WhiB6 is required for the secretion-dependent regulation of ESX-1 substrates in pathogenic mycobacteria
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ABSTRACT:
ORGANISM(S): Mycobacterium tuberculosis H37Rv Mycobacterium marinum E11 Mycobacterium marinum M
PROVIDER: GSE124341 | GEO | 2018/12/25
REPOSITORIES: GEO
Similar Datasets
Project description:WhiB6 is required for the secretion-dependent regulation of ESX-1 substrates in pathogenic mycobacteria
| PRJNA511673 | ENA
Project description:WhiB6 is a transcription factor that regulates expression of genes encoding ESX-1 substrates. We found that in the absence of the genes encoding conserved membrane components of the ESX-1 system, the expression of the whiB6 gene and genes encoding ESX-1 substrates were reduced.
2017-11-27 | GSE99632 | GEO
Project description:The mycobacterial type VII secretion system ESX-1 is responsible for the secretion of a number of proteins that play important roles during host infection. The regulation of the expression of secreted proteins is often essential to establish successful infection. Using transcriptome sequencing, we found that the abrogation of ESX-1 function in Mycobacterium marinum leads to a pronounced increase in gene expression levels of the espA operon during the infection of macrophages. In addition, the disruption of ESX-1-mediated protein secretion also leads to a specific down-regulation of the ESX-1 substrates, but not of the structural components of this system, during growth in culture medium. This effect is observed in both M. marinum and M. tuberculosis. We established that down-regulation of ESX-1 substrates is the result of a regulatory process that is influenced by the putative transcriptional regulator whib6, which is located adjacent to the esx-1 locus. In addition, the overexpression of the ESX-1-associated PE35/PPE68 protein pair resulted in a significantly increased secretion of the ESX-1 substrate EsxA, demonstrating a functional link between these proteins. Taken together, these data show that WhiB6 is required for the secretion-dependent regulation of ESX-1 substrates and that ESX-1 substrates are regulated independently from the structural components, both during infection and as a result of active secretion.
| S-EPMC6343904 | biostudies-literature
Project description:The ESX-1, type VII, secretion system represents the major virulence determinant of Mycobacterium tuberculosis. The ESX-1 cluster comprises approximately twenty genes and encodes a specialized secretion apparatus, which releases effectors into the extracellular milieu. The goal of this study is to understand the role of EspL. We show that EspL, a protein of 115 amino acids, is essential for mediating ESX-1-dependent virulence and for stabilization of EspE, EspF and EspH protein levels. Indeed, an espL knock-out mutant was unable to replicate intracellularly, secrete ESX-1 substrates or stimulate innate cytokine production. Moreover, loss of EspL also leads to downregulation in M. tuberculosis of WhiB6, a redox-sensitive transcriptional activator of ESX-1 genes.
2018-12-07 | GSE118994 | GEO
Project description:The pathogen Mycobacterium tuberculosis employs a range of ESX-1 substrates to manipulate the host and build a successful infection. Although the importance of ESX-1 secretion in virulence is well established, the characterization of its individual components and the role of individual substrates is far from complete. Here, we describe the functional characterization of the accessory ESX-1 proteins EccA1, EspG1 and EspH, i.e. proteins that are not present in all five ESX system of mycobacteria. Proteomic analysis revealed that EspG1 is crucial for ESX-1 secretion, since all detectable ESX-1 substrates were absent from the cell surface and culture supernatant in an espG1 mutant. Deletion of eccA1 resulted in minor secretion defects, but interestingly, the severity of these secretion defects was dependent on the culture conditions. Finally, espH deletion showed a partial secretion defect, only secretion of EspE, EspF and EsxA/EsxB was blocked.
2018-08-02 | PXD008905 | Pride
Project description:The dedicated secretion system ESX-1 of Mycobacterium tuberculosis encoded by the extended RD1 region (extRD1) assures export of the ESAT-6 protein and its partner, the 10 kDa culture filtrate protein CFP-10, and is missing from the vaccine strains M.bovis BCG and M.microti. Here, we systematically investigated the involvement of each individual ESX-1 gene in the secretion of both antigens, specific immunogenicity and virulence. ESX-1-complemented BCG and M.microti strains were more efficiently engulfed by bone marrow derived macrophages than controls and this may account for the enhanced in vivo growth of ESX-1 carrying strains. Inactivation of gene pe35 (Rv3872) impaired expression of CFP-10 and ESAT-6 suggesting a role in regulation. Genes Rv3868, Rv3869, Rv3870, Rv3871 and Rv3877 encoding an ATP-dependent chaperone and translocon were essential for secretion of ESAT-6 and CFP-10 in contrast to ppe68 (Rv3873) and Rv3876, whose inactivation did not impair secretion of ESAT-6. A strict correlation was found between ESAT-6 export and the generation of ESAT-6 specific T-cell responses in mice. Furthermore, ESAT-6 secretion and specific immunogenicity were almost always correlated with enhanced virulence in the SCID mouse model. Only loss of Rv3865 and part of Rv3866 did not affect ESAT-6 secretion or immunogenicity, but led to attenuation. This suggests that Rv3865/66 represent a new virulence factor that is independent from ESAT-6 secretion. This study has allowed us to identify new aspects of the extRD1 region of M.tuberculosis and to explore its role in the pathogenesis of tuberculosis. Data is also available from http://bugs.sgul.ac.uk/E-BUGS-31
2007-01-30 | E-BUGS-31 | biostudies-arrayexpress
Project description:Pathogenic mycobacteria contain up to five type VII secretion (T7S) systems, ESX-1 to ESX-5, which have central roles in virulence and viability. One of the conserved components of these systems, the serine protease mycosin (MycP), has been shown to be essential for secretion by ESX-1 and ESX-5. However, here we show that protease activity of MycP1 and MycP5 of M. marinum is not essential for ESX-1 and ESX-5 dependent secretion, respectively. This indicates that MycP has a second, so far unknown, function that is essential for T7S. To investigate whether this second role is related to proper functioning of the T7S membrane core complex, we first verified that the ESX-1 membrane complex is of similar composition and size as the previously analyzed ESX-5 complex and that MycP1 and MycP5 are not an integral part of the respective core complex. In contrast, we could not detect ESX-1 and ESX-5 complexes under mycP1 and mycP5 knockout conditions, respectively. Interestingly, the ESX-5 complex could be detected at wild-type levels in the absence of MycP5, when membranes were subjected to crosslinking before detergent solubilization, suggesting that MycP is involved in complex stabilization. Based on our findings we hypothesize that mycosins loosely associate with their respective membrane complex, which is crucial for the full integrity and functioning of the secretion machinery.
2016-10-11 | PXD003766 | Pride
Project description:Mycobacteria possess different type VII secretion (T7S) systems to secrete proteins across their unusual cell envelope. One of these systems, ESX-5, is only present in slow-growing mycobacteria and responsible for the secretion of multiple substrates. However, the role of ESX-5 substrates in growth and/or virulence is largely unknown. In this study, we show that esx-5 is essential for growth of both Mycobacterium marinum and Mycobacterium bovis. Remarkably, this essentiality can be rescued by increasing the permeability of the outer membrane, either by altering its lipid composition or by the introduction of the heterologous porin MspA. Mutagenesis of the first nucleotide-binding domain of the membrane ATPase EccC5 prevented both ESX-5-dependent secretion and bacterial growth, but did not affect ESX-5 complex assembly. This suggests that the rescuing effect is not due to pores formed by the ESX-5 membrane complex, but caused by ESX-5 activity. Subsequent proteomic analysis to identify crucial ESX-5 substrates confirmed that all detectable PE and PPE proteins in the cell surface and cell envelope fractions were routed through ESX-5. Additionally, saturated transposon-directed insertion-site sequencing (TraDIS) was applied to both wild-type M. marinum cells and cells expressing mspA to identify genes that are not essential anymore in the presence of MspA. This analysis confirmed the importance of esx-5, but we could not identify essential ESX-5 substrates, indicating that multiple of these substrates are together responsible for the essentiality. Finally, examination of phenotypes on defined carbon sources revealed that an esx-5 mutant is strongly impaired in the uptake and utilization of hydrophobic carbon sources. Based on these data, we propose a model in which the ESX-5 system is responsible for the transport of cell envelope proteins that are required for nutrient uptake. These proteins might in this way compensate for the lack of MspA-like porins in slow-growing mycobacteria.
| S-EPMC4418733 | biostudies-literature
Project description:The ESX-1, type VII, secretion system represents the major virulence determinant of Mycobacterium tuberculosis, one of the most successful intracellular pathogens. Here, by combining genetic and high-throughput approaches, we show that EspL, a protein of 115 amino acids, is essential for mediating ESX-1-dependent virulence and for stabilization of EspE, EspF and EspH protein levels. Indeed, an espL knock-out mutant was unable to replicate intracellularly, secrete ESX-1 substrates or stimulate innate cytokine production. Moreover, proteomic studies detected greatly reduced amounts of EspE, EspF and EspH in the espL mutant as compared to the wild type strain, suggesting a role for EspL as a chaperone. The latter conclusion was further supported by discovering that EspL interacts with EspD, which was previously demonstrated to stabilize the ESX-1 substrates and effector proteins, EspA and EspC. Moreover, loss of EspL also leads to downregulation in M. tuberculosis of WhiB6, a redox-sensitive transcriptional activator of ESX-1 genes. Overall, our data highlight the importance of a so-far overlooked, though conserved, component of the ESX-1 secretion system and begin to delineate the role played by EspE, EspF and EspH in virulence and host-pathogen interaction.
2018-12-10 | PXD010929 | Pride
Project description:Mycobacterium tuberculosis, a pathogen of global importance, utilizes the ESX-1 protein secretion system to export virulence factors that disarm host macrophages. Although this secretory pathway is critical for virulence, how ESX-1 is regulated is completely unknown. Here we show that EspR (Rv3849) is a key regulator of ESX-1. EspR activates transcription of an operon that includes three ESX-1 components, Rv3616c-Rv3614c, whose expression in turn promotes secretion of ESX-1 substrates. Keywords: Strain comparison
2008-08-08 | GSE12381 | GEO