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: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 Aerbic conditions OD600 nm of 0.4, MtbWhiB4KO vs wtMtb, biological replicates: 3 wt Mtb H37RV and 3 MtbWhiB4 KO
Project description:Mass Spectrometry based Phosphoproteomics was carried out on M. tuberculosis wild type strain H37Rv and the isogenic mutant strains MtbΔdosR, MtbΔdosS, and MtbΔdosT that were cultured in aerobic as well as hypoxic conditions. During later the oxygen was gradually deprived in cultures that were kept static.
Project description:Purpose: CsoR, a copper responsive negative regulator of Mycobacterium tuberculosis has been shown to respond to copper and bind to its own regulon in in vitro experiments. Here we examine the role of CsoR in vivo by examining the impact of deletion of csoR on the host transcriptome. Methods: csoR was knocked out of M. tuberculosis H37Rv using the specialized transduction method developed by Bardarov et al (2002), followed by removal of the hygromycin marker with plasmid pYUB870. Both wild type and confirmed csoR knockout were grown in copper free Sauton's media to late log phase before harvesting for transcriptomic studies. RNA was extracted using a modified Trizol method prior to DNAse treatment and rRNA depletion. Sequencing was done on an Illumina HiSeq 2000, filtered for quality using the FASTX-Toolkit, and mapped using Bowtie, and counts per locus generated with BedTools in the Galaxy platform. Differential expression analysis was carried out in edgeR with significantly differentially expressed genes being identified as those with ≥|2| fold differential expression between ΔcsoR and wild type strains, and an FDR < 0.05. Results: We found that 223 genes were differentially expressed between the ΔcsoR and wild type strains, 52 induced and 71 repressed. Differential expression of 10 of these genes, 6 induced and 4 repressed, was confirmed by qRT-PCR using SYBR green methodology. The only copper responsive genes identified were those within the csoR operon: csoR, Rv0968, ctpV, Rv0970, suggesting that csoR may only regulate its own operon in response to copper. Genes in the RicR regulon, another copper responsive transcriptional regulator, were not significantly differentially expressed, but some of these copper inducible genes were slightly down regulated suggesting that copper levels may be lower in the mutant strain as compared to wild type. Notably, 44 of the 48 members of the dosR regulon, responsive to hypoxic and NO stress, were induced in the mutant vs wild type suggesting that csoR is necessary for maintaining homeostasis, likely through copper regulation, within the cell. Conclusions: We have shown that CsoR is likely only directly regulating its own operon in response to copper, however it is required to maintain homeostasis, preventing a hypoxia-type stress response in the absense of copper.
Project description:We used three M. tuberculosis strains (WT H37Rv, an RV2752c deletion mutation, and the mutant complemented with an Rv2752c overexpression construct), extracted RNA from log phase cultures, and made RNAseq expression libraries as well as 5'-end-directed libraries.
Project description:HupB is a 28 kDa in Mycobacterium tuberculosis that is co-expressed with the siderophores mycobactin and carboxymycobactin upon iron limitation. High levels of all the three components are seen in low iron (LI; 0.02 µg Fe / mL) organisms, with negligible expression in high iron organisms (HI; 8 µg Fe / mL). We generated a hupB knock out mutant of M. tuberculosis (H37Rv ∆ hupB) and studied the differential expression of genes upon iron limitation in the WT H37Rv and the mutant. The RNA transcripts of the WT H37Rv, grown under high and low iron conditions of growth were isolated and subjected to microarray analysis to identify the iron-regulated genes and second, the differential expression of genes in iron-limited H37Rv ∆ hupB vs iron-limited WT H37Rv was analysed. Microarray analysis was done commercially by Genotypic Technology (Bangalore, India), an authorised service provider for Agilent Technologies. The study revealed the up-regulation of all the mbt genes of the mycobactin biosynthetic machinery in LI - H37Rv and several other reported iron-regulated genes. The salient feature of this study is the failure of LI - H37Rv ∆ hupB to show any up-regulation of the mbt genes as compared to LI - H37Rv. Among several other genes influenced by HupB, the mutant strain showed low levels of mmpL5 and mmpS5 transcripts, whose expressed products are reported to be associated with siderophore transport and biosynthesis.