1
|
Gupta S, Padmashali N, Pal D. INTERPIN: A repository for intrinsic transcription termination hairpins in bacteria. Biochimie 2023; 214:228-236. [PMID: 37499897 DOI: 10.1016/j.biochi.2023.07.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 07/19/2023] [Accepted: 07/25/2023] [Indexed: 07/29/2023]
Abstract
The large-scale detection of putative intrinsic transcription terminators is limited to only a few bacteria currently. We discovered a group of hairpins, called cluster hairpins, present within 15 nucleotides from each other. These are expected to work in tandem to cause intrinsic transcription termination (ITT), while the single hairpin can do the same alone. Therefore, exploring these ITT sites and the hairpins across bacterial genomes becomes highly desirable. INTERPIN is the largest archived collection of in silico inferred ITT hairpins in bacteria, covering 12745 bacterial genomes and encompassing ten bacterial phyla for ∼25 million hairpins. Users can obtain details on operons, individual cluster, and single ITT hairpins that were screened therein. Integrated Genome Viewer (IGV) software interactively visualizes hairpin secondary and tertiary structures in the genomic context. We also discuss statistics for the occurrence of cluster or single hairpins and other termination alternatives while showing the validation of predicted hairpins against in vivo detected hairpins. The database is freely available at http://pallab.cds.iisc.ac.in/INTERPIN/. INTERPIN (database and software) can make predictions for both AT and GC-rich genomes, which has not been achieved by any other program so far. It can also be used to improve genome annotation as well as to get predictions to improve the understanding of the ITT pathway by further analysis.
Collapse
Affiliation(s)
- Swati Gupta
- Department of Computational and Data Sciences, Indian Institute of Science, Bengaluru, 560012, Karnataka, India
| | - Namrata Padmashali
- Department of Computational and Data Sciences, Indian Institute of Science, Bengaluru, 560012, Karnataka, India
| | - Debnath Pal
- Department of Computational and Data Sciences, Indian Institute of Science, Bengaluru, 560012, Karnataka, India.
| |
Collapse
|
2
|
Ahmad E, Mitra A, Ahmed W, Mahapatra V, Hegde SR, Sala C, Cole ST, Nagaraja V. Rho-dependent transcription termination is the dominant mechanism in Mycobacterium tuberculosis. BIOCHIMICA ET BIOPHYSICA ACTA. GENE REGULATORY MECHANISMS 2023; 1866:194923. [PMID: 36822574 DOI: 10.1016/j.bbagrm.2023.194923] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 01/31/2023] [Accepted: 02/14/2023] [Indexed: 02/24/2023]
Abstract
Intrinsic and Rho-dependent transcription termination mechanisms regulate gene expression and recycle RNA polymerase in bacteria. Both the modes are well studied in Escherichia coli, and a few other organisms. The understanding of Rho function is limited in most other bacteria including mycobacteria. Here, we highlight the dominance of Rho-dependent termination in mycobacteria and validate Rho as a key regulatory factor. The lower abundance of intrinsic terminators, high cellular levels of Rho, and its genome-wide association with a majority of transcriptionally active genes indicate the pronounced role of Rho-mediated termination in Mycobacterium tuberculosis (Mtb). Rho modulates the termination of RNA synthesis for both protein-coding and stable RNA genes in Mtb. Concordantly, the depletion of Rho in mycobacteria impact its growth and enhances the transcription read-through at 3' ends of the transcription units. We demonstrate that MtbRho is catalytically active in the presence of RNA with varied secondary structures. These properties suggest an evolutionary adaptation of Rho as the efficient and preponderant mode of transcription termination in mycobacteria.
Collapse
Affiliation(s)
- Ezaz Ahmad
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru 560012, India
| | - Anirban Mitra
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru 560012, India
| | - Wareed Ahmed
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru 560012, India
| | - Varsha Mahapatra
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru 560012, India
| | - Shubhada R Hegde
- Institute of Bioinformatics and Applied Biotechnology, Bengaluru 560100, India
| | - Claudia Sala
- Monoclonal Antibody Discovery Laboratory, Fondazione Toscana Life Sciences, 53100 Siena, Italy
| | | | - Valakunja Nagaraja
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru 560012, India; Jawaharlal Nehru Centre for Advanced Scientific Research, Bengaluru 560064, India.
| |
Collapse
|
3
|
Intrinsic and Rho-dependent termination cooperate for efficient transcription termination at 3’ untranslated regions. Biochem Biophys Res Commun 2022; 628:123-132. [DOI: 10.1016/j.bbrc.2022.08.063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2022] [Revised: 08/10/2022] [Accepted: 08/22/2022] [Indexed: 11/22/2022]
|
4
|
Lammens EM, Nikel PI, Lavigne R. Exploring the synthetic biology potential of bacteriophages for engineering non-model bacteria. Nat Commun 2020; 11:5294. [PMID: 33082347 PMCID: PMC7576135 DOI: 10.1038/s41467-020-19124-x] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 09/25/2020] [Indexed: 12/26/2022] Open
Abstract
Non-model bacteria like Pseudomonas putida, Lactococcus lactis and other species have unique and versatile metabolisms, offering unique opportunities for Synthetic Biology (SynBio). However, key genome editing and recombineering tools require optimization and large-scale multiplexing to unlock the full SynBio potential of these bacteria. In addition, the limited availability of a set of characterized, species-specific biological parts hampers the construction of reliable genetic circuitry. Mining of currently available, diverse bacteriophages could complete the SynBio toolbox, as they constitute an unexplored treasure trove for fully adapted metabolic modulators and orthogonally-functioning parts, driven by the longstanding co-evolution between phage and host.
Collapse
Affiliation(s)
- Eveline-Marie Lammens
- Department of Biosystems, Laboratory of Gene Technology, KU Leuven, Kasteelpark Arenberg 21 box 2462, 3001, Leuven, BE, Belgium
| | - Pablo Ivan Nikel
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet, Building 220, 2800 Kgs, Lyngby, DK, Denmark
| | - Rob Lavigne
- Department of Biosystems, Laboratory of Gene Technology, KU Leuven, Kasteelpark Arenberg 21 box 2462, 3001, Leuven, BE, Belgium.
| |
Collapse
|
5
|
Girardin RC, McDonough KA. Small RNA Mcr11 requires the transcription factor AbmR for stable expression and regulates genes involved in the central metabolism of Mycobacterium tuberculosis. Mol Microbiol 2020; 113:504-520. [PMID: 31782837 PMCID: PMC7064933 DOI: 10.1111/mmi.14436] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 11/25/2019] [Accepted: 11/26/2019] [Indexed: 12/31/2022]
Abstract
Mycobacterium tuberculosis (Mtb), the etiologic agent of tuberculosis, must adapt to host-associated environments during infection by modulating gene expression. Small regulatory RNAs (sRNAs) are key regulators of bacterial gene expression, but their roles in Mtb are not well understood. Here, we address the expression and function of the Mtb sRNA Mcr11, which is associated with slow bacterial growth and chronic infections in mice. We found that stable expression of Mcr11 requires multiple factors specific to TB-complex bacteria, including the AbmR transcription factor. Bioinformatic analyses used to predict regulatory targets of Mcr11 identified 7-11 nucleotide regions with potential for direct base-pairing with Mcr11 immediately upstream of Rv3282, fadA3, and lipB. mcr11-dependent regulation of these genes was demonstrated using qRT-PCR and found to be responsive to the presence of fatty acids. Mutation of the putative Mcr11 base-pairing site upstream of lipB in a promoter reporter strain resulted in significant de-repression of lipB expression, similar to that observed in mcr11-deleted Mtb. These studies establish Mcr11's roles in regulating growth and central metabolism in Mtb. Our finding that multiple TB-complex-specific factors are required for production of stable Mcr11 also emphasizes the need to better understand mechanisms of sRNA expression and stability in TB.
Collapse
Affiliation(s)
- Roxie C. Girardin
- Department of Biomedical SciencesSchool of Public HealthUniversity at AlbanyAlbanyNY
| | - Kathleen A. McDonough
- Department of Biomedical SciencesSchool of Public HealthUniversity at AlbanyAlbanyNY
- Wadsworth Center, New York State Department of HealthAlbanyNY
| |
Collapse
|
6
|
Ahmad E, Hegde SR, Nagaraja V. Revisiting intrinsic transcription termination in mycobacteria: U-tract downstream of secondary structure is dispensable for termination. Biochem Biophys Res Commun 2019; 522:226-232. [PMID: 31759631 DOI: 10.1016/j.bbrc.2019.11.062] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 11/09/2019] [Indexed: 11/30/2022]
Abstract
In Escherichia coli, G/C-rich hairpin structure followed by a U-tract in the 3' region of the nascent RNA are crucial determinants for intrinsic or factor independent transcription termination. In mycobacteria, there is a scarcity of such intrinsic terminators. However, secondary structures having G/C-rich stem devoid of any U's or with suboptimal U-tracts were identified earlier as terminators and found to be functional both in vitro and in vivo. Two different observations - that a mycobacterial RNA polymerase (RNAP) does not function at intrinsic terminators devoid of U-tracts and the identification of an altogether new motif for termination in mycobacteria necessitated re-examining a number of putative terminators for their function as terminators. When these in silico identified non-canonical terminators were subjected to experimental validation, they were found to dissociate RNA from the elongating RNAP. Termination is observed when the U-tracts were reduced, or totally absent both in vitro and in vivo. Our results, thus indicate that the presence of U-tract following the G/C-rich stem in an intrinsic terminator may not be an essential determinant for transcription termination in mycobacteria.
Collapse
Affiliation(s)
- Ezaz Ahmad
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru, 560012, India
| | - Shubhada R Hegde
- Institute of Bioinformatics and Applied Biotechnology, Bengaluru, 560100, India
| | - Valakunja Nagaraja
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru, 560012, India; Jawaharlal Nehru Centre for Advanced Scientific Research, Bengaluru, 560100, India.
| |
Collapse
|
7
|
Schwenk S, Arnvig KB. Regulatory RNA in Mycobacterium tuberculosis, back to basics. Pathog Dis 2018; 76:4966984. [PMID: 29796669 PMCID: PMC7615687 DOI: 10.1093/femspd/fty035] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 04/09/2018] [Indexed: 01/17/2023] Open
Abstract
Since the turn of the millenium, RNA-based control of gene expression has added an extra dimension to the central dogma of molecular biology. Still, the roles of Mycobacterium tuberculosis regulatory RNAs and the proteins that facilitate their functions remain elusive, although there can be no doubt that RNA biology plays a central role in the baterium's adaptation to its many host environments. In this review, we have presented examples from model organisms and from M. tuberculosis to showcase the abundance and versatility of regulatory RNA, in order to emphasise the importance of these 'fine-tuners' of gene expression.
Collapse
MESH Headings
- Aconitate Hydratase/genetics
- Aconitate Hydratase/metabolism
- Bacterial Proteins/genetics
- Bacterial Proteins/metabolism
- Gene Expression Regulation, Bacterial
- Host-Pathogen Interactions
- Humans
- Mycobacterium tuberculosis/genetics
- Mycobacterium tuberculosis/metabolism
- Mycobacterium tuberculosis/pathogenicity
- Nucleic Acid Conformation
- RNA Stability
- RNA, Bacterial/genetics
- RNA, Bacterial/metabolism
- RNA, Small Cytoplasmic/genetics
- RNA, Small Cytoplasmic/metabolism
- RNA, Small Nuclear/genetics
- RNA, Small Nuclear/metabolism
- RNA, Small Untranslated/genetics
- RNA, Small Untranslated/metabolism
- Regulatory Sequences, Ribonucleic Acid
- Riboswitch
- Tuberculosis/microbiology
Collapse
Affiliation(s)
- Stefan Schwenk
- Institute for Structural and Molecular Biology, University College London, London WC1E 6BT, UK
| | - Kristine B Arnvig
- Institute for Structural and Molecular Biology, University College London, London WC1E 6BT, UK
| |
Collapse
|
8
|
Source of the Fitness Defect in Rifamycin-Resistant Mycobacterium tuberculosis RNA Polymerase and the Mechanism of Compensation by Mutations in the β' Subunit. Antimicrob Agents Chemother 2018; 62:AAC.00164-18. [PMID: 29661864 DOI: 10.1128/aac.00164-18] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Accepted: 04/09/2018] [Indexed: 11/20/2022] Open
Abstract
Mycobacterium tuberculosis is a critical threat to human health due to the increased prevalence of rifampin resistance (RMPr). Fitness defects have been observed in RMPr mutants with amino acid substitutions in the β subunit of RNA polymerase (RNAP). In clinical isolates, this fitness defect can be ameliorated by the presence of secondary mutations in the double-psi β-barrel (DPBB) domain of the β' subunit of RNAP. To identify factors contributing to the fitness defects observed in vivo, several in vitro RNA transcription assays were utilized to probe initiation, elongation, termination, and 3'-RNA hydrolysis with the wild-type and RMPrM. tuberculosis RNAPs. We found that the less prevalent RMPr mutants exhibit significantly poorer termination efficiencies relative to the wild type, an important factor for proper gene expression. We also found that several mechanistic aspects of transcription of the RMPr mutant RNAPs are impacted relative to the wild type. For the clinically most prevalent mutant, the βS450L mutant, these defects are mitigated by the presence of secondary/compensatory mutations in the DPBB domain of the β' subunit.
Collapse
|
9
|
Comprehensive Analysis and Comparison on the Codon Usage Pattern of Whole Mycobacterium tuberculosis Coding Genome from Different Area. BIOMED RESEARCH INTERNATIONAL 2018; 2018:3574976. [PMID: 29854746 PMCID: PMC5964552 DOI: 10.1155/2018/3574976] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Revised: 02/25/2018] [Accepted: 03/28/2018] [Indexed: 11/18/2022]
Abstract
Phenomenon of unequal use of synonymous codons in Mycobacterium tuberculosis is common. Codon usage bias not only plays an important regulatory role at the level of gene expression, but also helps in improving the accuracy and efficiency of translation. Meanwhile, codon usage pattern of Mycobacterium tuberculosis genome is important for interpreting evolutionary characteristics in species. In order to investigate the codon usage pattern of the Mycobacterium tuberculosis genome, 12 Mycobacterium tuberculosis genomes from different area are downloaded from the GeneBank. The correlations between G3, GC12, whole GC content, codon adaptation index, codon bias index, and so on of Mycobacterium tuberculosis genomes are calculated. The ENC-plot, relationship between A3/(A3 + T3) and G3/(G3 + C3), GC12 versus GC3 plot, and the RSCU of overall/separated genomes all show that the codon usage bias exists in all 12 Mycobacterium tuberculosis genomes. Lastly, relationship between CBI and the equalization of ENC shows a strong negative correlation between them. The relationship between protein length and GC content (GC3 and GC12) shows that more obvious differences in the GC content may be in shorter protein. These results show that codon usage bias existing in the Mycobacterium tuberculosis genomes could be used for further study on their evolutionary phenomenon.
Collapse
|
10
|
Botella L, Vaubourgeix J, Livny J, Schnappinger D. Depleting Mycobacterium tuberculosis of the transcription termination factor Rho causes pervasive transcription and rapid death. Nat Commun 2017; 8:14731. [PMID: 28348398 PMCID: PMC5379054 DOI: 10.1038/ncomms14731] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Accepted: 01/26/2017] [Indexed: 12/30/2022] Open
Abstract
Rifampicin, which inhibits bacterial RNA polymerase, provides one of the most effective treatments for tuberculosis. Inhibition of the transcription termination factor Rho is used to treat some bacterial infections, but its importance varies across bacteria. Here we show that Rho of Mycobacterium tuberculosis functions to both define the 3' ends of mRNAs and silence substantial fragments of the genome. Brief inactivation of Rho affects over 500 transcripts enriched for genes of foreign DNA elements and bacterial virulence factors. Prolonged inactivation of Rho causes extensive pervasive transcription, a genome-wide increase in antisense transcripts, and a rapid loss of viability of replicating and non-replicating M. tuberculosis in vitro and during acute and chronic infection in mice. Collectively, these data suggest that inhibition of Rho may provide an alternative strategy to treat tuberculosis with an efficacy similar to inhibition of RNA polymerase.
Collapse
Affiliation(s)
- Laure Botella
- Department of Microbiology and Immunology, Weill Cornell Medicine, 413E 69th Street, New York, New York 10021, USA
| | - Julien Vaubourgeix
- Department of Microbiology and Immunology, Weill Cornell Medicine, 413E 69th Street, New York, New York 10021, USA
| | - Jonathan Livny
- Broad Institute of MIT and Harvard, 415 Main Street, Cambridge, Massachusetts 02142, USA
| | - Dirk Schnappinger
- Department of Microbiology and Immunology, Weill Cornell Medicine, 413E 69th Street, New York, New York 10021, USA
| |
Collapse
|
11
|
Bhat AH, Pathak D, Rao A. The alr-groEL1 operon in Mycobacterium tuberculosis: an interplay of multiple regulatory elements. Sci Rep 2017; 7:43772. [PMID: 28256563 PMCID: PMC5335608 DOI: 10.1038/srep43772] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Accepted: 01/30/2017] [Indexed: 12/12/2022] Open
Abstract
Threonylcarbamoyladenosine is a universally conserved essential modification of tRNA that ensures translational fidelity in cellular milieu. TsaD, TsaB and TsaE are identified as tRNA-A37-threonylcarbamoyl (t6A)-transferase enzymes that have been reconstituted in vitro, in few bacteria recently. However, transcriptional organization and regulation of these genes are not known in any of these organisms. This study describes the intricate architecture of a complex multicistronic alr-groEL1 operon, harboring essential genes, namely tsaD, tsaB, tsaE, groES, groEL1, and alr (required for cell wall synthesis), and rimI encoding an N-α- acetyltransferase in Mycobacterium tuberculosis. Using northern blotting, RT-PCR and in vivo fluorescence assays, genes alr to groEL1 were found to constitute an ~6.3 kb heptacistronic operon with multiple internal promoters and an I-shaped intrinsic hairpin-like cis-regulatory element. A strong promoter PtsaD within the coding sequence of rimI gene is identified in M. tuberculosis, in addition. The study further proposes an amendment in the known bicistronic groESL1 operon annotation by providing evidence that groESL1 is co-transcribed as sub-operon of alr-groEL1 operon. The architecture of alr-groEL1 operon, conservation of the genetic context and a mosaic transcriptional profile displayed under various stress conditions convincingly suggest the involvement of this operon in stress adaptation in M. tuberculosis.
Collapse
Affiliation(s)
- Aadil H Bhat
- CSIR-Institute of Microbial Technology, Sector 39-A, Chandigarh-160036, India
| | - Deepika Pathak
- CSIR-Institute of Microbial Technology, Sector 39-A, Chandigarh-160036, India
| | - Alka Rao
- CSIR-Institute of Microbial Technology, Sector 39-A, Chandigarh-160036, India
| |
Collapse
|
12
|
Guerrini V, Subbian S, Santucci P, Canaan S, Gennaro ML, Pozzi G. Experimental Evolution of Mycobacterium tuberculosis in Human Macrophages Results in Low-Frequency Mutations Not Associated with Selective Advantage. PLoS One 2016; 11:e0167989. [PMID: 27959952 PMCID: PMC5154527 DOI: 10.1371/journal.pone.0167989] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Accepted: 11/23/2016] [Indexed: 11/19/2022] Open
Abstract
Isolates of the human pathogen Mycobacterium tuberculosis recovered from clinical samples exhibit genetic heterogeneity. Such variation may result from the stressful environment encountered by the pathogen inside the macrophage, which is the host cell tubercle bacilli parasitize. To study the evolution of the M. tuberculosis genome during growth inside macrophages, we developed a model of intracellular culture in which bacteria were serially passaged in macrophage-like THP-1 cells for about 80 bacterial generations. Genome sequencing of single bacterial colonies isolated before and after the infection cycles revealed that M. tuberculosis developed mutations at a rate of about 5.7 × 10−9 / bp/ generation, consistent with mutation rates calculated during in vivo infection. Analysis of mutant growth in macrophages and in mice showed that the mutations identified after the cyclic infection conferred no advantage to the mutants relative to wild-type. Furthermore, activity testing of the recombinant protein harboring one of these mutations showed that the presence of the mutation did not affect the enzymatic activity. The serial infection protocol developed in this work to study M. tuberculosis genome microevolution can be applied to exposure to stressors to determine their effect on genome remodeling during intra-macrophage growth.
Collapse
Affiliation(s)
- Valentina Guerrini
- Public Health Research Institute, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, New Jersey, United States of America
- Laboratory of Molecular Microbiology and Biotechnology, Department of Medical Biotechnologies, University of Siena, Siena, Italy
| | - Selvakumar Subbian
- Public Health Research Institute, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, New Jersey, United States of America
| | - Pierre Santucci
- Aix-Marseille Univ, Centre National de la Recherche Scientifique, Laboratoire d'Enzymologie Interfaciale et de Physiologie de la Lipolyse, Marseille, France
| | - Stéphane Canaan
- Aix-Marseille Univ, Centre National de la Recherche Scientifique, Laboratoire d'Enzymologie Interfaciale et de Physiologie de la Lipolyse, Marseille, France
| | - Maria Laura Gennaro
- Public Health Research Institute, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, New Jersey, United States of America
- * E-mail:
| | - Gianni Pozzi
- Laboratory of Molecular Microbiology and Biotechnology, Department of Medical Biotechnologies, University of Siena, Siena, Italy
| |
Collapse
|
13
|
Li R, Zhang Q, Li J, Shi H. Effects of cooperation between translating ribosome and RNA polymerase on termination efficiency of the Rho-independent terminator. Nucleic Acids Res 2015; 44:2554-63. [PMID: 26602687 PMCID: PMC4824070 DOI: 10.1093/nar/gkv1285] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Accepted: 11/05/2015] [Indexed: 01/25/2023] Open
Abstract
An experimental system was designed to measure in vivo termination efficiency (TE) of the Rho-independent terminator and position–function relations were quantified for the terminator tR2 in Escherichia coli. The terminator function was almost completely repressed when tR2 was located several base pairs downstream from the gene, and TE gradually increased to maximum values with the increasing distance between the gene and terminator. This TE–distance relation reflected a stochastic coupling of the ribosome and RNA polymerase (RNAP). Terminators located in the first 100 bp of the coding region can function efficiently. However, functional repression was observed when the terminator was located in the latter part of the coding region, and the degree of repression was determined by transcriptional and translational dynamics. These results may help to elucidate mechanisms of Rho-independent termination and reveal genomic locations of terminators and functions of the sequence that precedes terminators. These observations may have important applications in synthetic biology.
Collapse
Affiliation(s)
- Rui Li
- State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Qing Zhang
- State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Junbai Li
- Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China National Center for Nanoscience and Technology, Beijing 100190, China
| | - Hualin Shi
- State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing 100190, China
| |
Collapse
|
14
|
Mitra A, Misquitta R, Nagaraja V. Mycobacterium tuberculosis Rho is an NTPase with distinct kinetic properties and a novel RNA-binding subdomain. PLoS One 2014; 9:e107474. [PMID: 25229539 PMCID: PMC4167861 DOI: 10.1371/journal.pone.0107474] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Accepted: 08/18/2014] [Indexed: 11/29/2022] Open
Abstract
Two mechanisms--factor independent and dependent termination--ensure the completion of RNA synthesis in eubacteria. Factor-dependent mechanism relies on the Rho protein to terminate transcription by interacting with RNA polymerase. Although well studied in Escherichia coli, the properties of the Rho homologs from most bacteria are not known. The rho gene is unusually large in genus Mycobacterium and other members of actinobacteria, having ∼150 additional residues towards the amino terminal end. We describe the distinct properties of Rho from Mycobacterium tuberculosis. It is an NTPase with a preference for purine nucleoside triphosphates with kinetic properties different from E. coli homolog and an ability to use various RNA substrates. The N-terminal subdomain of MtbRho can bind to RNA by itself, and appears to contribute to the interaction of the termination factor with RNAs. Furthermore, the interaction with RNA induces changes in conformation and oligomerization of MtbRho.
Collapse
Affiliation(s)
- Anirban Mitra
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India
| | - Rachel Misquitta
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India
| | - Valakunja Nagaraja
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India
- Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, India
| |
Collapse
|
15
|
Mycobacterial RNA polymerase requires a U-tract at intrinsic terminators and is aided by NusG at suboptimal terminators. mBio 2014; 5:e00931. [PMID: 24713321 PMCID: PMC3993855 DOI: 10.1128/mbio.00931-14] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Intrinsic terminators, which encode GC-rich RNA hairpins followed immediately by a 7-to-9-nucleotide (nt) U-rich “U-tract,” play principal roles of punctuating and regulating transcription in most bacteria. However, canonical intrinsic terminators with strong U-tracts are underrepresented in some bacterial lineages, notably mycobacteria, leading to proposals that their RNA polymerases stop at noncanonical intrinsic terminators encoding various RNA structures lacking U-tracts. We generated recombinant forms of mycobacterial RNA polymerase and its major elongation factors NusA and NusG to characterize mycobacterial intrinsic termination. Using in vitro transcription assays devoid of possible mycobacterial contaminants, we established that mycobacterial RNA polymerase terminates more efficiently than Escherichia coli RNA polymerase at canonical terminators with imperfect U-tracts but does not terminate at putative terminators lacking U-tracts even in the presence of mycobacterial NusA and NusG. However, mycobacterial NusG exhibits a novel termination-stimulating activity that may allow intrinsic terminators with suboptimal U-tracts to function efficiently. Bacteria rely on transcription termination to define and regulate units of gene expression. In most bacteria, precise termination and much regulation by attenuation are accomplished by intrinsic terminators that encode GC-rich hairpins and U-tracts necessary to disrupt stable transcription elongation complexes. Thus, the apparent dearth of canonical intrinsic terminators with recognizable U-tracts in mycobacteria is of significant interest both because noncanonical intrinsic terminators could reveal novel routes to destabilize transcription complexes and because accurate understanding of termination is crucial for strategies to combat mycobacterial diseases and for computational bioinformatics generally. Our finding that mycobacterial RNA polymerase requires U-tracts for intrinsic termination, which can be aided by NusG, will guide future study of mycobacterial transcription and aid improvement of predictive algorithms to annotate bacterial genome sequences.
Collapse
|
16
|
Howard ST, Newman KL, McNulty S, Brown-Elliott BA, Vasireddy R, Bridge L, Wallace RJ. Insertion site and distribution of a genomic island conferring DNA phosphorothioation in the Mycobacterium abscessus complex. MICROBIOLOGY-SGM 2013; 159:2323-2332. [PMID: 24014661 DOI: 10.1099/mic.0.070318-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Nearly half of US clinical isolates of the emerging pathogen Mycobacterium abscessus were reported to exhibit smeared DNA during PFGE. This DNA degradation (Dnd) phenotype results from DNA phosphorothioation, a sulfur modification found in other bacteria and conferred by dnd genes located on mobile elements. Putative dnd genes are located on a 19.6 kbp genomic island (GI) in the M. abscessus type strain ATCC 19977. We confirmed that ATCC 19977(T) is Dnd-positive by PFGE and we developed a PCR assay to predict Dnd phenotype. Dnd-positive strains generated an amplicon from dndC whereas Dnd-negative strains generated a bridge amplicon that spanned the GI insertion site, indicating they lacked the entire 'Dnd-GI'. Comparative analyses of sequences from the bridge amplicon with ATCC 19977(T) revealed the Dnd-GI is flanked by 22 bp repeats in M. abscessus sensu stricto and inserted downstream of a tRNA-Ala gene and between inverted repeats. Regions flanking the Dnd-GI were highly conserved within the M. abscessus complex. Bioinformatics studies suggest the Dnd-GI inserted independently into a strain of Mycobacterium massiliense and that other species of mycobacteria also have dnd genes, supporting reports that the Dnd phenotype is common among actinomycetes. Within the M. abscessus complex, Dnd-positive clinical isolates were primarily M. abscessus sensu stricto, and tandem repeat typing indicated these isolates were highly related, confirming previous PFGE studies and revealing a widespread family of strains with significance in human disease.
Collapse
Affiliation(s)
- Susan T Howard
- Department of Microbiology, The University of Texas Health Science Center at Tyler, 11937 U.S. Highway 271, Tyler, TX, USA
| | - Kristopher L Newman
- Department of Microbiology, The University of Texas Health Science Center at Tyler, 11937 U.S. Highway 271, Tyler, TX, USA
| | - Steven McNulty
- Mycobacteria/Nocardia Laboratory, The University of Texas Health Science Center at Tyler, 11937 U.S. Highway 271, Tyler, TX, USA.,Department of Microbiology, The University of Texas Health Science Center at Tyler, 11937 U.S. Highway 271, Tyler, TX, USA
| | - Barbara A Brown-Elliott
- Mycobacteria/Nocardia Laboratory, The University of Texas Health Science Center at Tyler, 11937 U.S. Highway 271, Tyler, TX, USA.,Department of Microbiology, The University of Texas Health Science Center at Tyler, 11937 U.S. Highway 271, Tyler, TX, USA
| | - Ravikiran Vasireddy
- Mycobacteria/Nocardia Laboratory, The University of Texas Health Science Center at Tyler, 11937 U.S. Highway 271, Tyler, TX, USA.,Department of Microbiology, The University of Texas Health Science Center at Tyler, 11937 U.S. Highway 271, Tyler, TX, USA
| | - Linda Bridge
- Mycobacteria/Nocardia Laboratory, The University of Texas Health Science Center at Tyler, 11937 U.S. Highway 271, Tyler, TX, USA.,Department of Microbiology, The University of Texas Health Science Center at Tyler, 11937 U.S. Highway 271, Tyler, TX, USA
| | - Richard J Wallace
- Mycobacteria/Nocardia Laboratory, The University of Texas Health Science Center at Tyler, 11937 U.S. Highway 271, Tyler, TX, USA.,Department of Microbiology, The University of Texas Health Science Center at Tyler, 11937 U.S. Highway 271, Tyler, TX, USA
| |
Collapse
|
17
|
Gaudion A, Dawson L, Davis E, Smollett K. Characterisation of the Mycobacterium tuberculosis alternative sigma factor SigG: its operon and regulon. Tuberculosis (Edinb) 2013; 93:482-91. [PMID: 23871545 PMCID: PMC3776920 DOI: 10.1016/j.tube.2013.05.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Revised: 05/15/2013] [Accepted: 05/19/2013] [Indexed: 01/21/2023]
Abstract
A major step in the pathogenesis of Mycobacterium tuberculosis is the ability to survive inside macrophages, where it is exposed to a number of DNA damaging agents. The alternative sigma factor SigG has been shown to be upregulated by DNA damaging agents and by macrophage infection, but not to regulate genes of the DNA repair pathway. Here we show that SigG is expressed from at least two promoters, the most dominant of these being the DNA damage inducible RecA_Ndp promoter. This promoter is located within the annotated coding region of SigG and so the correct translational start site was determined experimentally and found to be 114 bp downstream of the annotated start site. Examining the gene expression profile of a SigG over-expression strain found a small number of genes to up-regulated, two of these encoded proteins containing glyoxylase-like domains.
Collapse
Affiliation(s)
- Alison Gaudion
- Division of Mycobacterial Research, MRC National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, UK
| | | | | | | |
Collapse
|
18
|
Miotto P, Forti F, Ambrosi A, Pellin D, Veiga DF, Balazsi G, Gennaro ML, Di Serio C, Ghisotti D, Cirillo DM. Genome-wide discovery of small RNAs in Mycobacterium tuberculosis. PLoS One 2012; 7:e51950. [PMID: 23284830 PMCID: PMC3526491 DOI: 10.1371/journal.pone.0051950] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Accepted: 11/06/2012] [Indexed: 01/29/2023] Open
Abstract
Only few small RNAs (sRNAs) have been characterized in Mycobacterium tuberculosis and their role in regulatory networks is still poorly understood. Here we report a genome-wide characterization of sRNAs in M. tuberculosis integrating experimental and computational analyses. Global RNA-seq analysis of exponentially growing cultures of M. tuberculosis H37Rv had previously identified 1373 sRNA species. In the present report we show that 258 (19%) of these were also identified by microarray expression. This set included 22 intergenic sRNAs, 84 sRNAs mapping within 5′/3′ UTRs, and 152 antisense sRNAs. Analysis of promoter and terminator consensus sequences identified sigma A promoter consensus sequences for 121 sRNAs (47%), terminator consensus motifs for 22 sRNAs (8.5%), and both motifs for 35 sRNAs (14%). Additionally, 20/23 candidates were visualized by Northern blot analysis and 5′ end mapping by primer extension confirmed the RNA-seq data. We also used a computational approach utilizing functional enrichment to identify the pathways targeted by sRNA regulation. We found that antisense sRNAs preferentially regulated transcription of membrane-bound proteins. Genes putatively regulated by novel cis-encoded sRNAs were enriched for two-component systems and for functional pathways involved in hydrogen transport on the membrane.
Collapse
Affiliation(s)
- Paolo Miotto
- Emerging Bacterial Pathogens Unit, S. Raffaele Scientific Institute, Milan, Italy
| | - Francesca Forti
- Dipartimento di BioScienze, University of Milan, Milan, Italy
| | - Alessandro Ambrosi
- University Statistical Center for Biomedical Sciences – Università Vita-Salute S. Raffaele, Milan, Italy
| | - Danilo Pellin
- University Statistical Center for Biomedical Sciences – Università Vita-Salute S. Raffaele, Milan, Italy
| | - Diogo F. Veiga
- Department of Systems Biology, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States of America
| | - Gabor Balazsi
- Department of Systems Biology, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States of America
| | - Maria L. Gennaro
- Public Health Research Institute, University of Medicine and Dentistry of New Jersey, Newark, New Jersey, United States of America
| | - Clelia Di Serio
- University Statistical Center for Biomedical Sciences – Università Vita-Salute S. Raffaele, Milan, Italy
| | | | - Daniela M. Cirillo
- Emerging Bacterial Pathogens Unit, S. Raffaele Scientific Institute, Milan, Italy
- * E-mail:
| |
Collapse
|
19
|
Newton-Foot M, Gey van Pittius NC. The complex architecture of mycobacterial promoters. Tuberculosis (Edinb) 2012; 93:60-74. [PMID: 23017770 DOI: 10.1016/j.tube.2012.08.003] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Revised: 07/31/2012] [Accepted: 08/06/2012] [Indexed: 01/02/2023]
Abstract
The genus Mycobacterium includes a variety of species with differing phenotypic properties, including growth rate, pathogenicity and environment- and host-specificity. Although many mycobacterial species have been extensively studied and their genomes sequenced, the reasons for phenotypic variation between closely related species remain unclear. Variation in gene expression may contribute to these characteristics and enable the bacteria to respond to changing environmental conditions. Gene expression is controlled primarily at the level of transcription, where the main element of regulation is the promoter. Transcriptional regulation and associated promoter sequences have been studied extensively in E. coli. This review describes the complex structure and characteristics of mycobacterial promoters, in comparison to the classical E. coli prokaryotic promoter structure. Some components of mycobacterial promoters are similar to those of E. coli. These include the predominant guanine residue at the transcriptional start point, conserved -10 hexamer, similar interhexameric distances, the use of ATG as a start codon, the guanine- and adenine-rich ribosome binding site and the presence of extended -10 (TGn) motifs in strong promoters. However, these components are much more variable in sequence in mycobacterial promoters and no conserved -35 hexamer sequence (clearly defined in E. coli) can be identified. This may be a result of the high G+C content of mycobacterial genomes, as well as the large number of sigma factors present in mycobacteria, which may recognise different promoter sequences. Mycobacteria possess a complex transcriptional regulatory network. Numerous regulatory motifs have been identified in mycobacterial promoters, predominantly in the interhexameric region. These are bound by specific transcriptional regulators in response to environmental changes. The combination of specific promoter sequences, transcriptional regulators and a variety of sigma factors enables rapid and specific responses to diverse conditions and different stages of infection. This review aims to provide an overview of the complex architecture of mycobacterial transcriptional regulation.
Collapse
Affiliation(s)
- Mae Newton-Foot
- DST/NRF Centre of Excellence for Biomedical Tuberculosis Research/MRC Centre for Molecular and Cellular Biology, Division of Molecular Biology and Human Genetics, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Stellenbosch University, PO Box 19063, Francie van Zijl Drive, Tygerberg 7505, South Africa.
| | | |
Collapse
|
20
|
Arnvig KB, Comas I, Thomson NR, Houghton J, Boshoff HI, Croucher NJ, Rose G, Perkins TT, Parkhill J, Dougan G, Young DB. Sequence-based analysis uncovers an abundance of non-coding RNA in the total transcriptome of Mycobacterium tuberculosis. PLoS Pathog 2011; 7:e1002342. [PMID: 22072964 PMCID: PMC3207917 DOI: 10.1371/journal.ppat.1002342] [Citation(s) in RCA: 163] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2011] [Accepted: 09/15/2011] [Indexed: 01/21/2023] Open
Abstract
RNA sequencing provides a new perspective on the genome of Mycobacterium tuberculosis by revealing an extensive presence of non-coding RNA, including long 5' and 3' untranslated regions, antisense transcripts, and intergenic small RNA (sRNA) molecules. More than a quarter of all sequence reads mapping outside of ribosomal RNA genes represent non-coding RNA, and the density of reads mapping to intergenic regions was more than two-fold higher than that mapping to annotated coding sequences. Selected sRNAs were found at increased abundance in stationary phase cultures and accumulated to remarkably high levels in the lungs of chronically infected mice, indicating a potential contribution to pathogenesis. The ability of tubercle bacilli to adapt to changing environments within the host is critical to their ability to cause disease and to persist during drug treatment; it is likely that novel post-transcriptional regulatory networks will play an important role in these adaptive responses.
Collapse
Affiliation(s)
- Kristine B Arnvig
- Division of Mycobacterial Research, MRC National Institute for Medical Research, London, United Kingdom.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
21
|
Peters JM, Vangeloff AD, Landick R. Bacterial transcription terminators: the RNA 3'-end chronicles. J Mol Biol 2011; 412:793-813. [PMID: 21439297 PMCID: PMC3622210 DOI: 10.1016/j.jmb.2011.03.036] [Citation(s) in RCA: 232] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2011] [Revised: 03/14/2011] [Accepted: 03/16/2011] [Indexed: 01/01/2023]
Abstract
The process of transcription termination is essential to proper expression of bacterial genes and, in many cases, to the regulation of bacterial gene expression. Two types of bacterial transcriptional terminators are known to control gene expression. Intrinsic terminators dissociate transcription complexes without the assistance of auxiliary factors. Rho-dependent terminators are sites of dissociation mediated by an RNA helicase called Rho. Despite decades of study, the molecular mechanisms of both intrinsic and Rho-dependent termination remain uncertain in key details. Most knowledge is based on the study of a small number of model terminators. The extent of sequence diversity among functional terminators and the extent of mechanistic variation as a function of sequence diversity are largely unknown. In this review, we consider the current state of knowledge about bacterial termination mechanisms and the relationship between terminator sequence and steps in the termination mechanism.
Collapse
Affiliation(s)
- Jason M. Peters
- Department of Biochemistry, University of Wisconsin, Madison, WI 53706, USA
- Department of Genetics, University of Wisconsin, Madison, WI 53706, USA
| | - Abbey D. Vangeloff
- Department of Biochemistry, University of Wisconsin, Madison, WI 53706, USA
| | - Robert Landick
- Department of Biochemistry, University of Wisconsin, Madison, WI 53706, USA
- Department of Bacteriology, University of Wisconsin, Madison, WI 53706, USA
| |
Collapse
|
22
|
Gardner PP, Barquist L, Bateman A, Nawrocki EP, Weinberg Z. RNIE: genome-wide prediction of bacterial intrinsic terminators. Nucleic Acids Res 2011; 39:5845-52. [PMID: 21478170 PMCID: PMC3152330 DOI: 10.1093/nar/gkr168] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Bacterial Rho-independent terminators (RITs) are important genomic landmarks involved in gene regulation and terminating gene expression. In this investigation we present RNIE, a probabilistic approach for predicting RITs. The method is based upon covariance models which have been known for many years to be the most accurate computational tools for predicting homology in structural non-coding RNAs. We show that RNIE has superior performance in model species from a spectrum of bacterial phyla. Further analysis of species where a low number of RITs were predicted revealed a highly conserved structural sequence motif enriched near the genic termini of the pathogenic Actinobacteria, Mycobacterium tuberculosis. This motif, together with classical RITs, account for up to 90% of all the significantly structured regions from the termini of M. tuberculosis genic elements. The software, predictions and alignments described below are available from http://github.com/ppgardne/RNIE.
Collapse
Affiliation(s)
- Paul P Gardner
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton CB10 1SA0, UK.
| | | | | | | | | |
Collapse
|
23
|
Mitra A, Kesarwani AK, Pal D, Nagaraja V. WebGeSTer DB--a transcription terminator database. Nucleic Acids Res 2010; 39:D129-35. [PMID: 20972211 PMCID: PMC3013805 DOI: 10.1093/nar/gkq971] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
We present WebGeSTer DB, the largest database of intrinsic transcription terminators (http://pallab.serc.iisc.ernet.in/gester). The database comprises of a million terminators identified in 1060 bacterial genome sequences and 798 plasmids. Users can obtain both graphic and tabular results on putative terminators based on default or user-defined parameters. The results are arranged in different tiers to facilitate retrieval, as per the specific requirements. An interactive map has been incorporated to visualize the distribution of terminators across the whole genome. Analysis of the results, both at the whole-genome level and with respect to terminators downstream of specific genes, offers insight into the prevalence of canonical and non-canonical terminators across different phyla. The data in the database reinforce the paradigm that intrinsic termination is a conserved and efficient regulatory mechanism in bacteria. Our database is freely accessible.
Collapse
Affiliation(s)
- Anirban Mitra
- Department of Microbiology Cell Biology, Indian Institute of Science and Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, India
| | | | | | | |
Collapse
|
24
|
Abstract
In this review, we summarize the present understanding of the Mycobacterium tuberculosis transcriptome and catalog both experimentally verified findings and computationally derived predictions. We also provide a new analysis for a range of discoveries by comparing the results of previously independent research papers. Bringing these data together and improving their accessibility should help catalyze further discoveries. This minireview also provides some general insights that may be valuable to those working to characterize the transcriptome of less-studied prokaryotes.
Collapse
|
25
|
Mitra A, Angamuthu K, Jayashree HV, Nagaraja V. Occurrence, divergence and evolution of intrinsic terminators across eubacteria. Genomics 2009; 94:110-6. [PMID: 19393739 DOI: 10.1016/j.ygeno.2009.04.004] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2009] [Revised: 04/04/2009] [Accepted: 04/16/2009] [Indexed: 10/20/2022]
Abstract
In Escherichia coli, the canonical intrinsic terminator of transcription includes a palindrome followed by a U-trail on the transcript. The apparent underrepresentation of such terminators in eubacterial genomes led us to develop a rapid and accurate algorithm, GeSTer, to predict putative intrinsic terminators. Now, we have analyzed 378 genome sequences with an improved version of GeSTer. Our results indicate that the canonical E. coli type terminators are not overwhelmingly abundant in eubacteria. The atypical structures, having stem-loop structures but lacking 'U' trail, occur downstream of genes in all the analyzed genomes but different phyla show conserved preference for different types of terminators. This propensity correlates with genomic GC content and presence of the factor, Rho. 60-70% of identified terminators in all the genomes show "optimized" stem-length and DeltaG. These results provide evidence that eubacteria extensively rely on the mechanism of intrinsic termination, with a considerable divergence in their structure, positioning and prevalence. The software and detailed results for individual genomes are freely available on request.
Collapse
Affiliation(s)
- Anirban Mitra
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India
| | | | | | | |
Collapse
|
26
|
Jaber AA, Ahmad S, Mokaddas E. Minor contribution of mutations at iniA codon 501 and embC-embA intergenic region in ethambutol-resistant clinical Mycobacterium tuberculosis isolates in Kuwait. Ann Clin Microbiol Antimicrob 2009; 8:2. [PMID: 19146672 PMCID: PMC2634755 DOI: 10.1186/1476-0711-8-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2008] [Accepted: 01/15/2009] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Ethambutol (EMB) is a first-line drug for the treatment of tuberculosis (TB). Resistance to EMB in Mycobacterium tuberculosis isolates is mediated by mutations in several genes involved in arabinan synthesis notably three emb (arabinosyl transferase) and iniA (isoniazid-inducible) genes. Most epidemiologically unrelated EMB-resistant M. tuberculosis strains contain mutations at embB codons 306, 406 and 497, embC-embA intergenic region (IGR) and iniA codon 501 (iniA501). OBJECTIVE To develop a more comprehensive molecular screen for EMB-resistance detection among epidemiologically unrelated EMB-resistant M. tuberculosis strains previously analyzed for embB codon 306, 406 and 497 mutations by including analysis of mutations at iniA501 and in embC-embA IGR. METHODS Fifty consecutive and phenotypically documented EMB-resistant and 25 pansusceptible M. tuberculosis strains isolated from 75 different TB patients over a four-year period in Kuwait were analyzed. Mutations at iniA501 were detected by PCR amplification followed by restriction fragment length polymorphism (RFLP) patterns generated with Hpy 99 I. Direct DNA sequencing was used to confirm RFLP results and for detecting mutations in embC-embA IGR. RESULTS Nearly same number of EMB-resistant M. tuberculosis strains were resistant to EMB alone and EMB together with additional resistance to rifampicin and isoniazid (9 of 50, 18% and 11 of 50, 22%, respectively). All the 25 pansusceptible strains contained wild-type sequences at iniA501 and in embC-embA IGR. The analysis of 50 EMB-resistant M. tuberculosis isolates showed that only one strain contained a mutated iniA501 while no mutation was detected in embC-embA IGR in any of the isolate. CONCLUSION Analysis of iniA501 and embC-embA IGR in epidemiologically unrelated EMB-resistant M. tuberculosis isolates in Kuwait indicate that mutations at these locations occur very infrequently and their inclusion for the development of a comprehensive molecular screen will make only minor contribution towards rapid EMB resistance detection.
Collapse
Affiliation(s)
- Al-Anoud Jaber
- Department of Microbiology, Faculty of Medicine, Kuwait University, Kuwait City, Kuwait
| | | | | |
Collapse
|