1
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Sinha PR, Balasubramanian R, Hegde SR. Integrated sequence and -omic features reveal novel small proteome of Mycobacterium tuberculosis. Front Microbiol 2024; 15:1335310. [PMID: 38812687 PMCID: PMC11133741 DOI: 10.3389/fmicb.2024.1335310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Accepted: 04/15/2024] [Indexed: 05/31/2024] Open
Abstract
Bioinformatic studies on small proteins are under-represented due to difficulties in annotation posed by their small size. However, recent discoveries emphasize the functional significance of small proteins in cellular processes including cell signaling, metabolism, and adaptation to stress. In this study, we utilized a Random Forest classifier trained on sequence features, RNA-Seq, and Ribo-Seq data to uncover small proteins (smORFs) in M. tuberculosis. Independent predictions for the exponential and starvation conditions resulted in 695 potential smORFs. We examined the functional implications of these smORFs using homology searches, LC-MS/MS, and ChIP-seq data, testing their expression in diverse growth conditions, and identifying protein domains. We provide evidence that some of these smORFs could be part of operons, or exist as upstream ORFs. This expanded data resource for the proteins of M. tuberculosis would aid in fine-tuning the existing protein and gene regulatory networks, thereby improving system-wide studies. The primary goal of this study was to uncover and characterize smORFs in M. tuberculosis through bioinformatic analysis, shedding light on their functional roles and genomic organization. Further investigation of these potential smORFs would provide valuable insights into the genome organization and functional diversity of the M. tuberculosis proteome.
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Affiliation(s)
| | | | - Shubhada R. Hegde
- Institute of Bioinformatics and Applied Biotechnology (IBAB), Bengaluru, India
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2
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Ju X, Li S, Froom R, Wang L, Lilic M, Delbeau M, Campbell EA, Rock JM, Liu S. Incomplete transcripts dominate the Mycobacterium tuberculosis transcriptome. Nature 2024; 627:424-430. [PMID: 38418874 PMCID: PMC10937400 DOI: 10.1038/s41586-024-07105-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Accepted: 01/23/2024] [Indexed: 03/02/2024]
Abstract
Mycobacterium tuberculosis (Mtb) is a bacterial pathogen that causes tuberculosis (TB), an infectious disease that is responsible for major health and economic costs worldwide1. Mtb encounters diverse environments during its life cycle and responds to these changes largely by reprogramming its transcriptional output2. However, the mechanisms of Mtb transcription and how they are regulated remain poorly understood. Here we use a sequencing method that simultaneously determines both termini of individual RNA molecules in bacterial cells3 to profile the Mtb transcriptome at high resolution. Unexpectedly, we find that most Mtb transcripts are incomplete, with their 5' ends aligned at transcription start sites and 3' ends located 200-500 nucleotides downstream. We show that these short RNAs are mainly associated with paused RNA polymerases (RNAPs) rather than being products of premature termination. We further show that the high propensity of Mtb RNAP to pause early in transcription relies on the binding of the σ-factor. Finally, we show that a translating ribosome promotes transcription elongation, revealing a potential role for transcription-translation coupling in controlling Mtb gene expression. In sum, our findings depict a mycobacterial transcriptome that prominently features incomplete transcripts resulting from RNAP pausing. We propose that the pausing phase constitutes an important transcriptional checkpoint in Mtb that allows the bacterium to adapt to environmental changes and could be exploited for TB therapeutics.
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Affiliation(s)
- Xiangwu Ju
- Laboratory of Nanoscale Biophysics and Biochemistry, The Rockefeller University, New York, NY, USA
| | - Shuqi Li
- Laboratory of Host-Pathogen Biology, The Rockefeller University, New York, NY, USA
| | - Ruby Froom
- Laboratory of Host-Pathogen Biology, The Rockefeller University, New York, NY, USA
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY, USA
| | - Ling Wang
- Laboratory of Nanoscale Biophysics and Biochemistry, The Rockefeller University, New York, NY, USA
| | - Mirjana Lilic
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY, USA
| | - Madeleine Delbeau
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY, USA
| | - Elizabeth A Campbell
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY, USA
| | - Jeremy M Rock
- Laboratory of Host-Pathogen Biology, The Rockefeller University, New York, NY, USA.
| | - Shixin Liu
- Laboratory of Nanoscale Biophysics and Biochemistry, The Rockefeller University, New York, NY, USA.
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3
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Zhou Y, Sun H, Rapiejko AR, Vargas-Blanco DA, Martini MC, Chase MR, Joubran SR, Davis AB, Dainis JP, Kelly JM, Ioerger TR, Roberts LA, Fortune SM, Shell SS. Mycobacterial RNase E cleaves with a distinct sequence preference and controls the degradation rates of most Mycolicibacterium smegmatis mRNAs. J Biol Chem 2023; 299:105312. [PMID: 37802316 PMCID: PMC10641625 DOI: 10.1016/j.jbc.2023.105312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 08/29/2023] [Accepted: 09/29/2023] [Indexed: 10/08/2023] Open
Abstract
The mechanisms and regulation of RNA degradation in mycobacteria have been subject to increased interest following the identification of interplay between RNA metabolism and drug resistance. Mycobacteria encode multiple ribonucleases predicted to participate in mRNA degradation and/or processing of stable RNAs. RNase E is hypothesized to play a major role in mRNA degradation because of its essentiality in mycobacteria and its role in mRNA degradation in gram-negative bacteria. Here, we defined the impact of RNase E on mRNA degradation rates transcriptome-wide in the nonpathogenic model Mycolicibacterium smegmatis. RNase E played a rate-limiting role in degradation of the transcripts encoded by at least 89% of protein-coding genes, with leadered transcripts often being more affected by RNase E repression than leaderless transcripts. There was an apparent global slowing of transcription in response to knockdown of RNase E, suggesting that M. smegmatis regulates transcription in responses to changes in mRNA degradation. This compensation was incomplete, as the abundance of most transcripts increased upon RNase E knockdown. We assessed the sequence preferences for cleavage by RNase E transcriptome-wide in M. smegmatis and Mycobacterium tuberculosis and found a consistent bias for cleavage in C-rich regions. Purified RNase E had a clear preference for cleavage immediately upstream of cytidines, distinct from the sequence preferences of RNase E in gram-negative bacteria. We furthermore report a high-resolution map of mRNA cleavage sites in M. tuberculosis, which occur primarily within the RNase E-preferred sequence context, confirming that RNase E has a broad impact on the M. tuberculosis transcriptome.
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Affiliation(s)
- Ying Zhou
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, Massachusetts, USA
| | - Huaming Sun
- Program in Bioinformatics and Computational Biology, Worcester Polytechnic Institute, Worcester, Massachusetts, USA
| | - Abigail R Rapiejko
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, Massachusetts, USA
| | - Diego A Vargas-Blanco
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, Massachusetts, USA
| | - Maria Carla Martini
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, Massachusetts, USA
| | - Michael R Chase
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, Massachusetts, USA
| | - Samantha R Joubran
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, Massachusetts, USA
| | - Alexa B Davis
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, Massachusetts, USA
| | - Joseph P Dainis
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, Massachusetts, USA
| | - Jessica M Kelly
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, Massachusetts, USA
| | - Thomas R Ioerger
- Department of Computer Science & Engineering, Texas A&M University, College Station, Texas, USA
| | - Louis A Roberts
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, Massachusetts, USA
| | - Sarah M Fortune
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, Massachusetts, USA
| | - Scarlet S Shell
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, Massachusetts, USA.
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4
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Economou Lundeberg E, Andersson V, Wijkander M, Groenheit R, Mansjö M, Werngren J, Cortes T, Barilar I, Niemann S, Merker M, Köser CU, Davies Forsman L. In vitro activity of new combinations of β-lactam and β-lactamase inhibitors against the Mycobacterium tuberculosis complex. Microbiol Spectr 2023; 11:e0178123. [PMID: 37737628 PMCID: PMC10580993 DOI: 10.1128/spectrum.01781-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 07/24/2023] [Indexed: 09/23/2023] Open
Abstract
As meropenem-clavulanic acid is recommended for the treatment of drug-resistant tuberculosis, the repurposing of new carbapenem combinations may provide new treatment options, including oral alternatives. Therefore, we studied the in vitro activities of meropenem-vaborbactam, meropenem-clavulanic acid, and tebipenem-clavulanic acid. One hundred nine Mycobacterium tuberculosis complex (MTBC) clinical isolates were tested, of which 69 were pan-susceptible and the remaining pyrazinamide- or multidrug-resistant. Broth microdilution MICs were determined using the EUCAST reference method. Meropenem and tebipenem were tested individually and in combination with vaborbactam 8 mg/L and clavulanic-acid 2 and 4 mg/L, respectively. Whole-genome sequencing was performed to explore resistance mechanisms. Clavulanic acid lowered the modal tebipenem MIC approximately 16-fold (from 16 to 1 mg/L). The modal meropenem MIC was reduced twofold by vaborbactam compared with an approximately eightfold decrease by clavulanic acid. The only previously described high-confidence carbapenem resistance mutation, crfA T62A, was shared by a subgroup of lineage 4.3.4.1 isolates and did not correlate with elevated MICs. The presence of a β-lactamase inhibitor reduced the MTBC MICs of tebipenem and meropenem. The resulting MIC distribution was lowest for the orally available drugs tebipenem-clavulanic acid. Whether this in vitro activity translates to similar or greater clinical efficacy of tebipenem-clavulanic acid compared with the currently WHO-endorsed meropenem-clavulanic acid requires clinical studies. IMPORTANCE Repurposing of already approved antibiotics, such as β-lactams in combination with β-lactamase inhibitors, may provide new treatment alternatives for drug-resistant tuberculosis. Meropenem-clavulanic acid was more active in vitro compared to meropenem-vaborbactam. Notably, tebipenem-clavulanic acid showed even better activity, raising the potential of an all-oral treatment option. Clinical data are needed to investigate whether the better in vitro activity of tebipenem-clavulanic acid correlates with greater clinical efficacy compared with the currently WHO-endorsed meropenem-clavulanic acid.
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Affiliation(s)
| | - Viktoria Andersson
- Department of Infectious Diseases, Karolinska University Hospital, Stockholm, Sweden
| | - Maria Wijkander
- Department of Microbiology, Public Health Agency of Sweden, Stockholm, Sweden
| | - Ramona Groenheit
- Department of Microbiology, Public Health Agency of Sweden, Stockholm, Sweden
| | - Mikael Mansjö
- Department of Microbiology, Public Health Agency of Sweden, Stockholm, Sweden
| | - Jim Werngren
- Department of Microbiology, Public Health Agency of Sweden, Stockholm, Sweden
| | - Teresa Cortes
- Pathogen Gene Regulation Unit, Biomedicine Institute of Valencia (IBV), CSIC, Valencia, Spain
| | - Ivan Barilar
- Molecular and Experimental Mycobacteriology, Research Center Borstel, Borstel, Germany
- German Center for Infection Research, Partner site Hamburg-Lübeck-Borstel-Riems, Borstel, Germany
| | - Stefan Niemann
- Molecular and Experimental Mycobacteriology, Research Center Borstel, Borstel, Germany
- German Center for Infection Research, Partner site Hamburg-Lübeck-Borstel-Riems, Borstel, Germany
| | - Matthias Merker
- German Center for Infection Research, Partner site Hamburg-Lübeck-Borstel-Riems, Borstel, Germany
- Evolution of the Resistome, Research Center Borstel, Borstel, Germany
| | - Claudio U. Köser
- Department of Genetics, University of Cambridge, Cambridge, United Kingdom
| | - Lina Davies Forsman
- Department of Infectious Diseases, Karolinska University Hospital, Stockholm, Sweden
- Department of Medicine, Division of Infectious Diseases, Karolinska Institutet, Solna, Sweden
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5
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D’Halluin A, Polgar P, Kipkorir T, Patel Z, Cortes T, Arnvig KB. Premature termination of transcription is shaped by Rho and translated uORFS in Mycobacterium tuberculosis. iScience 2023; 26:106465. [PMID: 37096044 PMCID: PMC10122055 DOI: 10.1016/j.isci.2023.106465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 01/29/2023] [Accepted: 03/17/2023] [Indexed: 04/05/2023] Open
Abstract
Little is known about the decisions behind transcription elongation versus termination in the human pathogen Mycobacterium tuberculosis (M.TB). By applying Term-seq to M.TB we found that the majority of transcription termination is premature and associated with translated regions, i.e., within previously annotated or newly identified open reading frames. Computational predictions and Term-seq analysis, upon depletion of termination factor Rho, suggests that Rho-dependent transcription termination dominates all transcription termination sites (TTS), including those associated with regulatory 5' leaders. Moreover, our results suggest that tightly coupled translation, in the form of overlapping stop and start codons, may suppress Rho-dependent termination. This study provides detailed insights into novel M.TB cis-regulatory elements, where Rho-dependent, conditional termination of transcription and translational coupling together play major roles in gene expression control. Our findings contribute to a deeper understanding of the fundamental regulatory mechanisms that enable M.TB adaptation to the host environment offering novel potential points of intervention.
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Affiliation(s)
- Alexandre D’Halluin
- Structural and Molecular Biology, University College London, London WC1E 6BT, UK
| | - Peter Polgar
- Structural and Molecular Biology, University College London, London WC1E 6BT, UK
| | - Terry Kipkorir
- Structural and Molecular Biology, University College London, London WC1E 6BT, UK
| | - Zaynah Patel
- Structural and Molecular Biology, University College London, London WC1E 6BT, UK
| | - Teresa Cortes
- Instituto de Biomedicina de Valencia, CSIC, Valencia 46010, Spain
| | - Kristine B. Arnvig
- Structural and Molecular Biology, University College London, London WC1E 6BT, UK
- Corresponding author
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6
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Stiens J, Tan YY, Joyce R, Arnvig KB, Kendall SL, Nobeli I. Using a whole genome co-expression network to inform the functional characterisation of predicted genomic elements from Mycobacterium tuberculosis transcriptomic data. Mol Microbiol 2023; 119:381-400. [PMID: 36924313 DOI: 10.1111/mmi.15055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 03/08/2023] [Accepted: 03/09/2023] [Indexed: 03/18/2023]
Abstract
A whole genome co-expression network was created using Mycobacterium tuberculosis transcriptomic data from publicly available RNA-sequencing experiments covering a wide variety of experimental conditions. The network includes expressed regions with no formal annotation, including putative short RNAs and untranslated regions of expressed transcripts, along with the protein-coding genes. These unannotated expressed transcripts were among the best-connected members of the module sub-networks, making up more than half of the 'hub' elements in modules that include protein-coding genes known to be part of regulatory systems involved in stress response and host adaptation. This data set provides a valuable resource for investigating the role of non-coding RNA, and conserved hypothetical proteins, in transcriptomic remodelling. Based on their connections to genes with known functional groupings and correlations with replicated host conditions, predicted expressed transcripts can be screened as suitable candidates for further experimental validation.
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Affiliation(s)
- Jennifer Stiens
- Institute of Structural and Molecular Biology, Biological Sciences, Birkbeck, University of London, London, UK
| | - Yen Yi Tan
- Institute of Structural and Molecular Biology, Biological Sciences, Birkbeck, University of London, London, UK
| | - Rosanna Joyce
- Institute of Structural and Molecular Biology, Biological Sciences, Birkbeck, University of London, London, UK
| | - Kristine B Arnvig
- Division of Biosciences, Institute of Structural and Molecular Biology, University College London, London, UK
| | - Sharon L Kendall
- Royal Veterinary College, Centre for Emerging, Endemic and Exotic Diseases, Pathobiology and Population Sciences, Hatfield, UK
| | - Irene Nobeli
- Institute of Structural and Molecular Biology, Biological Sciences, Birkbeck, University of London, London, UK
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7
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Ju X, Li S, Froom R, Wang L, Lilic M, Campbell EA, Rock JM, Liu S. Incomplete transcripts dominate the Mycobacterium tuberculosis transcriptome. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.10.532058. [PMID: 36945399 PMCID: PMC10028986 DOI: 10.1101/2023.03.10.532058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/14/2023]
Abstract
Mycobacterium tuberculosis (Mtb) is a bacterial pathogen that causes tuberculosis, an infectious disease that inflicts major health and economic costs around the world 1 . Mtb encounters a diversity of environments during its lifecycle, and responds to these changing environments by reprogramming its transcriptional output 2 . However, the transcriptomic features of Mtb remain poorly characterized. In this work, we comprehensively profile the Mtb transcriptome using the SEnd-seq method that simultaneously captures the 5' and 3' ends of RNA 3 . Surprisingly, we find that the RNA coverage for most of the Mtb transcription units display a gradual drop-off within a 200-500 nucleotide window downstream of the transcription start site, yielding a massive number of incomplete transcripts with heterogeneous 3' ends. We further show that the accumulation of these short RNAs is mainly due to the intrinsically low processivity of the Mtb transcription machinery rather than trans-acting factors such as Rho. Finally, we demonstrate that transcription-translation coupling plays a critical role in generating full-length protein-coding transcripts in Mtb. In sum, our results depict a mycobacterial transcriptome that is dominated by incomplete RNA products, suggesting a distinctive set of transcriptional regulatory mechanisms that could be exploited for new therapeutics.
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8
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Abstract
The genus Mycobacterium contains several slow-growing human pathogens, including Mycobacterium tuberculosis, Mycobacterium leprae, and Mycobacterium avium. Mycobacterium smegmatis is a nonpathogenic and fast growing species within this genus. In 1990, a mutant of M. smegmatis, designated mc2155, that could be transformed with episomal plasmids was isolated, elevating M. smegmatis to model status as the ideal surrogate for mycobacterial research. Classical bacterial models, such as Escherichia coli, were inadequate for mycobacteria research because they have low genetic conservation, different physiology, and lack the novel envelope structure that distinguishes the Mycobacterium genus. By contrast, M. smegmatis encodes thousands of conserved mycobacterial gene orthologs and has the same cell architecture and physiology. Dissection and characterization of conserved genes, structures, and processes in genetically tractable M. smegmatis mc2155 have since provided previously unattainable insights on these same features in its slow-growing relatives. Notably, tuberculosis (TB) drugs, including the first-line drugs isoniazid and ethambutol, are active against M. smegmatis, but not against E. coli, allowing the identification of their physiological targets. Furthermore, Bedaquiline, the first new TB drug in 40 years, was discovered through an M. smegmatis screen. M. smegmatis has become a model bacterium, not only for M. tuberculosis, but for all other Mycobacterium species and related genera. With a repertoire of bioinformatic and physical resources, including the recently established Mycobacterial Systems Resource, M. smegmatis will continue to accelerate mycobacterial research and advance the field of microbiology.
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9
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Sawyer EB, Cortes T. Ribosome profiling enhances understanding of mycobacterial translation. Front Microbiol 2022; 13:976550. [PMID: 35992675 PMCID: PMC9386245 DOI: 10.3389/fmicb.2022.976550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Accepted: 07/22/2022] [Indexed: 11/21/2022] Open
Abstract
A recent addition to the -omics toolkit, ribosome profiling, enables researchers to gain insight into the process and regulation of translation by mapping fragments of mRNA protected from nuclease digestion by ribosome binding. In this review, we discuss how ribosome profiling applied to mycobacteria has led to discoveries about translational regulation. Using case studies, we show that the traditional view of “canonical” translation mechanisms needs expanding to encompass features of mycobacterial translation that are more widespread than previously recognized. We also discuss the limitations of the method and potential future developments that could yield further insight into the fundamental biology of this important human pathogen.
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Affiliation(s)
- Elizabeth B. Sawyer
- School of Life Sciences, University of Westminster, London, United Kingdom
- *Correspondence: Elizabeth B. Sawyer,
| | - Teresa Cortes
- Pathogen Gene Regulation Unit, Instituto de Biomedicina de Valencia (IBV), CSIC, Valencia, Spain
- Teresa Cortes,
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10
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Smith C, Canestrari JG, Wang AJ, Champion MM, Derbyshire KM, Gray TA, Wade JT. Pervasive translation in Mycobacterium tuberculosis. eLife 2022; 11:e73980. [PMID: 35343439 PMCID: PMC9094748 DOI: 10.7554/elife.73980] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Accepted: 03/25/2022] [Indexed: 11/13/2022] Open
Abstract
Most bacterial ORFs are identified by automated prediction algorithms. However, these algorithms often fail to identify ORFs lacking canonical features such as a length of >50 codons or the presence of an upstream Shine-Dalgarno sequence. Here, we use ribosome profiling approaches to identify actively translated ORFs in Mycobacterium tuberculosis. Most of the ORFs we identify have not been previously described, indicating that the M. tuberculosis transcriptome is pervasively translated. The newly described ORFs are predominantly short, with many encoding proteins of ≤50 amino acids. Codon usage of the newly discovered ORFs suggests that most have not been subject to purifying selection, and hence are unlikely to contribute to cell fitness. Nevertheless, we identify 90 new ORFs (median length of 52 codons) that bear the hallmarks of purifying selection. Thus, our data suggest that pervasive translation of short ORFs in Mycobacterium tuberculosis serves as a rich source for the evolution of new functional proteins.
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Affiliation(s)
- Carol Smith
- Wadsworth Center, Division of Genetics, New York State Department of HealthAlbanyUnited States
| | - Jill G Canestrari
- Wadsworth Center, Division of Genetics, New York State Department of HealthAlbanyUnited States
| | - Archer J Wang
- Wadsworth Center, Division of Genetics, New York State Department of HealthAlbanyUnited States
| | - Matthew M Champion
- Department of Chemistry and Biochemistry, University of Notre DameNotre DameUnited States
| | - Keith M Derbyshire
- Wadsworth Center, Division of Genetics, New York State Department of HealthAlbanyUnited States
- Department of Biomedical Sciences, School of Public Health, University at AlbanyNew YorkUnited States
| | - Todd A Gray
- Wadsworth Center, Division of Genetics, New York State Department of HealthAlbanyUnited States
- Department of Biomedical Sciences, School of Public Health, University at AlbanyNew YorkUnited States
| | - Joseph T Wade
- Wadsworth Center, Division of Genetics, New York State Department of HealthAlbanyUnited States
- Department of Biomedical Sciences, School of Public Health, University at AlbanyNew YorkUnited States
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11
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Stiens J, Arnvig KB, Kendall SL, Nobeli I. Challenges in defining the functional, non-coding, expressed genome of members of the Mycobacterium tuberculosis complex. Mol Microbiol 2021; 117:20-31. [PMID: 34894010 DOI: 10.1111/mmi.14862] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 12/08/2021] [Accepted: 12/09/2021] [Indexed: 12/14/2022]
Abstract
A definitive transcriptome atlas for the non-coding expressed elements of the members of the Mycobacterium tuberculosis complex (MTBC) does not exist. Incomplete lists of non-coding transcripts can be obtained for some of the reference genomes (e.g., M. tuberculosis H37Rv) but to what extent these transcripts have homologues in closely related species or even strains is not clear. This has implications for the analysis of transcriptomic data; non-coding parts of the transcriptome are often ignored in the absence of formal, reliable annotation. Here, we review the state of our knowledge of non-coding RNAs in pathogenic mycobacteria, emphasizing the disparities in the information included in commonly used databases. We then proceed to review ways of combining computational solutions for predicting the non-coding transcriptome with experiments that can help refine and confirm these predictions.
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Affiliation(s)
- Jennifer Stiens
- Institute of Structural and Molecular Biology, Biological Sciences, Birkbeck, University of London, London, UK
| | - Kristine B Arnvig
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, London, UK
| | - Sharon L Kendall
- Centre for Emerging, Endemic and Exotic Diseases, Pathobiology and Population Sciences, Royal Veterinary College, Hatfield, UK
| | - Irene Nobeli
- Institute of Structural and Molecular Biology, Biological Sciences, Birkbeck, University of London, London, UK
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12
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Grabowska AD, Andreu N, Cortes T. Translation of a Leaderless Reporter Is Robust During Exponential Growth and Well Sustained During Stress Conditions in Mycobacterium tuberculosis. Front Microbiol 2021; 12:746320. [PMID: 34603273 PMCID: PMC8485053 DOI: 10.3389/fmicb.2021.746320] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 08/26/2021] [Indexed: 11/13/2022] Open
Abstract
Mycobacterium tuberculosis expresses a large number of leaderless mRNA transcripts; these lack the 5' leader region, which usually contains the Shine-Dalgarno sequence required for translation initiation in bacteria. In M. tuberculosis, transcripts encoding proteins like toxin-antitoxin systems are predominantly leaderless and the overall ratio of leaderless to Shine-Dalgarno transcripts significantly increases during growth arrest, suggesting that leaderless translation might be important during persistence in the host. However, whether these two types of transcripts are translated with differing efficiencies during optimal growth conditions and during stress conditions that induce growth arrest, is unclear. Here, we have used the desA1 (Rv0824c) and desA2 (Rv1094) gene pair as representative for Shine-Dalgarno and leaderless transcripts in M. tuberculosis respectively; and used them to construct bioluminescent reporter strains. We detect robust leaderless translation during exponential in vitro growth, and we show that leaderless translation is more stable than Shine-Dalgarno translation during adaptation to stress conditions. These changes are independent from transcription, as transcription levels did not significantly change following quantitative real-time PCR analysis. Upon entrance into nutrient starvation and after nitric oxide exposure, leaderless translation is significantly less affected by the stress than Shine-Dalgarno translation. Similarly, during the early stages of infection of macrophages, the levels of leaderless translation are transiently more stable than those of Shine-Dalgarno translation. These results suggest that leaderless translation may offer an advantage in the physiology of M. tuberculosis. Identification of the molecular mechanisms underlying this translational regulation may provide insights into persistent infection.
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Affiliation(s)
| | | | - Teresa Cortes
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
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13
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Aseev LV, Koledinskaya LS, Bychenko OS, Boni IV. Regulation of Ribosomal Protein Synthesis in Mycobacteria: The Autogenous Control of rpsO. Int J Mol Sci 2021; 22:9679. [PMID: 34575857 PMCID: PMC8470358 DOI: 10.3390/ijms22189679] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 09/02/2021] [Accepted: 09/03/2021] [Indexed: 01/23/2023] Open
Abstract
The autogenous regulation of ribosomal protein (r-protein) synthesis plays a key role in maintaining the stoichiometry of ribosomal components in bacteria. In this work, taking the rpsO gene as a classic example, we addressed for the first time the in vivo regulation of r-protein synthesis in the mycobacteria M. smegmatis (Msm) and M. tuberculosis (Mtb). We used a strategy based on chromosomally integrated reporters under the control of the rpsO regulatory regions and the ectopic expression of Msm S15 to measure its impact on the reporter expression. Because the use of E. coli as a host appeared inefficient, a fluorescent reporter system was developed by inserting Msm or Mtb rpsO-egfp fusions into the Msm chromosome and expressing Msm S15 or E. coli S15 in trans from a novel replicative shuttle vector, pAMYC. The results of the eGFP expression measurements in Msm cells provided evidence that the rpsO gene in Msm and Mtb was feedback-regulated at the translation level. The mutagenic analysis showed that the folding of Msm rpsO 5'UTR in a pseudoknot appeared crucial for repression by both Msm S15 and E. coli S15, thus indicating a striking resemblance of the rpsO feedback control in mycobacteria and in E. coli.
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Affiliation(s)
| | | | | | - Irina V. Boni
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry RAS, 117997 Moscow, Russia; (L.V.A.); (L.S.K.); (O.S.B.)
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Kumar N, Sharma S, Kaushal PS. Protein synthesis in Mycobacterium tuberculosis as a potential target for therapeutic interventions. Mol Aspects Med 2021; 81:101002. [PMID: 34344520 DOI: 10.1016/j.mam.2021.101002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Revised: 07/11/2021] [Accepted: 07/16/2021] [Indexed: 12/18/2022]
Abstract
Mycobacterium tuberculosis (Mtb) causes one of humankind's deadliest diseases, tuberculosis. Mtb protein synthesis machinery possesses several unique species-specific features, including its ribosome that carries two mycobacterial specific ribosomal proteins, bL37 and bS22, and ribosomal RNA segments. Since the protein synthesis is a vital cellular process that occurs on the ribosome, a detailed knowledge of the structure and function of mycobacterial ribosomes is essential to understand the cell's proteome by translation regulation. Like in many bacterial species such as Bacillus subtilis and Streptomyces coelicolor, two distinct populations of ribosomes have been identified in Mtb. Under low-zinc conditions, Mtb ribosomal proteins S14, S18, L28, and L33 are replaced with their non-zinc binding paralogues. Depending upon the nature of physiological stress, species-specific modulation of translation by stress factors and toxins that interact with the ribosome have been reported. In addition, about one-fourth of messenger RNAs in mycobacteria have been reported to be leaderless, i.e., without 5' UTR regions. However, the mechanism by which they are recruited to the Mtb ribosome is not understood. In this review, we highlight the mycobacteria-specific features of the translation apparatus and propose exploiting these features to improve the efficacy and specificity of existing antibiotics used to treat tuberculosis.
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Affiliation(s)
- Niraj Kumar
- Structural Biology & Translation Regulation Laboratory, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, 121 001, India
| | - Shivani Sharma
- Structural Biology & Translation Regulation Laboratory, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, 121 001, India
| | - Prem S Kaushal
- Structural Biology & Translation Regulation Laboratory, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, 121 001, India.
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