Project description:Mycobacterium tuberculosis (Mtb) is well adapted to survive in macrophages and usually subverts the bactericidal mechanisms of these professional phagocytes. The adaptation of Mtb to the intracellular life depends on its ability to regulate the expression of its genes. Among the most important bacterial transcription activators are the sigma factors that bind to the RNA polymerase and give it promotor specificity. Sigma factor E (SigE) controls the expression of genes that are essential for Mtb virulence. Analysis of the macrophage transcriptional response indicated that proteins encoded by the sigE regulon are involved in the modulation of the macrophage inflammatory response. Keywords: Comparison of responses to infections
Project description:Mycobacterium tuberculosis (Mtb) is well adapted to survive in macrophages and usually subverts the bactericidal mechanisms of these professional phagocytes. The adaptation of Mtb to the intracellular life depends on its ability to regulate the expression of its genes. Among the most important bacterial transcription activators are the sigma factors that bind to the RNA polymerase and give it promotor specificity. Sigma factor E (SigE) controls the expression of genes that are essential for Mtb virulence. Analysis of the macrophage transcriptional response indicated that proteins encoded by the sigE regulon are involved in the modulation of the macrophage inflammatory response. Keywords: Comparison of responses to infections
Project description:Mycobacterium tuberculosis (Mtb) is well adapted to survive in macrophages and usually subverts the bactericidal mechanisms of these professional phagocytes. The adaptation of Mtb to the intracellular life depends on its ability to regulate the expression of its genes. Among the most important bacterial transcription activators are the sigma factors that bind to the RNA polymerase and give it promotor specificity. Sigma factor E (SigE) controls the expression of genes that are essential for Mtb virulence. Analysis of the macrophage transcriptional response indicated that proteins encoded by the sigE regulon are involved in the modulation of the macrophage inflammatory response. We compared the global gene expression of mouse bone marrow macrofages infected with H37Rv and SigE to the gene expression profile of the uninfected macrophages.
Project description:Mycobacterium tuberculosis (Mtb) is well adapted to survive in macrophages and usually subverts the bactericidal mechanisms of these professional phagocytes. The adaptation of Mtb to the intracellular life depends on its ability to regulate the expression of its genes. Among the most important bacterial transcription activators are the sigma factors that bind to the RNA polymerase and give it promotor specificity. Sigma factor E (SigE) controls the expression of genes that are essential for Mtb virulence. Analysis of the macrophage transcriptional response indicated that proteins encoded by the sigE regulon are involved in the modulation of the macrophage inflammatory response. We compared the global gene expression of THP1 macrophages infected with H37Rv and SigE to the gene expression profile of uninfected macrophages.
Project description:Sigma factor E (SigE) controls the expression of genes that are essential for Mtb virulence. In this work, we have identified the SigE regulon during infection of macrophages Our results indicate that SigE regulates the expression of genes involved in the maintenance of Mtb cell envelope integrity and function (i.e., detoxification and secretion). Keywords: strains comparison We compared the global gene expression of the H37Rv strain and the sigE mutant strain of Mtb in different conditions: growing exponentially in liquid media; after 2h of incubation in RPMI; or after 24 hours of infection of human macrophage-like THP-1 cells.
Project description:During lung infection Mycobacterium tuberculosis (Mtb) resides in macrophages and subverts the bactericidal mechanisms of these professional phagocytes. In this work we have analyzed by DNA microarray technique the global transcription profile of Mtb infecting primary human macrophages in order to identify putative bacterial pathogenic factors that can be relevant for the intracellular survival of Mtb. Keywords: time course We compared the global gene expression of the H37Rv strain of Mtb after 4 hours and 24 hours of infection of human macrophage-like THP-1 cells with the gene expression profile of the strain growing exponentially in broth cultures.
Project description:We used DNA microarrays to define the M. tuberculosis whiB5 regulon and to study the variation of the global transcription profile in response of its induction. For this purpose we constructed a M. tuberculosis strain in which whiB5 was transcribed from an pristinamycin-inducible promoter and its transcriptional profile was compared on DNA microarray with the transcriptional profile of its control strain (empty vector-containing clone). WhiB5 induction for 15’ resulted in the induction of 26 genes, while induction for 3 h resulted in the induction of 58 genes. Interestingly, all of the 26 genes induced after 15 minutes of incubation with pristinamycin were still induced after 3 h of incubation. No repressed genes were identified. Among the induced genes we found the alternative sigma factor SigM and at least 12 genes previously shown to be regulated by this sigma factor, including those encoding the ESX-4 type VII secretion system. Interestingly, also the genes encoding ESX-2 type VII secretion system were strongly induced together with an operon probably involved in hydrogen metabolism in anaerobiosis. 10 representative genes were chosen from the microarray experiments and their expression was measured by quantitative RT-PCR using sigA as invariant internal control. In support to the gene expression profiling data, the mRNA levels of all selected genes was clearly higher in the whiB5 mutant strain relative to control. We compared the global gene expression of the whiB5 overexpressing strain and the control strain of Mtb in different conditions: after 15 min of induction or after 3 hours of induction. Hybridizations were performed using RNA extracted from three different biological samples. Each sample was hybridized twice through swap labeling of the respective cDNAs.
Project description:Mycobacterium tuberculosis (Mtb) displayed cording phenotypes during intracellular infection. RNA-Seq was used to identify transcriptional programmes expressed by hLEC that actviates pathways relating to cellular pro-survival and cyosolic surveillance of intracellular Mtb. Mtb cording was found to be a mechanism to evade xenophagy in the cytosol of endothelial cells.
Project description:The host restricts Mycobacterium tuberculosis (Mtb) access of transition metal ions to inhibit its growth. Cu is essential for the survival of Mtb, but Cu excess is toxic. During co-evolution, Mtb has developed various mechanisms to maintain copper homeostasis. In this report, we firstly found Mtb Rv0102 encoded membrane protein is critical for Mycobacterium Cu uptake. The intracellular Cu level of M. smegmatis (Ms) Rv0102 homolog MSMEG_4702 knockout strain decreased threefold than the wild type, the deletion mutant was more tolerant to higher Cu level. This indicates that Rv0102 is significant for Cu homeostasis and resistance to Cu toxicity. Knocking out the homologous gene MMAR_0267 in M. marinum (Mm) also enhanced its virulence in zebrafish and improved its survival within macrophages. In THP-1 cells infected with Mm, Mm MMAR_0267 deletion mutants’ intracellular survival increased fourfolds and accompanied by less cell apoptosis. Cu deficiency down-regulates the transcription of the M. marinum virulence factor CFP-10, dampening the STING cytosolic signaling in macrophages, fewer IFN-β and less cell apoptosis. These results suggest that Cu is an important factor in inducing cell apoptosis. In summary, mycobacteria can effectively counteract the host's early key nutritional immune mechanisms by regulating copper metabolism, to increase its virulence.
Project description:Sigma factor E (SigE) controls the expression of genes that are essential for Mtb virulence. In this work, we have identified the SigE regulon during infection of macrophages Our results indicate that SigE regulates the expression of genes involved in the maintenance of Mtb cell envelope integrity and function (i.e., detoxification and secretion). Keywords: strains comparison