revealed that a large number of genes belong to the sigH regulon, especially following diamide stress. Genes involved in oxidative stress and virulence were among the induced genes in the sigH regulon with a putative consensus sequence for SigH binding was recognized in a subset of these genes (N=30), suggesting direct regulation with SigH. Finally, mice infections showed a significant attenuation of the ∆sigH mutant compared to its parental strain suggesting a role for sigH in M. paratuberculosis virulence. Such analysis could identify potential targets for further testing as vaccine candidates against Johne’s disease.
2012-12-29 | GSE43182 | GEO
Project description:The numerous sigma factors present in Mycobacterium tuberculosis (MTB) are indicative of adaptability to different environmental conditions. In this report we describe the sigma factor B (sigB) regulon and the phenotypes of a MTB sigB mutant strain exposed to different stresses like SDS and Diamide. This experiment set compares expression profiles between H37Rv wild type and H37Rv sigB null mutant as well as under different stress conditions. Both H37Rv wild type and H37Rv sigB null mutants were treated with either 0.05% SDS or 5mM Diamide for 60 min and their expression profiles were compared with untreated wild type or mutant controls.
2009-06-23 | GSE15976 | GEO
Project description:The extracytoplasmic function sigma factor SigH is responsible for heat and oxidative stress response in a biotechnologically -important bacterium Corynebacterium glutamicum. Due to the hierarchical nature of the regulatory network, it has not been possible to fully determine the SigH regulon by previous transcriptome analyses. Here, we determined the direct genome-wide targets of SigH were determined by ChIP-chip analysis using a deletion mutant of rshA, encoding an anti-sigma factor of SigH. Seventy-five SigH-dependent promoters, including 39 new ones, were identified. Firstly, SigH-dependent heat induction was confirmed for several of the new targets, including two genes (ilvD and lipA) encoding Fe-S cluster containing enzymes. Internal SigH-dependent promoters were found in operon-like gene clusters involved in the pentose phosphate pathway, and riboflavin biosynthesis, and Zn uptake. Accordingly, deletion of rshA resulted in hyperproduction of riboflavin probably due to the coordinated upregulation of these genes. A SigH-dependent promoter was also found upstream of znuC1 in the znuA1C1B1 operon encoding an ABC-type transporter for Zn uptake. Overexpression of znuC1B1 by deletion of rshA and by an IPTG-inducible promoter and similarly affected expression of Zn-responsive genes, indicating that SigH-dependent upregulation of part of the operon potentiates Zn uptake. probably through Zn overload, indicating new physiological roles of SigH. Furthermore, reporter assays demonstrated that rshA in the sigH-rshA operon was heat-inducible under the control of an internal SigH-dependent promoters, identified upstream of rshA within the sigH-rshA operon, while the sigH promoter was independent of SigH, suggesting negative autoregulation of SigH activity. Finally, a SigH-dependent promoter identified and upstream of sigA encoding the primary sigma factor , wereas highly heat-inducible, but much weaker than the known SigA-dependent one.. The promoter upstream of sigH was independent of SigH but showed weak heat-shock response. The known SigA-dependent sigA promoter was much stronger than the SigH-dependent one. Taken together with the fact that SigH also regulates sigB encoding the primary-like sigma factor, Tthese findings uncovered a complicated regulatory network of the sigma factors.
2014-11-25 | GSE52039 | GEO
Project description:The extracytoplasmic function sigma factor SigH is responsible for heat and oxidative stress response in a biotechnologically -important bacterium Corynebacterium glutamicum. Due to the hierarchical nature of the regulatory network, it has not been possible to fully determine the SigH regulon by previous transcriptome analyses. Here, we determined the direct genome-wide targets of SigH were determined by ChIP-chip analysis using a deletion mutant of rshA, encoding an anti-sigma factor of SigH. Seventy-five SigH-dependent promoters, including 39 new ones, were identified. Firstly, SigH-dependent heat induction was confirmed for several of the new targets, including two genes (ilvD and lipA) encoding Fe-S cluster containing enzymes. Internal SigH-dependent promoters were found in operon-like gene clusters involved in the pentose phosphate pathway, and riboflavin biosynthesis, and Zn uptake. Accordingly, deletion of rshA resulted in hyperproduction of riboflavin probably due to the coordinated upregulation of these genes. A SigH-dependent promoter was also found upstream of znuC1 in the znuA1C1B1 operon encoding an ABC-type transporter for Zn uptake. Overexpression of znuC1B1 by deletion of rshA and by an IPTG-inducible promoter and similarly affected expression of Zn-responsive genes, indicating that SigH-dependent upregulation of part of the operon potentiates Zn uptake. probably through Zn overload, indicating new physiological roles of SigH. Furthermore, reporter assays demonstrated that rshA in the sigH-rshA operon was heat-inducible under the control of an internal SigH-dependent promoters, identified upstream of rshA within the sigH-rshA operon, while the sigH promoter was independent of SigH, suggesting negative autoregulation of SigH activity. Finally, a SigH-dependent promoter identified and upstream of sigA encoding the primary sigma factor , wereas highly heat-inducible, but much weaker than the known SigA-dependent one.. The promoter upstream of sigH was independent of SigH but showed weak heat-shock response. The known SigA-dependent sigA promoter was much stronger than the SigH-dependent one. Taken together with the fact that SigH also regulates sigB encoding the primary-like sigma factor, Tthese findings uncovered a complicated regulatory network of the sigma factors.
2014-11-25 | GSE52040 | GEO