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Chauhan V, Baptista ISC, Arsh AM, Jagadeesan R, Dash S, Ribeiro AS. Transcription Attenuation in Synthetic Promoters in Nonoverlapping Tandem Formation. Biochemistry 2024. [PMID: 38997112 DOI: 10.1021/acs.biochem.4c00012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/14/2024]
Abstract
Closely spaced promoters are ubiquitous in prokaryotic and eukaryotic genomes. How their structure and dynamics relate remains unclear, particularly for tandem formations. To study their transcriptional interference, we engineered two pairs and one trio of synthetic promoters in nonoverlapping, tandem formation, in single-copy plasmids transformed into Escherichia coli cells. From in vivo measurements, we found that these promoters in tandem formation can have attenuated transcription rates. The attenuation strength can be widely fine-tuned by the promoters' positioning, natural regulatory mechanisms, and other factors, including the antibiotic rifampicin, which is known to hamper RNAP promoter escape. From this, and supported by in silico models, we concluded that the attenuation in these constructs emerges from premature terminations generated by collisions between RNAPs elongating from upstream promoters and RNAPs occupying downstream promoters. Moreover, we found that these collisions can cause one or both RNAPs to falloff. Finally, the broad spectrum of possible, externally regulated, attenuation strengths observed in our synthetic tandem promoters suggests that they could become useful as externally controllable regulators of future synthetic circuits.
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Affiliation(s)
- Vatsala Chauhan
- Faculty of Medicine and Health Technology, Tampere University, 33520 Tampere, Finland
- Department of Cell and Molecular Biology (ICM), Uppsala University, 751 24 Uppsala, Sweden
| | - Ines S C Baptista
- Faculty of Medicine and Health Technology, Tampere University, 33520 Tampere, Finland
| | - Amir M Arsh
- Faculty of Medicine and Health Technology, Tampere University, 33520 Tampere, Finland
| | - Rahul Jagadeesan
- Faculty of Medicine and Health Technology, Tampere University, 33520 Tampere, Finland
| | - Suchintak Dash
- Faculty of Medicine and Health Technology, Tampere University, 33520 Tampere, Finland
| | - Andre S Ribeiro
- Faculty of Medicine and Health Technology, Tampere University, 33520 Tampere, Finland
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2
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Miotto P, Sorrentino R, De Giorgi S, Provvedi R, Cirillo DM, Manganelli R. Transcriptional regulation and drug resistance in Mycobacterium tuberculosis. Front Cell Infect Microbiol 2022; 12:990312. [PMID: 36118045 PMCID: PMC9480834 DOI: 10.3389/fcimb.2022.990312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2022] [Accepted: 08/11/2022] [Indexed: 11/13/2022] Open
Abstract
Bacterial drug resistance is one of the major challenges to present and future human health, as the continuous selection of multidrug resistant bacteria poses at serious risk the possibility to treat infectious diseases in the near future. One of the infection at higher risk to become incurable is tuberculosis, due to the few drugs available in the market against Mycobacterium tuberculosis. Drug resistance in this species is usually due to point mutations in the drug target or in proteins required to activate prodrugs. However, another interesting and underexplored aspect of bacterial physiology with important impact on drug susceptibility is represented by the changes in transcriptional regulation following drug exposure. The main regulators involved in this phenomenon in M. tuberculosis are the sigma factors, and regulators belonging to the WhiB, GntR, XRE, Mar and TetR families. Better understanding the impact of these regulators in survival to drug treatment might contribute to identify new drug targets and/or to design new strategies of intervention.
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Affiliation(s)
- Paolo Miotto
- Emerging Bacterial Pathogens Unit, Div. of Immunology, Transplantation and Infectious Diseases IRCCS San Raffaele Scientific Institute, Milano, Italy
| | - Rita Sorrentino
- Emerging Bacterial Pathogens Unit, Div. of Immunology, Transplantation and Infectious Diseases IRCCS San Raffaele Scientific Institute, Milano, Italy
| | - Stefano De Giorgi
- Department of Molecular Medicine, University of Padova, Padova, Italy
| | | | - Daniela Maria Cirillo
- Emerging Bacterial Pathogens Unit, Div. of Immunology, Transplantation and Infectious Diseases IRCCS San Raffaele Scientific Institute, Milano, Italy
| | - Riccardo Manganelli
- Department of Molecular Medicine, University of Padova, Padova, Italy
- *Correspondence: Riccardo Manganelli,
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Abstract
Successful treatment of tuberculosis (TB) can be hampered by Mycobacterium tuberculosis populations that are temporarily able to survive antibiotic pressure in the absence of drug resistance-conferring mutations, a phenomenon termed drug tolerance. We summarize findings on M. tuberculosis tolerance published in the past 20 years. Key M. tuberculosis responses to drug pressure are reduced growth rates, metabolic shifting, and the promotion of efflux pump activity. Metabolic shifts upon drug pressure mainly occur in M. tuberculosis's lipid metabolism and redox homeostasis, with reduced tricarboxylic acid cycle activity in favor of lipid anabolism. Increased lipid anabolism plays a role in cell wall thickening, which reduces sensitivity to most TB drugs. In addition to these general mechanisms, drug-specific mechanisms have been described. Upon isoniazid exposure, M. tuberculosis reprograms several pathways associated with mycolic acid biosynthesis. Upon rifampicin exposure, M. tuberculosis upregulates the expression of its drug target rpoB Upon bedaquiline exposure, ATP synthesis is stimulated, and the transcription factors Rv0324 and Rv0880 are activated. A better understanding of M. tuberculosis's responses to drug pressure will be important for the development of novel agents that prevent the development of drug tolerance following treatment initiation. Such agents could then contribute to novel TB treatment-shortening strategies.
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Martini MC, Zhou Y, Sun H, Shell SS. Defining the Transcriptional and Post-transcriptional Landscapes of Mycobacterium smegmatis in Aerobic Growth and Hypoxia. Front Microbiol 2019; 10:591. [PMID: 30984135 PMCID: PMC6448022 DOI: 10.3389/fmicb.2019.00591] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Accepted: 03/08/2019] [Indexed: 12/13/2022] Open
Abstract
The ability of Mycobacterium tuberculosis to infect, proliferate, and survive during long periods in the human lungs largely depends on the rigorous control of gene expression. Transcriptome-wide analyses are key to understanding gene regulation on a global scale. Here, we combine 5′-end-directed libraries with RNAseq expression libraries to gain insight into the transcriptome organization and post-transcriptional mRNA cleavage landscape in mycobacteria during log phase growth and under hypoxia, a physiologically relevant stress condition. Using the model organism Mycobacterium smegmatis, we identified 6,090 transcription start sites (TSSs) with high confidence during log phase growth, of which 67% were categorized as primary TSSs for annotated genes, and the remaining were classified as internal, antisense, or orphan, according to their genomic context. Interestingly, over 25% of the RNA transcripts lack a leader sequence, and of the coding sequences that do have leaders, 53% lack a strong consensus Shine-Dalgarno site. This indicates that like M. tuberculosis, M. smegmatis can initiate translation through multiple mechanisms. Our approach also allowed us to identify over 3,000 RNA cleavage sites, which occur at a novel sequence motif. To our knowledge, this represents the first report of a transcriptome-wide RNA cleavage site map in mycobacteria. The cleavage sites show a positional bias toward mRNA regulatory regions, highlighting the importance of post-transcriptional regulation in gene expression. We show that in low oxygen, a condition associated with the host environment during infection, mycobacteria change their transcriptomic profiles and endonucleolytic RNA cleavage is markedly reduced, suggesting a mechanistic explanation for previous reports of increased mRNA half-lives in response to stress. In addition, a number of TSSs were triggered in hypoxia, 56 of which contain the binding motif for the sigma factor SigF in their promoter regions. This suggests that SigF makes direct contributions to transcriptomic remodeling in hypoxia-challenged mycobacteria. Taken together, our data provide a foundation for further study of both transcriptional and posttranscriptional regulation in mycobacteria.
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Affiliation(s)
- M Carla Martini
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, MA, United States
| | - Ying Zhou
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, MA, United States
| | - Huaming Sun
- Program in Bioinformatics and Computational Biology, Worcester Polytechnic Institute, Worcester, MA, United States
| | - Scarlet S Shell
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, MA, United States.,Program in Bioinformatics and Computational Biology, Worcester Polytechnic Institute, Worcester, MA, United States
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5
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Song L, Jenner M, Masschelein J, Jones C, Bull MJ, Harris SR, Hartkoorn RC, Vocat A, Romero-Canelon I, Coupland P, Webster G, Dunn M, Weiser R, Paisey C, Cole ST, Parkhill J, Mahenthiralingam E, Challis GL. Discovery and Biosynthesis of Gladiolin: A Burkholderia gladioli Antibiotic with Promising Activity against Mycobacterium tuberculosis. J Am Chem Soc 2017; 139:7974-7981. [DOI: 10.1021/jacs.7b03382] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Lijiang Song
- Department
of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Matthew Jenner
- Department
of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Joleen Masschelein
- Department
of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Cerith Jones
- Organisms
and Environment Research Division, Cardiff School of Biosciences, Cardiff University, Cardiff CF10 3AT, United Kingdom
| | - Matthew J. Bull
- Organisms
and Environment Research Division, Cardiff School of Biosciences, Cardiff University, Cardiff CF10 3AT, United Kingdom
| | - Simon R. Harris
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, United Kingdom
| | - Ruben C. Hartkoorn
- Global
Health Institute, Ecole Polytechnique Fédérale de Lausanne, Station 19, 1015 Lausanne, Switzerland
| | - Anthony Vocat
- Global
Health Institute, Ecole Polytechnique Fédérale de Lausanne, Station 19, 1015 Lausanne, Switzerland
| | | | - Paul Coupland
- Organisms
and Environment Research Division, Cardiff School of Biosciences, Cardiff University, Cardiff CF10 3AT, United Kingdom
| | - Gordon Webster
- Organisms
and Environment Research Division, Cardiff School of Biosciences, Cardiff University, Cardiff CF10 3AT, United Kingdom
| | - Matthew Dunn
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, United Kingdom
| | - Rebecca Weiser
- Organisms
and Environment Research Division, Cardiff School of Biosciences, Cardiff University, Cardiff CF10 3AT, United Kingdom
| | - Christopher Paisey
- Organisms
and Environment Research Division, Cardiff School of Biosciences, Cardiff University, Cardiff CF10 3AT, United Kingdom
| | - Stewart T. Cole
- Global
Health Institute, Ecole Polytechnique Fédérale de Lausanne, Station 19, 1015 Lausanne, Switzerland
| | - Julian Parkhill
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, United Kingdom
| | - Eshwar Mahenthiralingam
- Organisms
and Environment Research Division, Cardiff School of Biosciences, Cardiff University, Cardiff CF10 3AT, United Kingdom
| | - Gregory L. Challis
- Organisms
and Environment Research Division, Cardiff School of Biosciences, Cardiff University, Cardiff CF10 3AT, United Kingdom
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Sigma Factors: Key Molecules in Mycobacterium tuberculosis Physiology and Virulence. Microbiol Spectr 2015; 2:MGM2-0007-2013. [PMID: 26082107 DOI: 10.1128/microbiolspec.mgm2-0007-2013] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Rapid adaptation to changing environments is one of the keys to the success of microorganisms. Since infection is a dynamic process, it is possible to predict that Mycobacterium tuberculosis adaptation involves continuous modulation of its global transcriptional profile in response to the changing environment found in the human body. In the last 18 years several studies have stressed the role of sigma (σ) factors in this process. These are small interchangeable subunits of the RNA polymerase holoenzyme that are required for transcriptional initiation and that determine promoter specificity. The M. tuberculosis genome encodes 13 of these proteins, one of which--the principal σ factor σA--is essential. Of the other 12 σ factors, at least 6 are required for virulence. In this article we review our current knowledge of mycobacterial σ factors, their regulons, the complex mechanisms determining their regulation, and their roles in M. tuberculosis physiology and virulence.
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Singh AK, Dutta D, Singh V, Srivastava V, Biswas RK, Singh BN. 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. Microbiologyopen 2015; 4:896-916. [PMID: 26434659 PMCID: PMC4694148 DOI: 10.1002/mbo3.288] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Revised: 08/15/2015] [Accepted: 08/18/2015] [Indexed: 12/22/2022] Open
Abstract
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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Affiliation(s)
- Anirudh K Singh
- Division of Microbiology, CSIR-Central Drug Research Institute, Lucknow, 226031, India
| | - Debashis Dutta
- Division of Microbiology, CSIR-Central Drug Research Institute, Lucknow, 226031, India
| | - Vandana Singh
- Division of Microbiology, CSIR-Central Drug Research Institute, Lucknow, 226031, India
| | - Vishal Srivastava
- Division of Microbiology, CSIR-Central Drug Research Institute, Lucknow, 226031, India
| | - Rajesh K Biswas
- Division of Microbiology, CSIR-Central Drug Research Institute, Lucknow, 226031, India
| | - Bhupendra N Singh
- Division of Microbiology, CSIR-Central Drug Research Institute, Lucknow, 226031, India
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Knapp GS, Lyubetskaya A, Peterson MW, Gomes ALC, Ma Z, Galagan JE, McDonough KA. Role of intragenic binding of cAMP responsive protein (CRP) in regulation of the succinate dehydrogenase genes Rv0249c-Rv0247c in TB complex mycobacteria. Nucleic Acids Res 2015; 43:5377-93. [PMID: 25940627 PMCID: PMC4477654 DOI: 10.1093/nar/gkv420] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2015] [Accepted: 04/19/2015] [Indexed: 11/14/2022] Open
Abstract
Bacterial pathogens adapt to changing environments within their hosts, and the signaling molecule adenosine 3', 5'-cyclic monophosphate (cAMP) facilitates this process. In this study, we characterized in vivo DNA binding and gene regulation by the cAMP-responsive protein CRP in M. bovis BCG as a model for tuberculosis (TB)-complex bacteria. Chromatin immunoprecipitation followed by deep-sequencing (ChIP-seq) showed that CRP associates with ∼900 DNA binding regions, most of which occur within genes. The most highly enriched binding region was upstream of a putative copper transporter gene (ctpB), and crp-deleted bacteria showed increased sensitivity to copper toxicity. Detailed mutational analysis of four CRP binding sites upstream of the virulence-associated Rv0249c-Rv0247c succinate dehydrogenase genes demonstrated that CRP directly regulates Rv0249c-Rv0247c expression from two promoters, one of which requires sequences intragenic to Rv0250c for maximum expression. The high percentage of intragenic CRP binding sites and our demonstration that these intragenic DNA sequences significantly contribute to biologically relevant gene expression greatly expand the genome space that must be considered for gene regulatory analyses in mycobacteria. These findings also have practical implications for an important bacterial pathogen in which identification of mutations that affect expression of drug target-related genes is widely used for rapid drug resistance screening.
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Affiliation(s)
- Gwendowlyn S Knapp
- Wadsworth Center, New York State Department of Health, 120 New Scotland Avenue, PO Box 22002, Albany, NY 12201-2002, USA
| | - Anna Lyubetskaya
- Bioinformatics Program, Boston University, Boston, MA 02215, USA
| | | | | | - Zhuo Ma
- Wadsworth Center, New York State Department of Health, 120 New Scotland Avenue, PO Box 22002, Albany, NY 12201-2002, USA
| | - James E Galagan
- Bioinformatics Program, Boston University, Boston, MA 02215, USA Department of Biomedical Engineering, Boston, MA 02215, USA Department of Microbiology, Boston University, Boston, MA 02215, USA
| | - Kathleen A McDonough
- Wadsworth Center, New York State Department of Health, 120 New Scotland Avenue, PO Box 22002, Albany, NY 12201-2002, USA Department of Biomedical Sciences, University at Albany, SUNY, Albany, NY 12201, USA
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Blasco B, Chen JM, Hartkoorn R, Sala C, Uplekar S, Rougemont J, Pojer F, Cole ST. Virulence regulator EspR of Mycobacterium tuberculosis is a nucleoid-associated protein. PLoS Pathog 2012; 8:e1002621. [PMID: 22479184 PMCID: PMC3315491 DOI: 10.1371/journal.ppat.1002621] [Citation(s) in RCA: 101] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2011] [Accepted: 02/21/2012] [Indexed: 01/18/2023] Open
Abstract
The principal virulence determinant of Mycobacterium tuberculosis (Mtb), the ESX-1 protein secretion system, is positively controlled at the transcriptional level by EspR. Depletion of EspR reportedly affects a small number of genes, both positively or negatively, including a key ESX-1 component, the espACD operon. EspR is also thought to be an ESX-1 substrate. Using EspR-specific antibodies in ChIP-Seq experiments (chromatin immunoprecipitation followed by ultra-high throughput DNA sequencing) we show that EspR binds to at least 165 loci on the Mtb genome. Included in the EspR regulon are genes encoding not only EspA, but also EspR itself, the ESX-2 and ESX-5 systems, a host of diverse cell wall functions, such as production of the complex lipid PDIM (phenolthiocerol dimycocerosate) and the PE/PPE cell-surface proteins. EspR binding sites are not restricted to promoter regions and can be clustered. This suggests that rather than functioning as a classical regulatory protein EspR acts globally as a nucleoid-associated protein capable of long-range interactions consistent with a recently established structural model. EspR expression was shown to be growth phase-dependent, peaking in the stationary phase. Overexpression in Mtb strain H37Rv revealed that EspR influences target gene expression both positively or negatively leading to growth arrest. At no stage was EspR secreted into the culture filtrate. Thus, rather than serving as a specific activator of a virulence locus, EspR is a novel nucleoid-associated protein, with both architectural and regulatory roles, that impacts cell wall functions and pathogenesis through multiple genes.
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Affiliation(s)
- Benjamin Blasco
- Global Health Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Jeffrey M. Chen
- Global Health Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Ruben Hartkoorn
- Global Health Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Claudia Sala
- Global Health Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Swapna Uplekar
- Global Health Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
- Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Jacques Rougemont
- Global Health Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
- Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Florence Pojer
- Global Health Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Stewart T. Cole
- Global Health Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
- * E-mail:
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10
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Abstract
In Mycobacterium tuberculosis the alternative sigma factor SigF controls the expression of a particular subset of genes by altering RNA polymerase specificity. Here, we utilize two genome-wide approaches to identify SigF-binding sites: chromatin immunoprecipitation (ChIP-on-chip) and microarray analysis of SigF-mediated transcripts. Since SigF is not an abundant protein in the logarithmic phase of growth, a pristinamyin IA-inducible system was used to control its expression. We identified 67 high-affinity SigF-binding sites and 16 loci where a SigF promoter directs the expression of a transcript. These loci include sigF itself, genes involved in lipid and intermediary metabolism and virulence, and at least one transcriptional regulator (Rv2884), possibly acting downstream of SigF. In addition, SigF was also found to direct the transcription of the gene for small RNA F6. Many loci were also found where SigF may be involved in antisense transcription, and in two cases (Rv1358 and Rv1870c) the SigF-dependent promoter was located within the predicted coding sequence. Quantitative PCR confirmed the microarray findings and 5'-rapid amplification of cDNA ends was used to map the SigF-specific transcriptional start points. A canonical SigF consensus promoter sequence GGTTT-N((15-17))-GGGTA was found prior to 11 genes. Together, these data help to define the SigF regulon and show that SigF not only governs expression of proteins such as the virulence factor, HbhA, but also impacts novel functions, such as noncoding RNAs and antisense transcripts.
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