Project description:Tuberculosis (2004) 84, 188196 (www.elsevierhealth.com/journals/tube),Comparative expression studies of a complex phenotype: cord formation in Mycobacterium tuberculosis,Qian Gao, Katharine Kripke, Zuhre Arinc, Martin Voskuil, Peter Small
Project description:Identification of changes in microRNA expression, remodelling of relationships between microRNA and mRNA expression levels, and genetic polymorphisms associated with inter-individual variation in the dendritic cell immune response to Mycobacterium tuberculosis infection. We characterised genome-wide changes in microRNA expression, and of the broader miRNA-mdeiated regulatory system, in response to Mycobacterium tuberculosis (MTB) infection, and assessed the extent to which this response is under genetic control. To do so, we profiled microRNA expression levels in primary dendritic cells from 65 individuals before and after infection with MTB for 18 hours.
Project description:The PhoPR two-component system is essential for virulence in Mycobacterium tuberculosis where it controls expression of approximately 2% of the genes, including those for the ESX-1 secretion apparatus, a major virulence determinant. Mutations in phoP lead to compromised production of pathogen-specific cell wall components and attenuation both ex vivo and in vivo. Using antibodies against the native protein in ChIP-seq experiments (chromatin immunoprecipitation followed by high-throughput sequencing) we demonstrated that PhoP binds to at least 35 loci on the M. tuberculosis genome. The PhoP regulon comprises several transcriptional regulators as well as genes for polyketide synthases and PE/PPE proteins. Integration of ChIP-seq results with high-resolution transcriptomic analysis (RNA-seq) revealed that PhoP controls 30 genes directly, whilst regulatory cascades are responsible for signal amplification and downstream effects. The most prominent site of PhoP regulation was located in the intergenic region between rv2395 and PE_PGRS41, where the mcr7 gene codes for a small non-coding RNA (ncRNA). Northern blot experiments confirmed the absence of Mcr7 in the M. tuberculosis phoP mutant as well as low-level expression of the ncRNA in M. tuberculosis complex members other than M. tuberculosis. By means of genetic and proteomic analyses we demonstrated that Mcr7 modulates translation of the tatC mRNA thereby impacting the activity of the Twin Arginine Translocation (Tat) protein secretion apparatus. As a result, secretion of the immunodominant Ag85 complex and the beta-lactamase BlaC is affected, among others. Mcr7, the first ncRNA of M. tuberculosis whose function has been established, therefore represents a missing link between the PhoPR two-component system and the downstream functions necessary for successful infection of the host. ChiP-Seq: M. tuberculosis H37Rv (GC1237) cultures grown in vitro to exponential phase. Two wild type samples plus one isogenic phoP mutant as control
Project description:Transcriptional profiling of SirR and manganese regulated expression of genes in Mycobacterium tuberculosis strains comparing high manganese vs. low manganese in Rv (wild type Mycobacterium tuberculosis) and ST70 (mntR mutant strain of Mycobacterium tuberculosis) Overall design: Two strains each with two conditions experiment, Rv (Mycobacterium tuberculosis wild type strain) high manganese vs. low manganese and ST70 (mntR mutant strain of Mycobacterium tuberculosis) high manganese vs. low manganese. Number of biological replicates is 3 for each condition for each strain.
Project description:Transcriptional profiling of SirR and manganese regulated expression of genes in Mycobacterium tuberculosis strains comparing high manganese vs. low manganese in Rv (wild type Mycobacterium tuberculosis) and ST70 (mntR mutant strain of Mycobacterium tuberculosis) Two strains each with two conditions experiment, Rv (Mycobacterium tuberculosis wild type strain) high manganese vs. low manganese and ST70 (mntR mutant strain of Mycobacterium tuberculosis) high manganese vs. low manganese. Number of biological replicates is 3 for each condition for each strain.
Project description:The innate immune system provides the first response to pathogen infection and orchestrates the activation of the adaptive immune system. Though a large component of the innate immune response is common to all infections, pathogen-specific innate immune responses have been documented as well. The innate immune response is thought to be especially critical for fighting infection with Mycobacterium tuberculosis (MTB), the causative agent of tuberculosis (TB). While TB can be a deadly disease, only 5-10% of individuals infected with MTB develop active disease, and this inter-individual variation is, at least partly, heritable. Studies of inter-individual variation in the innate immune response to MTB infection may therefore shed light on the genetic basis for variation in susceptibility to TB. Yet, to date, we still do not know which properties of the innate immune response are specific to MTB infection and which represent a general response to pathogen infection. To begin addressing this gap, we infected macrophages with eight different bacterial pathogens, including different MTB strains and related mycobacteria, and studied the transcriptional response to infection. We found that although the gene expression changes were largely consistent across the bacterial infection treatments, we were able to identify a novel subset of genes whose regulation was affected specifically by infection with mycobacteria. Genetic variants that are associated with regulatory differences in these genes should be considered candidate loci for explaining inter-individual susceptibility TB. RNA-seq of monocyte-derived macrophages isolated from 6 healthy European males at 4, 18, and 48 hours post-infection with the following 8 bacteria: Mycobacterium tuberculosis (MTB) H37Rv, Mycobacterium tuberculosis GC1237, MTB GC1237, bacillus Calmette-Guérin (BCG), Mycobacterium smegmatis, Yersinia pseudotuberculosis, Salmonella typhimurium, and Staphylococcus epidermidis. table-s1.txt is a tab-delimited text file that contains the batch-corrected log2 counts per million for each of the 156 samples, as well as the Ensembl gene ID and gene name. BCG = bacillus Calmette-Guérin GC = Mycobacterium tuberculosis GC1237 Rv = Mycobacterium tuberculosis (MTB) H37Rv Rv+ = heat-inactivated MTB H37Rv Salm = Salmonella typhimurium Smeg = Mycobacterium smegmatis Staph = Staphylococcus epidermidis Yers = Yersinia pseudotuberculosis