Determining the M. smegmatis DosR regulon
Ontology highlight
ABSTRACT:
ORGANISM(S): Mycolicibacterium smegmatis
PROVIDER: GSE56083 | GEO | 2014/07/10
SECONDARY ACCESSION(S): PRJNA242381
REPOSITORIES: GEO
Similar Datasets
Project description:DosR is the regulator of a two-component system in mycobacteria that senses oxygen concentration and the redox state of the cells. To determine the DosR regulon, the transcriptomes of M. smegmatis mc2155 and the M-NM-^TdosR cells were compared by microarray at 10 hours following induction of oxygen-limitation in serum vials. 4 biological replicates incl. 2 dye swaps. 3 technical replicates per array
2014-07-10 | E-GEOD-56083 | biostudies-arrayexpress
Project description:The DosR regulon in Mycobacterium tuberculosis is involved in respiration-limiting conditions and its induction is controlled by two histidine kinases, DosS and DosT. Recent experimental evidence indicates DosS senses either molecular oxygen or a redox change. This report demonstrates that DosS responds to a reduced electron transport system (ETS), although this does not rule out a role for oxygen in silencing signaling. Under aerobic conditions induction of the DosR regulon by DosS but not DosT was observed after the addition of ascorbate, a powerful cytochrome c reductant, demonstrating DosS responds to a redox signal even in the presence of high oxygen tension. During hypoxic conditions regulon induction was attenuated by treatment with compounds that occluded electron flow into the menaquinone pool or decreased the size of the menaquinone pool itself. Increased regulon expression during hypoxia was observed when exogenous menaquinone was added, demonstrating the menaquinone pool is a limiting factor in regulon induction. Taken together these data indicate that a reduced menaquinone pool directly or indirectly triggers induction of the DosR regulon via DosS. Biochemical analysis of menaquinones upon entry into hypoxic/anaerobic conditions demonstrated the disappearance of the unsaturated species and low-level maintenance of the mono-saturated menaquinone. Relative to the unsaturated form, an analog of the saturated form is better able to induce signaling via DosS, rescue inhibition of menaquinone synthesis, and is less toxic. The menaquinone pool is central to the ETS and therefore provides a mechanistic link between the respiratory state of the bacilli and DosS signaling. Aerobically growing logarithmic phase DosS and DosT mutant strains were analyzed after treatment with the cytochrome c reductant ascorbate to examine the effect on DosR signaling caused by reducing the electron transport system. Experiments were repeated in triplicate (dosT mutant) or duplicate (dosS mutant).
2010-05-22 | E-GEOD-21963 | biostudies-arrayexpress
Project description:The DosR regulon in Mycobacterium tuberculosis is involved in respiration-limiting conditions and its induction is controlled by two histidine kinases, DosS and DosT. Recent experimental evidence indicates DosS senses either molecular oxygen or a redox change. This report demonstrates that DosS responds to a reduced electron transport system (ETS), although this does not rule out a role for oxygen in silencing signaling. Under aerobic conditions induction of the DosR regulon by DosS but not DosT was observed after the addition of ascorbate, a powerful cytochrome c reductant, demonstrating DosS responds to a redox signal even in the presence of high oxygen tension. During hypoxic conditions regulon induction was attenuated by treatment with compounds that occluded electron flow into the menaquinone pool or decreased the size of the menaquinone pool itself. Increased regulon expression during hypoxia was observed when exogenous menaquinone was added, demonstrating the menaquinone pool is a limiting factor in regulon induction. Taken together these data indicate that a reduced menaquinone pool directly or indirectly triggers induction of the DosR regulon via DosS. Biochemical analysis of menaquinones upon entry into hypoxic/anaerobic conditions demonstrated the disappearance of the unsaturated species and low-level maintenance of the mono-saturated menaquinone. Relative to the unsaturated form, an analog of the saturated form is better able to induce signaling via DosS, rescue inhibition of menaquinone synthesis, and is less toxic. The menaquinone pool is central to the ETS and therefore provides a mechanistic link between the respiratory state of the bacilli and DosS signaling.
2010-05-22 | GSE21963 | GEO
Project description:In this report we demonstrated that under aerobic conditions, Mycobacterium bovis BCG expressing an hsp60-driven second copy of the hypoxia-related transcriptional regulator DosR increased 2-fold or greater the expression of 38 out of the 48 genes belonging to the DosR regulon, including the latency antigens Rv1733c, Rv2029, Rv2627, and Rv2628. Expression of DosR under these conditions slightly delayed in vitro growth, but did not promote a non-replicating state as opposed to microaerobic and hypoxic adaptation. Our results suggest BCG producing DosR can be cultured under standard in vitro conditions, allowing evaluation of this strain as a latency-specific vaccine candidate.
2010-05-21 | GSE21932 | GEO
Project description:In Mycobacterium tuberculosis, the sensor kinases DosT and DosS activate the transcriptional regulator DosR, resulting in the induction of the DosR regulon, important for anaerobic survival and perhaps latent infection. The individual and collective roles of these sensors has been postulated biochemically, but their roles have remained unclear in vivo. This work demonstrates distinct and additive roles for each sensor during anaerobic dormancy. Both sensors are necessary for wild type levels of DosR regulon induction, and concomitantly, full induction of the regulon is required for wild type anaerobic survival. In the anaerobic model, DosT plays an early role, responding to hypoxia. DosT then induces the regulon and with it DosS, which sustains and further induces the regulon. DosT then loses its functionality as oxygen becomes limited, and DosS alone maintains induction of the genes from that point forward. Thus, M. tuberculosis has evolved a system whereby it responds to hypoxic conditions in a stepwise fashion as it enters an anaerobic state.
2009-06-26 | GSE16811 | GEO
Project description:In this report we demonstrated that under aerobic conditions, Mycobacterium bovis BCG expressing an hsp60-driven second copy of the hypoxia-related transcriptional regulator DosR increased 2-fold or greater the expression of 38 out of the 48 genes belonging to the DosR regulon, including the latency antigens Rv1733c, Rv2029, Rv2627, and Rv2628. Expression of DosR under these conditions slightly delayed in vitro growth, but did not promote a non-replicating state as opposed to microaerobic and hypoxic adaptation. Our results suggest BCG producing DosR can be cultured under standard in vitro conditions, allowing evaluation of this strain as a latency-specific vaccine candidate. Set of arrays that are part of repeated experiments
2010-05-20 | E-GEOD-21932 | biostudies-arrayexpress
Project description:In Mycobacterium tuberculosis, the sensor kinases DosT and DosS activate the transcriptional regulator DosR, resulting in the induction of the DosR regulon, important for anaerobic survival and perhaps latent infection. The individual and collective roles of these sensors has been postulated biochemically, but their roles have remained unclear in vivo. This work demonstrates distinct and additive roles for each sensor during anaerobic dormancy. Both sensors are necessary for wild type levels of DosR regulon induction, and concomitantly, full induction of the regulon is required for wild type anaerobic survival. In the anaerobic model, DosT plays an early role, responding to hypoxia. DosT then induces the regulon and with it DosS, which sustains and further induces the regulon. DosT then loses its functionality as oxygen becomes limited, and DosS alone maintains induction of the genes from that point forward. Thus, M. tuberculosis has evolved a system whereby it responds to hypoxic conditions in a stepwise fashion as it enters an anaerobic state. Various DosS and DosT mutant strains were analyzed against wild type (reference strain H37Rv, identical conditions as mutant) under various conditions: day 6 in an anaerobic dormancy model, 4 or 24 hours in a GasPak model, or log phase with the addition of a nitric oxide donor. Experiments were repeated in triplicate or quadruplicate.
2009-06-26 | E-GEOD-16811 | biostudies-arrayexpress
Project description:Background: Conflicting results have been reported about the role of the two-component sensor and transcriptional regulator DosS/DosR, controlling the expression of the dormancy DosR regulon, for in vivo virulence of M. tuberculosis. Here, we have used a new approach to further analyze the relevance of the dosRS system, by driving DosR (Rv3133c) expression under the control of a constitutive promoter (phsp60). Methodology/Principal Findings: M. tuberculosis H37Rv constitutively expressing the transcriptional regulator DosR (Mtb::DosR) was compared to wild type M. tuberculosis (Mtb+/+) for in vitro growth kinetics and expression of the target genes of the DosR dormancy regulon, for in vivo virulence and for immunogenicity in mice. Under aerobic conditions, hsp60-driven DosR induced the expression of 28 out of 39 tested DosR regulon genes. In vitro growth characteristics were comparable for both strains, but Mtb::DosR showed an attenuated in vivo phenotype in immunocompetent mice, as indicated by reduced bacterial replication, reduced pulmonary immunopathology, reduced cachexia and significantly prolonged survival time as compared Mtb+/+. In immunodeficient SCID mice, Mtb::DosR was fully virulent. RT-qPCR analysis revealed a strong and comparable pulmonary TNF-?? and IL-23 expression following intratracheal infection, whereas IL-12 and IL-17 expression was slightly higher with wild type Mtb+/+. Finally, mice persistently infected with Mtb::DosR for 8 months showed five to tenfold higher lung IFN-?? responses against ten of the 48 DosR regulon encoded antigens (Rv1733c, Rv1734, Rv1738, Rv1996, Rv1997, Rv2029c, Rv2623, Rv2627c, Rv2628 and Rv3127) than mice actively infected with Mtb+/+. In spleen however, DosR regulon encoded antigen specific IFN-?? responses were similar in both groups. Conclusions/Significance. Collectively, these results suggest that increased DosR regulon encoded antigen specific pulmonary T cell responses are responsible for the attenuated phenotype of Mtb::DosR and that infection with Mtb::DosR could be used as a new animal model for studying key aspects of latent tuberculosis.
2012-06-13 | GSE19838 | GEO
Project description:Background: Conflicting results have been reported about the role of the two-component sensor and transcriptional regulator DosS/DosR, controlling the expression of the dormancy DosR regulon, for in vivo virulence of M. tuberculosis. Here, we have used a new approach to further analyze the relevance of the dosRS system, by driving DosR (Rv3133c) expression under the control of a constitutive promoter (phsp60). Methodology/Principal Findings: M. tuberculosis H37Rv constitutively expressing the transcriptional regulator DosR (Mtb::DosR) was compared to wild type M. tuberculosis (Mtb+/+) for in vitro growth kinetics and expression of the target genes of the DosR dormancy regulon, for in vivo virulence and for immunogenicity in mice. Under aerobic conditions, hsp60-driven DosR induced the expression of 28 out of 39 tested DosR regulon genes. In vitro growth characteristics were comparable for both strains, but Mtb::DosR showed an attenuated in vivo phenotype in immunocompetent mice, as indicated by reduced bacterial replication, reduced pulmonary immunopathology, reduced cachexia and significantly prolonged survival time as compared Mtb+/+. In immunodeficient SCID mice, Mtb::DosR was fully virulent. RT-qPCR analysis revealed a strong and comparable pulmonary TNF-?? and IL-23 expression following intratracheal infection, whereas IL-12 and IL-17 expression was slightly higher with wild type Mtb+/+. Finally, mice persistently infected with Mtb::DosR for 8 months showed five to tenfold higher lung IFN-?? responses against ten of the 48 DosR regulon encoded antigens (Rv1733c, Rv1734, Rv1738, Rv1996, Rv1997, Rv2029c, Rv2623, Rv2627c, Rv2628 and Rv3127) than mice actively infected with Mtb+/+. In spleen however, DosR regulon encoded antigen specific IFN-?? responses were similar in both groups. Conclusions/Significance. Collectively, these results suggest that increased DosR regulon encoded antigen specific pulmonary T cell responses are responsible for the attenuated phenotype of Mtb::DosR and that infection with Mtb::DosR could be used as a new animal model for studying key aspects of latent tuberculosis. Set of arrays that are part of repeated experiments
2012-06-12 | E-GEOD-19838 | biostudies-arrayexpress
Project description:Tuberculosis caused by Mycobacterium tuberculosis (Mtb) infection remains a huge global public health problem. One striking characteristic of Mtb is its ability to adapt to hypoxia, and thus ensuing transition to dormant state for persistent infection, but how the hypoxia responses of Mtb is regulated remains largely unknown. Here, we performed a quantitative acetylome analysis to compare the acetylation profile of Mtb under aeration and hypoxia, and showed that 377 acetylation sites in 269 proteins of Mtb were significantly change under hypoxia. Especially, deacetylation of Dormancy Survival Regulator (DosR) at K182 promoted the hypoxia response of Mtb and enhanced transcription of DosR-targeted genes. Mechanistically, recombinant DosRK182R protein demonstrated enhanced DNA-binding activity in comparison with DosRK182Q protein. Moreover, Rv0998 was identified as an acetyltransferase that mediates the acetylation of DosR at K182. Deletion of Rv0998 also promoted the adaption of Mtb to hypoxia and transcription of DosR-targeted genes. Mice infected with Mtb strain containing acetylation-defective DosRK182R or lacking Rv0998 had much lower bacterial counts, and less severe histopathological impairments compared with those infected with the wild-type strain. Our findings suggest that hypoxia induces the deacetylation of DosR, which in turn increases its DNA binding ability to promote the transcription of target genes, allowing Mtbto transit to dormancy under hypoxia.
2018-10-22 | PXD008587 | Pride