Identification and characterization of Rv0494: a fatty acid-responsive protein of the GntR/FadR family from Mycobacterium tuberculosis

Biswas, Ratna; Dutta, Debashis; Tripathi, Ashutosh; Feng, Youjun; Banerjee, Monisha; Singh, B. N.

doi:10.1099/mic.0.066654-0

Cited by 32 publications

(26 citation statements)

References 34 publications

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“…3 ). Rv0494 is a GntR-family regulator 40 41 whose induction correlated with 10 transcriptional changes at seven genomic loci ( Fig. 3 , blue–red ring) including binding at the Rv3094c–Rv3095 locus ( Fig.…”

Section: Resultsmentioning

confidence: 99%

The DNA-binding network of Mycobacterium tuberculosi s

et al. 2015

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Mycobacterium tuberculosis (MTB) infects 30% of all humans and kills someone every 20 – 30 seconds. Here we report genome-wide binding for ~80% of all predicted MTB transcription factors (TFs), and assayed global expression following induction of each TF. The MTB DNA binding network consists of ~16,000 binding events from 154 TFs. We identify >50 TF-DNA consensus motifs and >1,150 promoter binding events directly associated with proximal gene regulation. An additional ~4,200 binding events are in promoter windows and represent strong candidates for direct transcriptional regulation under appropriate environmental conditions. However, we also identify >10,000 “dormant” DNA binding events that cannot be linked directly with proximal transcriptional control, suggesting that widespread DNA binding may be a common feature that should be considered when developing global models of coordinated gene expression.

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Section: Resultsmentioning

confidence: 99%

The DNA-binding network of Mycobacterium tuberculosi s

et al. 2015

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“…These genes also include hadB, hadC, and fbpA, along with the FAS-II gene mabA and the Ag85 gene fbpC. Few transcription regulators of MA genes have been characterized at the molecular level, namely, FasR, which activates the fas gene (15), MabR, which represses the fasII operon (fabD-acpM-kasA-kasBaccD6) and the fas gene (16), and FadR, a repressor of the fasII operon (17). As shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…A few transcription regulators that directly regulate the biosynthesis genes have been identified. FasR regulates the expression of the fas gene (15), while MabR (16) and FadR (17) regulate the expression of the fabD-accD6 cluster, the fasII operon (Fig. 1B).…”

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confidence: 99%

Evolution of Mycolic Acid Biosynthesis Genes and Their Regulation during Starvation in Mycobacterium tuberculosis

et al. 2015

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Mycobacterium tuberculosis, the etiological agent of tuberculosis, is a Gram-positive bacterium with a unique cell envelope composed of an essential outer membrane. Mycolic acids, which are very-long-chain (up to C 100 ) fatty acids, are the major components of this mycomembrane. The enzymatic pathways involved in the biosynthesis and transport of mycolates are fairly well documented and are the targets of the major antituberculous drugs. In contrast, only fragmented information is available on the expression and regulation of the biosynthesis genes. In this study, we report that the hadA, hadB, and hadC genes, which code for the mycolate biosynthesis dehydratase enzymes, are coexpressed with three genes that encode proteins of the translational apparatus. Consistent with the well-established control of the translation potential by nutrient availability, starvation leads to downregulation of the hadABC genes along with most of the genes required for the synthesis, modification, and transport of mycolates. The downregulation of a subset of the biosynthesis genes is partially dependent on Rel Mtb , the key enzyme of the stringent response. We also report the phylogenetic evolution scenario that has shaped the current genetic organization, characterized by the coregulation of the hadABC operon with genes of the translational apparatus and with genes required for the modification of the mycolates. IMPORTANCEMycobacterium tuberculosis infects one-third of the human population worldwide, and despite the available therapeutic arsenal, it continues to kill millions of people each year. There is therefore an urgent need to identify new targets and develop a better understanding of how the bacterium is adapting itself to host defenses during infection. A prerequisite of this understanding is knowledge of how this adaptive skill has been implanted by evolution. Nutrient scarcity is an environmental condition the bacterium has to cope with during infection. In many bacteria, adaptation to starvation relies partly on the stringent response. M. tuberculosis's unique outer membrane layer, the mycomembrane, is crucial for its viability and virulence. Despite its being the target of the major antituberculosis drugs, only scattered information exists on how the genes required for biosynthesis of the mycomembrane are expressed and regulated during starvation. This work has addressed this issue as a step toward the identification of new targets in the fight against M. tuberculosis. Mycobacterium tuberculosis, the etiological agent of tuberculosis, infects one-third of humans worldwide, with 9 million new cases and 1.5 million people dying each year from this disease (77). A long-standing challenge to the fight against tuberculosis is the ability of the pathogen to develop a nonreplicating, persistent, drug-tolerant form (1-3). In addition, the emergence of multidrug-resistant (MDR), extremely drug-resistant (XDR) (4, 5), and total-drug-resistant (TDR) strains (6) underscores the urgent need to identify new therapeutic targe...

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“…The clone was verified by DNA sequencing following which the ORF was relocated to the pET28a+ expression vector generating pETSigF. SigF was overexpressed as N-terminal His 6 -tagged recombinant in E. coli C41 cells, purified using Ni-NTA affinity chromatography and the purified His 6 -SigF was used to raise anti-SigF antibody in female New Zealand white rabbit, as described previously (Biswas et al 2013). Immunodetection was performed with the primary antibody (polyclonal sera at 1:2000), followed by washing and incubation with the secondary antibody (anti-rabbit IgG horseradish peroxidase conjugate at 1:40,000).…”

Section: Generation Of Anti-sigf Antibody and Immunodetection Of Sigfmentioning

confidence: 99%

Characterization of Mycobacterium smegmatis sigF mutant and its regulon: overexpression of SigF antagonist (MSMEG_1803) in M. smegmatis mimics sigF mutant phenotype, loss of pigmentation, and sensitivity to oxidative stress

et al. 2015

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In Mycobacterium smegmatis, sigF is widely expressed during different growth stages and plays role in adaptation to stationary phase and oxidative stress. Using a sigF deletion mutant of M. smegmatis mc2155, we demonstrate that SigF is not essential for growth of bacterium. Deletion of sigF results in loss of carotenoid pigmentation which rendered increased susceptibility to H2O2 induced oxidative stress in M. smegmatis. SigF modulates the cell surface architecture and lipid biosynthesis extending the repertoire of SigF function in this species. M. smegmatis SigF regulon included variety of genes expressed during exponential and stationary phases of growth and those responsible for oxidative stress, lipid biosynthesis, energy, and central intermediary metabolism. Furthermore, we report the identification of a SigF antagonist, an anti‐sigma factor (RsbW), which upon overexpression in M. smegmatis wild type strain produced a phenotype similar to M. smegmatis mc2155 ΔsigF strain. The SigF‐anti‐SigF interaction is duly validated using bacterial two‐hybrid and pull down assays. In addition, anti‐sigma factor antagonists, RsfA and RsfB were identified and their interactions with anti‐sigma factor were experimentally validated. Identification of these proteins will help decode regulatory circuit of this alternate sigma factor.

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Identification and characterization of Rv0494: a fatty acid-responsive protein of the GntR/FadR family from Mycobacterium tuberculosis

Cited by 32 publications

References 34 publications

The DNA-binding network of Mycobacterium tuberculosi s

The DNA-binding network of Mycobacterium tuberculosi s

Evolution of Mycolic Acid Biosynthesis Genes and Their Regulation during Starvation in Mycobacterium tuberculosis

Characterization of Mycobacterium smegmatis sigF mutant and its regulon: overexpression of SigF antagonist (MSMEG_1803) in M. smegmatis mimics sigF mutant phenotype, loss of pigmentation, and sensitivity to oxidative stress

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