Project description:The otsB2 gene encoding trehalose-6-phosphate phosphatase is essential for in vitro growth of Mycobacterium tuberculosis and required to establish an acute infection in mice. Essentiality of otsB2 is due to direct or indirect toxic effects associated with the substrate trehalose-6-phosphate that accumulates when OtsB2 gene expression is impaired. In order to gain insight into the molecular basis of trehalose-6-phosphate mediated toxic effects, whole genome transcriptome profiling was done using RNA-seq. A conditional otsB2 mutant of Mycobacterium tuberculosis was generated by inserting an anhydrotetracycline-inducible promoter cassette upstream of the otsB2 start codon,and the transcriptome profile of a fully induced mutant resembling the wildtype phenotype was compared to that of a partially silenced mutant under conditions where 30% residual growth relative to the fully induced mutant was observed.
Project description:New chemotherapeutics are urgently required to control the tuberculosis pandemic fueled by the emergence of multidrug- and extensively-drug-resistant Mycobacterium tuberculosis strains and the bacterium`s catastrophic alliance with HIV. Here we describe a novel trehalose-to-α-glucan pathway in M. tuberculosis comprising four enzymatic steps mediated by TreS, Pep2, GlgB, and GlgE, identified as an essential maltosyltransferase capable of utilizing maltose 1-phosphate. Using traditional and chemical reverse genetics, we show that GlgE inactivation causes rapid death of M. tuberculosis in vitro and in mice, through self-poisoning by maltose 1-phosphate accumulation driven by a self-amplifying feedback loop promoting pleiotropic phosphosugar-induced stress responses. Moreover, this α-glucan pathway exhibited a synthetic lethal interaction with the glucosyltransferase Rv3032 involved in biosynthesis of specialized α-glucan derivatives. The unique combination of gene essentiality within a synthetic lethal pathway validates GlgE as a new class of drug targets, revealing novel synergistic mechanisms to induce death in M. tuberculosis. Transcriptional profiling was performed to characterize the lethality induced by maltose 1-phosphate accumulation. Triplicate 10 mL cultures of the conditional lethal Mtb mutant strain H37Rv Delta treS Delta glgE (pMV361::treS) and of the vector control strain H37Rv Delta treS Delta glgE (pMV361) were grown in liquid culture to log-phase in the presence of 5 mM validamycin A (VA) to suppress M1P formation. Subsequently, cells were washed to remove the inhibitor; after 48 h of starvation for VA cultures were harvested. Keywords: tuberculosis, trehalose, compound treatment design, genetic modification design, and stimulus or stress design Three biological replicates with one dye-flip
Project description:New chemotherapeutics are urgently required to control the tuberculosis pandemic fueled by the emergence of multidrug- and extensively-drug-resistant Mycobacterium tuberculosis strains and the bacterium`s catastrophic alliance with HIV. Here we describe a novel trehalose-to-α-glucan pathway in M. tuberculosis comprising four enzymatic steps mediated by TreS, Pep2, GlgB, and GlgE, identified as an essential maltosyltransferase capable of utilizing maltose 1-phosphate. Using traditional and chemical reverse genetics, we show that GlgE inactivation causes rapid death of M. tuberculosis in vitro and in mice, through self-poisoning by maltose 1-phosphate accumulation driven by a self-amplifying feedback loop promoting pleiotropic phosphosugar-induced stress responses. Moreover, this α-glucan pathway exhibited a synthetic lethal interaction with the glucosyltransferase Rv3032 involved in biosynthesis of specialized α-glucan derivatives. The unique combination of gene essentiality within a synthetic lethal pathway validates GlgE as a new class of drug targets, revealing novel synergistic mechanisms to induce death in M. tuberculosis. Transcriptional profiling was performed to characterize the lethality induced by maltose 1-phosphate accumulation. Triplicate 10 mL cultures of the conditional lethal Mtb mutant strain H37Rv Delta treS Delta glgE (pMV361::treS) and of the vector control strain H37Rv Delta treS Delta glgE (pMV361) were grown in liquid culture to log-phase in the presence of 5 mM validamycin A (VA) to suppress M1P formation. Subsequently, cells were washed to remove the inhibitor; after 48 h of starvation for VA cultures were harvested. Keywords: tuberculosis, trehalose, compound treatment design, genetic modification design, and stimulus or stress design
Project description:These data represent the global gene expression profile of Mycobacterium tuberculosis after 24 hrs and 72 hrs of inorganic phosphate starvation. Differentially regulated genes appear to include those encoding proteins involved in adaptation to phosphate starvation, namely those involved in phosphate regulation and phosphate assimilation, as well as those involved in the stringent response.
Project description:MmpL3 is an inner membrane transporter of Mycobacterium tuberculosis responsible for the export of trehalose momomycolate, a precursor of the mycobacterial outer membrane component trehalose dimycolate (TDM), as well as mycolic acids bound to arabinogalactan. MmpL3 represents an emerging target for tuberculosis therapy. In this paper, we describe the construction and characterization of an mmpL3 knockdown strain of M. tuberculosis. Downregulation of mmpL3 led to a stop in bacterial division and rapid cell death, preceded by the accumulation of TDM precursors. MmpL3 was also shown to be essential for growth in monocyte-derived human macrophages. Using RNA-seq we also found that MmpL3 depletion caused up-regulation of 47 genes and down-regulation of 23 genes (at least 3-fold change and false discovery rate ≤ 1%). Several genes related to osmoprotection and metal homeostasis were induced, while several genes related to energy production and mycolic acids biosynthesis were repressed suggesting that inability to synthesize a correct outer membrane leads to changes in cellular permeability and a metabolic shiftdown.
Project description:Comparison of gene expression profile of the whiB4 mutant strain of Mycobacterium tuberculosis with the wild type Mycobacterium tuberculosis H37RV Mtb WhiB4 mutant mRNA was compared with the mRNA of wtMtb H37RV under aerobic conditons
Project description:This SuperSeries is composed of the following subset Series: GSE36341: mRNA degradation in Mycobacterium tuberculosis under aerobic conditions GSE36342: mRNA degradation in Mycobacterium smegmatis under aerobic conditions GSE36343: mRNA degradation in Mycobacterium tuberculosis during cold and hypoxic stress GSE36344: mRNA degradation in Mycobacterium tuberculosis with DosR ectopically induced Refer to individual Series
Project description:Transcriptional profile of Mycobacterium tuberculosis in in vitro acid-nitrosative multistress, comparing untreated control cells and bacteria under multi-stress.
Project description:This SuperSeries is composed of the following subset Series: GSE6209: The global transcriptional profile of Mycobacterium tuberculosis during human macrophages infection GSE7962: Sigma factor E of Mycobacterium tuberculosis controls the expression of bacterial components that modulate macrophages Keywords: SuperSeries Refer to individual Series