Project description:Mycobacterium tuberculosis is a facultative intracellular pathogen, responsible for causing tuberculosis. The harsh environment in which M. tuberculosis survives requires this pathogen to maintain an evolutionary advantage. However, the apparent absence of horizontal gene transfer in M. tuberculosis imposes restrictions in the ways by which evolution can occur. Large scale changes in the genome can be introduced through genome reduction, recombination events and structural variation. Here, we identify a functional chimeric protein in the ppe38-71 locus, the absence of which is known to have an impact on protein secretion and virulence. To examine whether this approach was used more often by this pathogen we further develop software that detects potential gene fusion events from multigene deletions using whole-genome sequencing data. With this software we could identify a number of other putative gene-fusion events within the genomes of M. tuberculosis isolates. We were able to demonstrate the expression of one of these gene fusions at the protein level using mass spectrometry. Therefore, gene fusions may provide an additional means of evolution for M. tuberculosis in its natural environment whereby novel proteins and functions can arise.
Project description:Mycobacterium tuberculosis has the ability to persist within the host in a clinically latent stage. One important condition believed to contribute to latency is reduced access to oxygen but the response of M. tuberculosis to hypoxia is partially characterized. Virtually all dormant models against tuberculosis the vaccine tested in animals used laboratory strains H37Rv or Erdman strains. But major outbreaks of TB occur with the strains that have widely different genotypes and phenotypes compare to H37Rv. In this study, we used a commercial oligonucleotide microarray to determine the overall transcriptional response of lab strain (H37Rv) and most prevalent strains of Mycobacterium tuberculosis from South India S7 and S10 to hypoxia. Analysis of microarray results revealed that a total of 1161 genes are differentially regulated in H37Rv, among them 659 genes are upregulated and 502 genes are down regulated when > 1.5 fold change was taken as cut off. Microarray data of clinical isolates showed total of 790 genes are differentially regulated in S7 clinical isolates among which 453 are upregulated and 337 are down regulated. Interestingly numerous genes are differentially regulated in S10 clinical isolates (total of 2805 genes) and 1463 are upregulated and 1342 genes are down regulated during reduced oxygen model (Wayne’s model). Real-time quantitative RT-PCR was performed for few genes to validate the microarray results. To our knowledge, this genome-wide transcriptomics approach has produced the first insights into the response of South Indian prevalent clinical strains of M. tuberculosis when exposed to reduced oxygen stress.
Project description:Transcriptional profiling of mycobacterium tuberculosis clinical isolates in China comparing extensively drug-resistant tuberculosis with drug sensitive one.
Project description:Transcriptional profiling of M.tuberculosis to 10 mM vitamin C at 8 h. This was compared to gene expression profile of untreated M. tuberculosis culture. Organism: Mycobacterium tuberculosis H37Rv, Genotypic Technology designed Custom Mycobacterium tuberculosis H37Rv Whole Genome 8x15k GE Microarray (AMADID-020181)