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Vázquez-Hernández M, Leedom SL, Keiler KC, Bandow JE. Physiology of trans-translation deficiency in Bacillus subtilis - a comparative proteomics study. Proteomics 2023; 23:e2200474. [PMID: 37496314 DOI: 10.1002/pmic.202200474] [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: 11/13/2022] [Revised: 06/09/2023] [Accepted: 06/12/2023] [Indexed: 07/28/2023]
Abstract
trans-Translation is the most effective ribosome rescue system known in bacteria. While it is essential in some bacteria, Bacillus subtilis possesses two additional alternative ribosome rescue mechanisms that require the proteins BrfA or RqcH. To investigate the physiology of trans-translation deficiency in the model organism B. subtilis, we compared the proteomes of B. subtilis 168 and a ΔssrA mutant in the mid-log phase using gel-free label-free quantitative proteomics. In chemically defined medium, the growth rate of the ssrA deletion mutant was 20% lower than that of B. subtilis 168. An 35 S-methionine incorporation assay demonstrated that protein synthesis rates were also lower in the ΔssrA strain. Alternative rescue factors were not detected. Among the 34 proteins overrepresented in the mutant strain were eight chemotaxis proteins. Indeed, both on LB agar and minimal medium the ΔssrA strain showed an altered motility and chemotaxis phenotype. Despite the lower growth rate, in the mutant proteome ribosomal proteins were more abundant while proteins related to amino acid biosynthesis were less abundant than in the parental strain. This overrepresentation of ribosomal proteins coupled with a lower protein synthesis rate and down-regulation of precursor supply reflects the slow ribosome recycling in the trans-translation-deficient mutant.
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Affiliation(s)
| | - Stephanie L Leedom
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania, USA
| | - Kenneth C Keiler
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania, USA
| | - Julia Elisabeth Bandow
- Applied Microbiology, Faculty of Biology and Biotechnology, Ruhr University Bochum, Bochum, Germany
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2
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Levendosky K, Janisch N, Quadri LEN. Comprehensive essentiality analysis of the Mycobacterium kansasii genome by saturation transposon mutagenesis and deep sequencing. mBio 2023; 14:e0057323. [PMID: 37350613 PMCID: PMC10470612 DOI: 10.1128/mbio.00573-23] [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: 03/07/2023] [Accepted: 05/01/2023] [Indexed: 06/24/2023] Open
Abstract
Mycobacterium kansasii (Mk) is an opportunistic pathogen that is frequently isolated from urban water systems, posing a health risk to susceptible individuals. Despite its ability to cause tuberculosis-like pulmonary disease, very few studies have probed the genetics of this opportunistic pathogen. Here, we report a comprehensive essentiality analysis of the Mk genome. Deep sequencing of a high-density library of Mk Himar1 transposon mutants revealed that 86.8% of the chromosomal thymine-adenine (TA) dinucleotide target sites were permissive to insertion, leaving 13.2% TA sites unoccupied. Our analysis identified 394 of the 5,350 annotated open reading frames (ORFs) as essential. The majority of these essential ORFs (84.8%) share essential mutual orthologs with Mycobacterium tuberculosis (Mtb). A comparative genomics analysis identified 139 Mk essential ORFs that share essential orthologs in four other species of mycobacteria. Thirteen Mk essential ORFs share orthologs in all four species that were identified as being not essential, while only two Mk essential ORFs are absent in all species compared. We used the essentiality data and a comparative genomics analysis reported here to highlight differences in essentiality between candidate Mtb drug targets and the corresponding Mk orthologs. Our findings suggest that the Mk genome encodes redundant or additional pathways that may confound validation of potential Mtb drugs and drug target candidates against the opportunistic pathogen. Additionally, we identified 57 intergenic regions containing four or more consecutive unoccupied TA sites. A disproportionally large number of these regions were located upstream of pe/ppe genes. Finally, we present an essentiality and orthology analysis of the Mk pRAW-like plasmid, pMK1248. IMPORTANCE Mk is one of the most common nontuberculous mycobacterial pathogens associated with tuberculosis-like pulmonary disease. Drug resistance emergence is a threat to the control of Mk infections, which already requires long-term, multidrug courses. A comprehensive understanding of Mk biology is critical to facilitate the development of new and more efficacious therapeutics against Mk. We combined transposon-based mutagenesis with analysis of insertion site identification data to uncover genes and other genomic regions required for Mk growth. We also compared the gene essentiality data set of Mk to those available for several other mycobacteria. This analysis highlighted key similarities and differences in the biology of Mk compared to these other species. Altogether, the genome-wide essentiality information generated and the results of the cross-species comparative genomics analysis represent valuable resources to assist the process of identifying and prioritizing potential Mk drug target candidates and to guide future studies on Mk biology.
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Affiliation(s)
- Keith Levendosky
- Department of Biology, Brooklyn College, City University of New York, Brooklyn, New York, USA
- Biology Program, Graduate Center, Biology Program, Graduate Center, City University of New York, New York, New York, USA
| | - Niklas Janisch
- Department of Biology, Brooklyn College, City University of New York, Brooklyn, New York, USA
- Biology Program, Graduate Center, Biology Program, Graduate Center, City University of New York, New York, New York, USA
| | - Luis E. N. Quadri
- Department of Biology, Brooklyn College, City University of New York, Brooklyn, New York, USA
- Biology Program, Graduate Center, Biology Program, Graduate Center, City University of New York, New York, New York, USA
- Biochemistry Program, Graduate Center, City University of New York, New York, New York, USA
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3
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Peptidyl tRNA Hydrolase Is Required for Robust Prolyl-tRNA Turnover in Mycobacterium tuberculosis. mBio 2023; 14:e0346922. [PMID: 36695586 PMCID: PMC9973355 DOI: 10.1128/mbio.03469-22] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Enzymes involved in rescuing stalled ribosomes and recycling translation machinery are ubiquitous in bacteria and required for growth. Peptidyl tRNA drop-off is a type of abortive translation that results in the release of a truncated peptide that is still bound to tRNA (peptidyl tRNA) into the cytoplasm. Peptidyl tRNA hydrolase (Pth) recycles the released tRNA by cleaving off the unfinished peptide and is essential in most bacteria. We developed a sequencing-based strategy called copper sulfate-based tRNA sequencing (Cu-tRNAseq) to study the physiological role of Pth in Mycobacterium tuberculosis (Mtb). While most peptidyl tRNA species accumulated in a strain with impaired Pth expression, peptidyl prolyl-tRNA was particularly enriched, suggesting that Pth is required for robust peptidyl prolyl-tRNA turnover. Reducing Pth levels increased Mtb's susceptibility to tRNA synthetase inhibitors that are in development to treat tuberculosis (TB) and rendered this pathogen highly susceptible to macrolides, drugs that are ordinarily ineffective against Mtb. Collectively, our findings reveal the potency of Cu-tRNAseq for profiling peptidyl tRNAs and suggest that targeting Pth would open new therapeutic approaches for TB. IMPORTANCE Peptidyl tRNA hydrolase (Pth) is an enzyme that cuts unfinished peptides off tRNA that has been prematurely released from a stalled ribosome. Pth is essential in nearly all bacteria, including the pathogen Mycobacterium tuberculosis (Mtb), but it has not been clear why. We have used genetic and novel biochemical approaches to show that when Pth levels decline in Mtb, peptidyl tRNA accumulates to such an extent that usable tRNA pools drop. Thus, Pth is needed to maintain normal tRNA levels, most strikingly for prolyl-tRNAs. Many antibiotics act on protein synthesis and could be affected by altering the availability of tRNA. This is certainly true for tRNA synthetase inhibitors, several of which are drug candidates for tuberculosis. We find that their action is potentiated by Pth depletion. Furthermore, Pth depletion results in hypersensitivity to macrolides, drugs that are not active enough under ordinary circumstances to be useful for tuberculosis.
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4
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Hegde PV, Aragaw WW, Cole MS, Jachak G, Ragunathan P, Sharma S, Harikishore A, Grüber G, Dick T, Aldrich CC. Structure activity relationship of pyrazinoic acid analogs as potential antimycobacterial agents. Bioorg Med Chem 2022; 74:117046. [PMID: 36228522 PMCID: PMC10551889 DOI: 10.1016/j.bmc.2022.117046] [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: 05/31/2022] [Revised: 09/29/2022] [Accepted: 09/30/2022] [Indexed: 11/02/2022]
Abstract
Tuberculosis (TB) remains a leading cause of infectious disease-related mortality and morbidity. Pyrazinamide (PZA) is a critical component of the first-line TB treatment regimen because of its sterilizing activity against non-replicating Mycobacterium tuberculosis (Mtb), but its mechanism of action has remained enigmatic. PZA is a prodrug converted by pyrazinamidase encoded by pncA within Mtb to the active moiety, pyrazinoic acid (POA) and PZA resistance is caused by loss-of-function mutations to pyrazinamidase. We have recently shown that POA induces targeted protein degradation of the enzyme PanD, a crucial component of the coenzyme A biosynthetic pathway essential in Mtb. Based on the newly identified mechanism of action of POA, along with the crystal structure of PanD bound to POA, we designed several POA analogs using structure for interpretation to improve potency and overcome PZA resistance. We prepared and tested ring and carboxylic acid bioisosteres as well as 3, 5, 6 substitutions on the ring to study the structure activity relationships of the POA scaffold. All the analogs were evaluated for their whole cell antimycobacterial activity, and a few representative molecules were evaluated for their binding affinity, towards PanD, through isothermal titration calorimetry. We report that analogs with ring and carboxylic acid bioisosteres did not significantly enhance the antimicrobial activity, whereas the alkylamino-group substitutions at the 3 and 5 position of POA were found to be up to 5 to 10-fold more potent than POA. Further development and mechanistic analysis of these analogs may lead to a next generation POA analog for treating TB.
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Affiliation(s)
- Pooja V Hegde
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN, USA
| | - Wassihun W Aragaw
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, NJ, USA
| | - Malcolm S Cole
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN, USA
| | - Gorakhnath Jachak
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN, USA
| | - Priya Ragunathan
- School of Biological Sciences, Nanyang Technological University, Singapore, Republic of Singapore
| | - Sachin Sharma
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN, USA
| | - Amaravadhi Harikishore
- School of Biological Sciences, Nanyang Technological University, Singapore, Republic of Singapore
| | - Gerhard Grüber
- School of Biological Sciences, Nanyang Technological University, Singapore, Republic of Singapore.
| | - Thomas Dick
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, NJ, USA; Departmentof Medical Sciences, Hackensack Meridian School of Medicine, Nutley, NJ, USA; Department of Microbiology and Immunology, Georgetown University, Washington, DC, USA.
| | - Courtney C Aldrich
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN, USA.
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Alebouyeh S, Cárdenas-Pestana JA, Vazquez L, Prados-Rosales R, Del Portillo P, Sanz J, Menéndez MC, García MJ. Iron deprivation enhances transcriptional responses to in vitro growth arrest of Mycobacterium tuberculosis. Front Microbiol 2022; 13:956602. [PMID: 36267176 PMCID: PMC9577196 DOI: 10.3389/fmicb.2022.956602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 09/07/2022] [Indexed: 11/18/2022] Open
Abstract
The establishment of Mycobacterium tuberculosis (Mtb) long-term infection in vivo depends on several factors, one of which is the availability of key nutrients such as iron (Fe). The relation between Fe deprivation inside and outside the granuloma, and the capacity of Mtb to accumulate lipids and persist in the absence of growth is not well understood. In this context, current knowledge of how Mtb modifies its lipid composition in response to growth arrest, depending on iron availability, is scarce. To shed light on these matters, in this work we compare genome-wide transcriptomic and lipidomic profiles of Mtb at exponential and stationary growth phases using cultures with glycerol as a carbon source, in the presence or absence of iron. As a result, we found that transcriptomic responses to growth arrest, considered as the transition from exponential to stationary phase, are iron dependent for as many as 714 genes (iron-growth interaction contrast, FDR <0.05), and that, in a majority of these genes, iron deprivation enhances the magnitude of the transcriptional responses to growth arrest in either direction. On the one hand, genes whose upregulation upon growth arrest is enhanced by iron deprivation were enriched in functional terms related to homeostasis of ion metals, and responses to several stressful cues considered cardinal features of the intracellular environment. On the other hand, genes showing negative responses to growth arrest that are stronger in iron-poor medium were enriched in energy production processes (TCA cycle, NADH dehydrogenation and cellular respiration), and key controllers of ribosomal activity shut-down, such as the T/A system mazE6/F6. Despite of these findings, a main component of the cell envelope, lipid phthiocerol dimycocerosate (PDIM), was not detected in the stationary phase regardless of iron availability, suggesting that lipid changes during Mtb adaptation to non-dividing phenotypes appear to be iron-independent. Taken together, our results indicate that environmental iron levels act as a key modulator of the intensity of the transcriptional adaptations that take place in the bacterium upon its transition between dividing and dormant-like phenotypes in vitro.
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Affiliation(s)
- Sogol Alebouyeh
- Department of Preventive Medicine and Public Health and Microbiology, School of Medicine, Autonomous University of Madrid, Madrid, Spain
| | - Jorge A. Cárdenas-Pestana
- Department of Theoretical Physics, University of Zaragoza, Zaragoza, Spain
- Institute for Biocomputation and Physics of Complex Systems (BIFI), University of Zaragoza, Zaragoza, Spain
| | - Lucia Vazquez
- Department of Preventive Medicine and Public Health and Microbiology, School of Medicine, Autonomous University of Madrid, Madrid, Spain
| | - Rafael Prados-Rosales
- Department of Preventive Medicine and Public Health and Microbiology, School of Medicine, Autonomous University of Madrid, Madrid, Spain
| | | | - Joaquín Sanz
- Department of Theoretical Physics, University of Zaragoza, Zaragoza, Spain
- Institute for Biocomputation and Physics of Complex Systems (BIFI), University of Zaragoza, Zaragoza, Spain
- *Correspondence: Maria J. García,
| | - Maria Carmen Menéndez
- Department of Preventive Medicine and Public Health and Microbiology, School of Medicine, Autonomous University of Madrid, Madrid, Spain
- Maria Carmen Menéndez,
| | - Maria J. García
- Department of Preventive Medicine and Public Health and Microbiology, School of Medicine, Autonomous University of Madrid, Madrid, Spain
- Joaquín Sanz,
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6
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Jadhav P, Chen Y, Butzin N, Buceta J, Urchueguía A. Bacterial degrons in synthetic circuits. Open Biol 2022; 12:220180. [PMID: 35975648 PMCID: PMC9382460 DOI: 10.1098/rsob.220180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Bacterial proteases are a promising post-translational regulation strategy in synthetic circuits because they recognize specific amino acid degradation tags (degrons) that can be fine-tuned to modulate the degradation levels of tagged proteins. For this reason, recent efforts have been made in the search for new degrons. Here we review the up-to-date applications of degradation tags for circuit engineering in bacteria. In particular, we pay special attention to the effects of degradation bottlenecks in synthetic oscillators and introduce mathematical approaches to study queueing that enable the quantitative modelling of proteolytic queues.
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Affiliation(s)
- Prajakta Jadhav
- Department of Biology and Microbiology, South Dakota State University, Brookings, SD, USA
| | - Yanyan Chen
- Program for Computational and Systems Biology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Nicholas Butzin
- Department of Biology and Microbiology, South Dakota State University, Brookings, SD, USA
| | - Javier Buceta
- Institute for Integrative Systems Biology (I2SysBio, CSIC-UV), Paterna, Valencia 46980, Spain
| | - Arantxa Urchueguía
- Department of Biology and Microbiology, South Dakota State University, Brookings, SD, USA.,Institute for Integrative Systems Biology (I2SysBio, CSIC-UV), Paterna, Valencia 46980, Spain
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7
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Li S, Poulton NC, Chang JS, Azadian ZA, DeJesus MA, Ruecker N, Zimmerman MD, Eckartt KA, Bosch B, Engelhart CA, Sullivan DF, Gengenbacher M, Dartois VA, Schnappinger D, Rock JM. CRISPRi chemical genetics and comparative genomics identify genes mediating drug potency in Mycobacterium tuberculosis. Nat Microbiol 2022; 7:766-779. [PMID: 35637331 PMCID: PMC9159947 DOI: 10.1038/s41564-022-01130-y] [Citation(s) in RCA: 70] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Accepted: 04/21/2022] [Indexed: 12/14/2022]
Abstract
Mycobacterium tuberculosis (Mtb) infection is notoriously difficult to treat. Treatment efficacy is limited by Mtb's intrinsic drug resistance, as well as its ability to evolve acquired resistance to all antituberculars in clinical use. A deeper understanding of the bacterial pathways that influence drug efficacy could facilitate the development of more effective therapies, identify new mechanisms of acquired resistance, and reveal overlooked therapeutic opportunities. Here we developed a CRISPR interference chemical-genetics platform to titrate the expression of Mtb genes and quantify bacterial fitness in the presence of different drugs. We discovered diverse mechanisms of intrinsic drug resistance, unveiling hundreds of potential targets for synergistic drug combinations. Combining chemical genetics with comparative genomics of Mtb clinical isolates, we further identified several previously unknown mechanisms of acquired drug resistance, one of which is associated with a multidrug-resistant tuberculosis outbreak in South America. Lastly, we found that the intrinsic resistance factor whiB7 was inactivated in an entire Mtb sublineage endemic to Southeast Asia, presenting an opportunity to potentially repurpose the macrolide antibiotic clarithromycin to treat tuberculosis. This chemical-genetic map provides a rich resource to understand drug efficacy in Mtb and guide future tuberculosis drug development and treatment.
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Affiliation(s)
- Shuqi Li
- Laboratory of Host-Pathogen Biology, The Rockefeller University, New York, NY, USA
| | - Nicholas C Poulton
- Laboratory of Host-Pathogen Biology, The Rockefeller University, New York, NY, USA
| | - Jesseon S Chang
- Laboratory of Host-Pathogen Biology, The Rockefeller University, New York, NY, USA
| | - Zachary A Azadian
- Laboratory of Host-Pathogen Biology, The Rockefeller University, New York, NY, USA
| | - Michael A DeJesus
- Laboratory of Host-Pathogen Biology, The Rockefeller University, New York, NY, USA
| | - Nadine Ruecker
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA
| | - Matthew D Zimmerman
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, NJ, USA
| | - Kathryn A Eckartt
- Laboratory of Host-Pathogen Biology, The Rockefeller University, New York, NY, USA
| | - Barbara Bosch
- Laboratory of Host-Pathogen Biology, The Rockefeller University, New York, NY, USA
| | - Curtis A Engelhart
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA
| | - Daniel F Sullivan
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA
| | - Martin Gengenbacher
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, NJ, USA
- Hackensack Meridian School of Medicine, Hackensack Meridian Health, Nutley, NJ, USA
| | - Véronique A Dartois
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, NJ, USA
- Hackensack Meridian School of Medicine, Hackensack Meridian Health, Nutley, NJ, USA
| | - Dirk Schnappinger
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA
| | - Jeremy M Rock
- Laboratory of Host-Pathogen Biology, The Rockefeller University, New York, NY, USA.
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8
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Dawson CC, Cummings JE, Starkey JM, Slayden RA. Discovery of a novel type IIb RelBE toxin-antitoxin system in Mycobacterium tuberculosis defined by co-regulation with an antisense RNA. Mol Microbiol 2022; 117:1419-1433. [PMID: 35526138 PMCID: PMC9325379 DOI: 10.1111/mmi.14917] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 04/30/2022] [Accepted: 05/05/2022] [Indexed: 11/29/2022]
Abstract
Toxin‐antitoxin loci regulate adaptive responses to stresses associated with the host environment and drug exposure. Phylogenomic studies have shown that Mycobacterium tuberculosis encodes a naturally expanded type II toxin‐antitoxin system, including ParDE/RelBE superfamily members. Type II toxins are presumably regulated exclusively through protein–protein interactions with type II antitoxins. However, experimental observations in M. tuberculosis indicated that additional control mechanisms regulate RelBE2 type II loci under host‐associated stress conditions. Herein, we describe for the first time a novel antisense RNA, termed asRelE2, that co‐regulates RelE2 production via targeted processing by the Mtb RNase III, Rnc. We find that convergent expression of this coding‐antisense hybrid TA locus, relBE2‐asrelE2, is controlled in a cAMP‐dependent manner by the essential cAMP receptor protein transcription factor, Crp, in response to the host‐associated stresses of low pH and nutrient limitation. Ex vivo survival studies with relE2 and asrelE2 knockout strains showed that RelE2 contributes to Mtb survival in activated macrophages and low pH to nutrient limitation. To our knowledge, this is the first report of a novel tripartite type IIb TA loci and antisense post‐transcriptional regulation of a type II TA loci.
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Affiliation(s)
- Clinton C Dawson
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins.,Endolytix Technology, Inc. Beverly, 01915
| | - Jason E Cummings
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins
| | - Julie M Starkey
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins
| | - Richard A Slayden
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins
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9
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Burgos R, Weber M, Gallo C, Lluch-Senar M, Serrano L. Widespread ribosome stalling in a genome-reduced bacterium and the need for translational quality control. iScience 2021; 24:102985. [PMID: 34485867 PMCID: PMC8403727 DOI: 10.1016/j.isci.2021.102985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 07/22/2021] [Accepted: 08/11/2021] [Indexed: 11/21/2022] Open
Abstract
Trans-translation is a ubiquitous bacterial mechanism of ribosome rescue mediated by a transfer-messenger RNA (tmRNA) that adds a degradation tag to the truncated nascent polypeptide. Here, we characterize this quality control system in a genome-reduced bacterium, Mycoplasma pneumoniae (MPN), and perform a comparative analysis of protein quality control components in slow and fast-growing prokaryotes. We show in vivo that in MPN the sole quality control cytoplasmic protease (Lon) degrades efficiently tmRNA-tagged proteins. Analysis of tmRNA-mutants encoding a tag resistant to proteolysis reveals extensive tagging activity under normal growth. Unlike knockout strains, these mutants are viable demonstrating the requirement of tmRNA-mediated ribosome recycling. Chaperone and Lon steady-state levels maintain proteostasis in these mutants suggesting a model in which co-evolution of Lon and their substrates offer simple mechanisms of regulation without specialized degradation machineries. Finally, comparative analysis shows relative increase in Lon/Chaperone levels in slow-growing bacteria suggesting physiological adaptation to growth demand. Lon degrades efficiently tmRNA-tagged proteins in a genome-reduced bacterium tmRNA-tag mutants are viable and reveal extensive tagging activity in M. pneumoniae Co-evolution of Lon and their substrates offer simple mechanisms of regulation Chaperone and Lon relative levels correlate with bacterial growth rates
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Affiliation(s)
- Raul Burgos
- Centre for Genomic Regulation (CRG), the Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona 08003, Spain
- Corresponding author
| | - Marc Weber
- Centre for Genomic Regulation (CRG), the Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona 08003, Spain
| | - Carolina Gallo
- Centre for Genomic Regulation (CRG), the Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona 08003, Spain
| | - Maria Lluch-Senar
- Centre for Genomic Regulation (CRG), the Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona 08003, Spain
| | - Luis Serrano
- Centre for Genomic Regulation (CRG), the Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona 08003, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
- ICREA, Pg. Lluis Companys 23, Barcelona 08010, Spain
- Corresponding author
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10
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Genome-Wide Essentiality Analysis of Mycobacterium abscessus by Saturated Transposon Mutagenesis and Deep Sequencing. mBio 2021; 12:e0104921. [PMID: 34126767 PMCID: PMC8262987 DOI: 10.1128/mbio.01049-21] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Mycobacterium abscessus is an emerging opportunistic human pathogen that naturally resists most major classes of antibiotics, making infections difficult to treat. Thus far, little is known about M. abscessus physiology, pathogenesis, and drug resistance. Genome-wide analyses have comprehensively catalogued genes with essential functions in Mycobacterium tuberculosis and Mycobacterium avium subsp. hominissuis (here, M. avium) but not in M. abscessus. By optimizing transduction conditions, we achieved full saturation of TA insertion sites with Himar1 transposon mutagenesis in the M. abscessus ATCC 19977T genome, as confirmed by deep sequencing prior to essentiality analyses of annotated genes and other genomic features. The overall densities of inserted TA sites (85.7%), unoccupied TA sites (14.3%), and nonpermissive TA sites (8.1%) were similar to results in M. tuberculosis and M. avium. Of the 4,920 annotated genes, 326 were identified as essential, 269 (83%) of which have mutual homology with essential M. tuberculosis genes, while 39 (12%) are homologous to genes that are not essential in M. tuberculosis and M. avium, and 11 (3.4%) only have homologs in M. avium. Interestingly, 7 (2.1%) essential M. abscessus genes have no homologs in either M. tuberculosis or M. avium, two of which were found in phage-like elements. Most essential genes are involved in DNA replication, RNA transcription and translation, and posttranslational events to synthesize important macromolecules. Some essential genes may be involved in M. abscessus pathogenesis and antibiotics response, including certain essential tRNAs and new short open reading frames. Our findings will help to pave the way for better understanding of M. abscessus and benefit development of novel bactericidal drugs against M. abscessus. IMPORTANCE Limited knowledge regarding Mycobacterium abscessus pathogenesis and intrinsic resistance to most classes of antibiotics is a major obstacle to developing more effective strategies to prevent and mitigate disease. Using optimized procedures for Himar1 transposon mutagenesis and deep sequencing, we performed a comprehensive analysis to identify M. abscessus genetic elements essential for in vitro growth and compare them to similar data sets for M. tuberculosis and M. avium subsp. hominissuis. Most essential M. abscessus genes have mutual homology with essential M. tuberculosis genes, providing a foundation for leveraging available knowledge from M. tuberculosis to develop more effective drugs and other interventions against M. abscessus. A small number of essential genes unique to M. abscessus deserve further attention to gain insights into what makes M. abscessus different from other mycobacteria. The essential genes and other genomic features such as short open reading frames and noncoding RNA identified here will provide useful information for future study of M. abscessus pathogenicity and new drug development.
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11
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Müller C, Crowe-McAuliffe C, Wilson DN. Ribosome Rescue Pathways in Bacteria. Front Microbiol 2021; 12:652980. [PMID: 33815344 PMCID: PMC8012679 DOI: 10.3389/fmicb.2021.652980] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 02/23/2021] [Indexed: 12/18/2022] Open
Abstract
Ribosomes that become stalled on truncated or damaged mRNAs during protein synthesis must be rescued for the cell to survive. Bacteria have evolved a diverse array of rescue pathways to remove the stalled ribosomes from the aberrant mRNA and return them to the free pool of actively translating ribosomes. In addition, some of these pathways target the damaged mRNA and the incomplete nascent polypeptide chain for degradation. This review highlights the recent developments in our mechanistic understanding of bacterial ribosomal rescue systems, including drop-off, trans-translation mediated by transfer-messenger RNA and small protein B, ribosome rescue by the alternative rescue factors ArfA and ArfB, as well as Bacillus ribosome rescue factor A, an additional rescue system found in some Gram-positive bacteria, such as Bacillus subtilis. Finally, we discuss the recent findings of ribosome-associated quality control in particular bacterial lineages mediated by RqcH and RqcP. The importance of rescue pathways for bacterial survival suggests they may represent novel targets for the development of new antimicrobial agents against multi-drug resistant pathogenic bacteria.
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Affiliation(s)
| | | | - Daniel N. Wilson
- Institute for Biochemistry and Molecular Biology, University of Hamburg, Hamburg, Germany
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12
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Li K, Yang Z, Gu J, Luo M, Deng J, Chen Y. Characterization of pncA Mutations and Prediction of PZA Resistance in Mycobacterium tuberculosis Clinical Isolates From Chongqing, China. Front Microbiol 2021; 11:594171. [PMID: 33505367 PMCID: PMC7832174 DOI: 10.3389/fmicb.2020.594171] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 11/26/2020] [Indexed: 01/17/2023] Open
Abstract
Pyrazinamide (PZA) is widely used to treat drug-sensitive or multidrug resistance tuberculosis. However, conventional PZA susceptibility tests of clinical isolates are rather difficult because of the requirement of acid pH. Since resistance to pyrazinamide is primary mediated by mutation of pncA, an alternative way of PZA susceptibility test is to analyze the pyrazinamidase activities of Mycobacterium tuberculosis clinical isolates. Therefore, a database containing the full spectrum of pncA mutations along with pyrazinamidase activities will be beneficial. To characterize mutations of pncA in M. tuberculosis from Chongqing, China, the pncA gene was sequenced and analyzed in 465 clinical isolates. A total of 124 types of mutations were identified in 424 drug-resistant isolates, while no mutation was identified in the 31 pan-susceptible isolates. Ninety-four of the 124 mutations had previously been reported, and 30 new mutations were identified. Based on reported literatures, 294 isolates could be predicted resistant to pyrazinamide. Furthermore, pyrazinamidase activities of the 30 new mutations were tested using the Escherichia coli pncA gene knockout strain. The results showed that 24 of these new mutations (28 isolates) led to loss of pyrazinamidase activity and six (8 isolates) of them did not. Taken together, 322 isolates with pncA mutations could be predicted to be PZA resistant among the 424 drug-resistant isolates tested. Analysis of pncA mutations and their effects on pyrazinamidase activity will not only enrich our knowledge of comprehensive pncA mutations related with PZA resistance but also facilitate rapid molecular diagnosis of pyrazinamide resistance in M. tuberculosis.
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Affiliation(s)
- Kun Li
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China.,Central Laboratory, Chongqing Public Health Medical Center, Chongqing, China
| | - Zhongping Yang
- Central Laboratory, Chongqing Public Health Medical Center, Chongqing, China
| | - Jing Gu
- Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Ming Luo
- Central Laboratory, Chongqing Public Health Medical Center, Chongqing, China
| | - Jiaoyu Deng
- Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Yaokai Chen
- Central Laboratory, Chongqing Public Health Medical Center, Chongqing, China
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13
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Vallejos-Sánchez K, Lopez JM, Antiparra R, Toscano E, Saavedra H, Kirwan DE, Amzel LM, Gilman RH, Maruenda H, Sheen P, Zimic M. Mycobacterium tuberculosis ribosomal protein S1 (RpsA) and variants with truncated C-terminal end show absence of interaction with pyrazinoic acid. Sci Rep 2020; 10:8356. [PMID: 32433489 PMCID: PMC7239899 DOI: 10.1038/s41598-020-65173-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 04/29/2020] [Indexed: 01/31/2023] Open
Abstract
Pyrazinamide (PZA) is an antibiotic used in first- and second-line tuberculosis treatment regimens. Approximately 50% of multidrug-resistant tuberculosis and over 90% of extensively drug-resistant tuberculosis strains are also PZA resistant. Despite the key role played by PZA, its mechanisms of action are not yet fully understood. It has been postulated that pyrazinoic acid (POA), the hydrolyzed product of PZA, could inhibit trans-translation by binding to Ribosomal protein S1 (RpsA) and competing with tmRNA, the natural cofactor of RpsA. Subsequent data, however, indicate that these early findings resulted from experimental artifact. Hence, in this study we assess the capacity of POA to compete with tmRNA for RpsA. We evaluated RpsA wild type (WT), RpsA ∆A438, and RpsA ∆A438 variants with truncations towards the carboxy terminal end. Interactions were measured using Nuclear Magnetic Resonance spectroscopy (NMR), Isothermal Titration Calorimetry (ITC), Microscale Thermophoresis (MST), and Electrophoretic Mobility Shift Assay (EMSA). We found no measurable binding between POA and RpsA (WT or variants). This suggests that RpsA may not be involved in the mechanism of action of PZA in Mycobacterium tuberculosis, as previously thought. Interactions observed between tmRNA and RpsA WT, RpsA ∆A438, and each of the truncated variants of RpsA ∆A438, are reported.
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Affiliation(s)
- Katherine Vallejos-Sánchez
- Laboratorio de Bioinformática, Biología Molecular y Desarrollos Tecnológicos. Laboratorios de Investigación y Desarrollo. Facultad de Ciencias y Filosofía. Universidad Peruana Cayetano Heredia, Lima, Perú
| | - Juan M Lopez
- Pontificia Universidad Católica del Perú, Departamento de Ciencias, Sección Química, Centro de Espectroscopía de Resonancia Magnética Nuclear (CERMN), Lima, Perú
| | - Ricardo Antiparra
- Laboratorio de Bioinformática, Biología Molecular y Desarrollos Tecnológicos. Laboratorios de Investigación y Desarrollo. Facultad de Ciencias y Filosofía. Universidad Peruana Cayetano Heredia, Lima, Perú
| | - Emily Toscano
- Laboratorio de Bioinformática, Biología Molecular y Desarrollos Tecnológicos. Laboratorios de Investigación y Desarrollo. Facultad de Ciencias y Filosofía. Universidad Peruana Cayetano Heredia, Lima, Perú
| | - Harry Saavedra
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD., USA
| | - Daniela E Kirwan
- Infection and Immunity Research Institute, St George's, University of London, London, England
| | - L M Amzel
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD., USA
| | - R H Gilman
- International Health Department. Johns Hopkins School of Public Health, Baltimore, MD, USA
| | - Helena Maruenda
- Pontificia Universidad Católica del Perú, Departamento de Ciencias, Sección Química, Centro de Espectroscopía de Resonancia Magnética Nuclear (CERMN), Lima, Perú
| | - Patricia Sheen
- Laboratorio de Bioinformática, Biología Molecular y Desarrollos Tecnológicos. Laboratorios de Investigación y Desarrollo. Facultad de Ciencias y Filosofía. Universidad Peruana Cayetano Heredia, Lima, Perú
| | - Mirko Zimic
- Laboratorio de Bioinformática, Biología Molecular y Desarrollos Tecnológicos. Laboratorios de Investigación y Desarrollo. Facultad de Ciencias y Filosofía. Universidad Peruana Cayetano Heredia, Lima, Perú.
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14
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Płociński P, Macios M, Houghton J, Niemiec E, Płocińska R, Brzostek A, Słomka M, Dziadek J, Young D, Dziembowski A. Proteomic and transcriptomic experiments reveal an essential role of RNA degradosome complexes in shaping the transcriptome of Mycobacterium tuberculosis. Nucleic Acids Res 2019; 47:5892-5905. [PMID: 30957850 PMCID: PMC6582357 DOI: 10.1093/nar/gkz251] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 03/25/2019] [Accepted: 04/02/2019] [Indexed: 12/28/2022] Open
Abstract
The phenotypic adjustments of Mycobacterium tuberculosis are commonly inferred from the analysis of transcript abundance. While mechanisms of transcriptional regulation have been extensively analysed in mycobacteria, little is known about mechanisms that shape the transcriptome by regulating RNA decay rates. The aim of the present study is to identify the core components of the RNA degradosome of M. tuberculosis and to analyse their function in RNA metabolism. Using an approach involving cross-linking to 4-thiouridine-labelled RNA, we mapped the mycobacterial RNA-bound proteome and identified degradosome-related enzymes polynucleotide phosphorylase (PNPase), ATP-dependent RNA helicase (RhlE), ribonuclease E (RNase E) and ribonuclease J (RNase J) as major components. We then carried out affinity purification of eGFP-tagged recombinant constructs to identify protein-protein interactions. This identified further interactions with cold-shock proteins and novel KH-domain proteins. Engineering and transcriptional profiling of strains with a reduced level of expression of core degradosome ribonucleases provided evidence of important pleiotropic roles of the enzymes in mycobacterial RNA metabolism highlighting their potential vulnerability as drug targets.
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Affiliation(s)
- Przemysław Płociński
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5A, Warsaw 02-106, Poland.,Mill Hill Laboratory, Francis Crick Institute, The Ridgeway, Mill Hill, London NW7 1AA, UK.,Institute of Medical Biology, Polish Academy of Sciences, Lodowa 106, Łódź 93-232, Poland
| | - Maria Macios
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5A, Warsaw 02-106, Poland
| | - Joanna Houghton
- Mill Hill Laboratory, Francis Crick Institute, The Ridgeway, Mill Hill, London NW7 1AA, UK
| | - Emilia Niemiec
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5A, Warsaw 02-106, Poland
| | - Renata Płocińska
- Institute of Medical Biology, Polish Academy of Sciences, Lodowa 106, Łódź 93-232, Poland
| | - Anna Brzostek
- Institute of Medical Biology, Polish Academy of Sciences, Lodowa 106, Łódź 93-232, Poland
| | - Marcin Słomka
- Biobank Lab, Department of Molecular Biophysics, Faculty of Biology and Environmental Protection, University of Łódź, Pilarskiego 14/16, Łódź 90-231, Poland
| | - Jarosław Dziadek
- Institute of Medical Biology, Polish Academy of Sciences, Lodowa 106, Łódź 93-232, Poland
| | - Douglas Young
- Mill Hill Laboratory, Francis Crick Institute, The Ridgeway, Mill Hill, London NW7 1AA, UK
| | - Andrzej Dziembowski
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5A, Warsaw 02-106, Poland.,Institute of Genetics and Biotechnology, University of Warsaw, Pawińskiego 5A, Warsaw 02-106, Poland
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15
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Del Portillo P, García-Morales L, Menéndez MC, Anzola JM, Rodríguez JG, Helguera-Repetto AC, Ares MA, Prados-Rosales R, Gonzalez-y-Merchand JA, García MJ. Hypoxia Is Not a Main Stress When Mycobacterium tuberculosis Is in a Dormancy-Like Long-Chain Fatty Acid Environment. Front Cell Infect Microbiol 2019; 8:449. [PMID: 30687646 PMCID: PMC6333855 DOI: 10.3389/fcimb.2018.00449] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Accepted: 12/18/2018] [Indexed: 12/12/2022] Open
Abstract
The capacity of Mycobacterium tuberculosis (Mtb) to sense, respond and adapt to a variable and hostile environment within the host makes it one of the most successful human pathogens. During different stages of infection, Mtb is surrounded by a plethora of lipid molecules and current evidence points out the relevance of fatty acids during the infectious process. In this study, we have compared the transcriptional response of Mtb to hypoxia in cultures supplemented with a mix of even long-chain fatty acids or dextrose as main carbon sources. Using RNA sequencing, we have identified differential expressed genes in early and late hypoxia, defined according to the in vitro Wayne and Hayes model, and compared the results with the exponential phase of growth in both carbon sources. We show that the number of genes over-expressed in the lipid medium was quite low in both, early and late hypoxia, relative to conditions including dextrose, with the exception of transcripts of stable and non-coding RNAs, which were more expressed in the fatty acid medium. We found that sigB and sigE were over-expressed in the early phase of hypoxia, confirming their pivotal role in early adaptation to low oxygen concentration independently of the carbon source. A drastic contrast was found with the transcriptional regulatory factors at early hypoxia. Only 2 transcriptional factors were over-expressed in early hypoxia in the lipid medium compared to 37 that were over-expressed in the dextrose medium. Instead of Rv0081, known to be the central regulator of hypoxia in dextrose, Rv2745c (ClgR), seems to play a main role in hypoxia in the fatty acid medium. The low level of genes associated to the stress-response during their adaptation to hypoxia in fatty acids, suggests that this lipid environment makes hypoxia a less stressful condition for the tubercle bacilli. Taken all together, these results indicate that the presence of lipid molecules shapes the metabolic response of Mtb to an adaptive state for different stresses within the host, including hypoxia. This fact could explain the success of Mtb to establish long-term survival during latent infection.
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Affiliation(s)
- Patricia Del Portillo
- Departamento de Biotecnología Molecular y Biología Computacional y Bioinformática, Corporación CorpoGen, Bogotá, Colombia
| | - Lázaro García-Morales
- Departamento de Biomedicina Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV), Ciudad de México, Mexico
| | - María Carmen Menéndez
- Departamento de Medicina Preventiva, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain
| | - Juan Manuel Anzola
- Departamento de Biotecnología Molecular y Biología Computacional y Bioinformática, Corporación CorpoGen, Bogotá, Colombia
| | - Juan Germán Rodríguez
- Departamento de Biotecnología Molecular y Biología Computacional y Bioinformática, Corporación CorpoGen, Bogotá, Colombia
| | - Addy Cecilia Helguera-Repetto
- Departamento de Inmunobioquímica, Torre de Investigación, Instituto Nacional de Perinatología Isidro Espinosa de los Reyes, Ciudad de México, Mexico
| | - Miguel A. Ares
- Unidad de Investigación Médica en Enfermedades Infecciosas y Parasitarias, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Ciudad de México, Mexico
| | - Rafael Prados-Rosales
- Departamento de Medicina Preventiva, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain
- Center for Cooperative Research bioGUNE (CICbioGUNE), Bizkaia Technology Park, Derio, Spain
| | - Jorge A. Gonzalez-y-Merchand
- Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Ciudad de México, Mexico
| | - María Jesús García
- Departamento de Medicina Preventiva, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain
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16
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Mishra S, Ahmed T, Tyagi A, Shi J, Bhushan S. Structures of Mycobacterium smegmatis 70S ribosomes in complex with HPF, tmRNA, and P-tRNA. Sci Rep 2018; 8:13587. [PMID: 30206241 PMCID: PMC6133939 DOI: 10.1038/s41598-018-31850-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Accepted: 08/23/2018] [Indexed: 11/09/2022] Open
Abstract
Ribosomes are the dynamic protein synthesis machineries of the cell. They may exist in different functional states in the cell. Therefore, it is essential to have structural information on these different functional states of ribosomes to understand their mechanism of action. Here, we present single particle cryo-EM reconstructions of the Mycobacterium smegmatis 70S ribosomes in the hibernating state (with HPF), trans-translating state (with tmRNA), and the P/P state (with P-tRNA) resolved to 4.1, 12.5, and 3.4 Å, respectively. A comparison of the P/P state with the hibernating state provides possible functional insights about the Mycobacteria-specific helix H54a rRNA segment. Interestingly, densities for all the four OB domains of bS1 protein is visible in the hibernating 70S ribosome displaying the molecular details of bS1-70S interactions. Our structural data shows a Mycobacteria-specific H54a-bS1 interaction which seems to prevent subunit dissociation and degradation during hibernation without the formation of 100S dimer. This indicates a new role of bS1 protein in 70S protection during hibernation in Mycobacteria in addition to its conserved function during translation initiation.
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MESH Headings
- Binding Sites
- Cryoelectron Microscopy
- Models, Molecular
- Mycobacterium smegmatis/genetics
- Mycobacterium smegmatis/metabolism
- Mycobacterium smegmatis/ultrastructure
- Nucleic Acid Conformation
- Protein Binding
- Protein Biosynthesis
- Protein Conformation, alpha-Helical
- Protein Conformation, beta-Strand
- Protein Interaction Domains and Motifs
- RNA, Bacterial/chemistry
- RNA, Bacterial/genetics
- RNA, Bacterial/metabolism
- RNA, Ribosomal/chemistry
- RNA, Ribosomal/genetics
- RNA, Ribosomal/metabolism
- RNA, Transfer/chemistry
- RNA, Transfer/genetics
- RNA, Transfer/metabolism
- Ribosomal Proteins/chemistry
- Ribosomal Proteins/genetics
- Ribosomal Proteins/metabolism
- Ribosomes/genetics
- Ribosomes/metabolism
- Ribosomes/ultrastructure
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Affiliation(s)
- Satabdi Mishra
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Tofayel Ahmed
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Anu Tyagi
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Jian Shi
- Center for BioImaging Sciences, National University of Singapore, Singapore, Singapore
| | - Shashi Bhushan
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore.
- NTU Institute of Structural Biology, Nanyang Technological University, Singapore, Singapore.
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17
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Liu P, Huang D, Hu X, Tang Y, Ma X, Yan R, Han Q, Guo J, Zhang Y, Sun Q, Liu Z. Targeting Inhibition of SmpB by Peptide Aptamer Attenuates the Virulence to Protect Zebrafish against Aeromonas veronii Infection. Front Microbiol 2017; 8:1766. [PMID: 28955325 PMCID: PMC5601406 DOI: 10.3389/fmicb.2017.01766] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2017] [Accepted: 08/31/2017] [Indexed: 11/21/2022] Open
Abstract
Aeromonas veronii is an important pathogen of aquatic animals, wherein Small protein B (SmpB) is required for pathogenesis by functioning as both a component in stalled-ribosome rescue and a transcription factor in upregulation of virulence gene bvgS expression. Here a specific peptide aptamer PA-1 was selected from peptide aptamer library by bacterial two-hybrid system employing pBT-SmpB as bait. The binding affinity between SmpB and PA-1 was evaluated using enzyme-linked immunosorbent assay. The key amino acids of SmpB that interact with PA-1 were identified. After PA-1 was introduced into A. veronii, the engineered strain designated as A. veronii (pN-PA-1) was more sensitive and grew slower under salt stress in comparison with wild type, as the disruption of SmpB by PA-1 resulted in significant transcription reductions of virulence-related genes. Consistent with these observations, A. veronii (pN-PA-1) was severely attenuated in model organism zebrafish, and vaccination of zebrafish with A. veronii (pN-PA-1) induced a strong antibody response. The vaccinated zebrafish were well protected against subsequent lethal challenges with virulent parental strain. Collectively, we propose that targeting inhibition of SmpB by peptide aptamer PA-1 possesses the desired qualities for a live attenuated vaccine against pathogenic A. veronii.
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Affiliation(s)
- Peng Liu
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Biological Sciences, Hainan UniversityHaikou, China
| | - Dongyi Huang
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Biological Sciences, Hainan UniversityHaikou, China
| | - Xinwen Hu
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Biological Sciences, Hainan UniversityHaikou, China
| | - Yanqiong Tang
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Biological Sciences, Hainan UniversityHaikou, China
| | - Xiang Ma
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Biological Sciences, Hainan UniversityHaikou, China
| | - Rihui Yan
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Biological Sciences, Hainan UniversityHaikou, China
| | - Qian Han
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Biological Sciences, Hainan UniversityHaikou, China
| | - Jianchun Guo
- Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural SciencesHaikou, China
| | - Yueling Zhang
- Department of Biology, College of Science, Shantou UniversityShantou, China
| | - Qun Sun
- Department of Biotechnology, College of Life Sciences, Sichuan UniversityChengdu, China
| | - Zhu Liu
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Biological Sciences, Hainan UniversityHaikou, China
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18
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Alumasa JN, Manzanillo PS, Peterson ND, Lundrigan T, Baughn AD, Cox JS, Keiler KC. Ribosome Rescue Inhibitors Kill Actively Growing and Nonreplicating Persister Mycobacterium tuberculosis Cells. ACS Infect Dis 2017; 3:634-644. [PMID: 28762275 PMCID: PMC5594445 DOI: 10.1021/acsinfecdis.7b00028] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
![]()
The
emergence of Mycobacterium tuberculosis (MTB) strains
that are resistant to most or all available antibiotics has created
a severe problem for treating tuberculosis and has spurred a quest
for new antibiotic targets. Here, we demonstrate that trans-translation is essential for growth of MTB and is a viable target
for development of antituberculosis drugs. We also show that an inhibitor
of trans-translation, KKL-35, is bactericidal against
MTB under both aerobic and anoxic conditions. Biochemical experiments
show that this compound targets helix 89 of the 23S rRNA. In silico molecular docking predicts a binding pocket for
KKL-35 adjacent to the peptidyl-transfer center in a region not targeted
by conventional antibiotics. Computational solvent mapping suggests
that this pocket is a druggable hot spot for small molecule binding.
Collectively, our findings reveal a new target for antituberculosis
drug development and provide critical insight on the mechanism of
antibacterial action for KKL-35 and related 1,3,4-oxadiazole benzamides.
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Affiliation(s)
- John N. Alumasa
- Department of Biochemistry
and Molecular Biology, The Pennsylvania State University, 401 Althouse Laboratory, University Park, Pennsylvania 16802, United States
| | - Paolo S. Manzanillo
- Department
of Molecular and Cell Biology, University of California, Berkeley, #3370, 375E Li Ka Shing Center, Berkeley, California 94720, United States
| | - Nicholas D. Peterson
- Department of Microbiology and Immunology,
Microbiology Research Facility, University of Minnesota, Rm4-115, 689 23rd Ave. SE, Minneapolis, Minnesota 55455, United States
| | - Tricia Lundrigan
- Department
of Molecular and Cell Biology, University of California, Berkeley, #3370, 375E Li Ka Shing Center, Berkeley, California 94720, United States
| | - Anthony D. Baughn
- Department of Microbiology and Immunology,
Microbiology Research Facility, University of Minnesota, Rm4-115, 689 23rd Ave. SE, Minneapolis, Minnesota 55455, United States
| | - Jeffery S. Cox
- Department
of Molecular and Cell Biology, University of California, Berkeley, #3370, 375E Li Ka Shing Center, Berkeley, California 94720, United States
| | - Kenneth C. Keiler
- Department of Biochemistry
and Molecular Biology, The Pennsylvania State University, 401 Althouse Laboratory, University Park, Pennsylvania 16802, United States
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19
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Dillon NA, Peterson ND, Feaga HA, Keiler KC, Baughn AD. Anti-tubercular Activity of Pyrazinamide is Independent of trans-Translation and RpsA. Sci Rep 2017; 7:6135. [PMID: 28733601 PMCID: PMC5522395 DOI: 10.1038/s41598-017-06415-5] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Accepted: 05/24/2017] [Indexed: 12/22/2022] Open
Abstract
Pyrazinamide (PZA) is a first line anti-tubercular drug for which the mechanism of action remains unresolved. Recently, it was proposed that the active form of PZA, pyrazinoic acid (POA), disrupts the ribosome rescue process of trans-translation in Mycobacterium tuberculosis. This model suggested that POA binds within the carboxy-terminal domain of ribosomal protein S1 (RpsA) and inhibits trans-translation leading to accumulation of stalled ribosomes. Here, we demonstrate that M. tuberculosis RpsA interacts with single stranded RNA, but not with POA. Further, we show that an rpsA polymorphism previously identified in a PZA resistant strain does not confer PZA resistance when reconstructed in a laboratory strain. Finally, by utilizing an in vitro trans-translation assay with purified M. tuberculosis ribosomes we find that an interfering oligonucleotide can inhibit trans-translation, yet POA does not inhibit trans-translation. Based on these findings, we conclude that the action of PZA is entirely independent of RpsA and trans-translation in M. tuberculosis.
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Affiliation(s)
- Nicholas A Dillon
- Department of Microbiology and Immunology, University of Minnesota Medical School, Minneapolis, MN, 55455, USA
| | - Nicholas D Peterson
- Department of Microbiology and Immunology, University of Minnesota Medical School, Minneapolis, MN, 55455, USA
| | - Heather A Feaga
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Kenneth C Keiler
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Anthony D Baughn
- Department of Microbiology and Immunology, University of Minnesota Medical School, Minneapolis, MN, 55455, USA.
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20
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Njire M, Wang N, Wang B, Tan Y, Cai X, Liu Y, Mugweru J, Guo J, Hameed HMA, Tan S, Liu J, Yew WW, Nuermberger E, Lamichhane G, Liu J, Zhang T. Pyrazinoic Acid Inhibits a Bifunctional Enzyme in Mycobacterium tuberculosis. Antimicrob Agents Chemother 2017; 61:e00070-17. [PMID: 28438933 PMCID: PMC5487608 DOI: 10.1128/aac.00070-17] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Accepted: 04/01/2017] [Indexed: 11/20/2022] Open
Abstract
Pyrazinamide (PZA), an indispensable component of modern tuberculosis treatment, acts as a key sterilizing drug. While the mechanism of activation of this prodrug into pyrazinoic acid (POA) by Mycobacterium tuberculosis has been extensively studied, not all molecular determinants that confer resistance to this mysterious drug have been identified. Here, we report how a new PZA resistance determinant, the Asp67Asn substitution in Rv2783, confers M. tuberculosis resistance to PZA. Expression of the mutant allele but not the wild-type allele in M. tuberculosis recapitulates the PZA resistance observed in clinical isolates. In addition to catalyzing the metabolism of RNA and single-stranded DNA, Rv2783 also metabolized ppGpp, an important signal transducer involved in the stringent response in bacteria. All catalytic activities of the wild-type Rv2783 but not the mutant were significantly inhibited by POA. These results, which indicate that Rv2783 is a target of PZA, provide new insight into the molecular mechanism of the sterilizing activity of this drug and a basis for improving the molecular diagnosis of PZA resistance and developing evolved PZA derivatives to enhance its antituberculosis activity.
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Affiliation(s)
- Moses Njire
- State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Na Wang
- State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
- School of Life Science, University of Science and Technology of China, Hefei, China
| | - Bangxing Wang
- State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
| | - Yaoju Tan
- State Key Laboratory of Respiratory Disease, Department of Clinical Laboratory, Guangzhou Chest Hospital, Guangzhou, China
| | - Xingshan Cai
- State Key Laboratory of Respiratory Disease, Department of Clinical Laboratory, Guangzhou Chest Hospital, Guangzhou, China
| | - Yanwen Liu
- State Key Laboratory of Respiratory Disease, Department of Clinical Laboratory, Guangzhou Chest Hospital, Guangzhou, China
| | - Julius Mugweru
- State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Jintao Guo
- State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
| | - H M Adnan Hameed
- State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Shouyong Tan
- State Key Laboratory of Respiratory Disease, Department of Clinical Laboratory, Guangzhou Chest Hospital, Guangzhou, China
| | - Jianxiong Liu
- State Key Laboratory of Respiratory Disease, Department of Clinical Laboratory, Guangzhou Chest Hospital, Guangzhou, China
| | - Wing Wai Yew
- Stanley Ho Centre for Emerging Infectious Diseases, the Chinese University of Hong Kong, Hong Kong, China
| | - Eric Nuermberger
- Center for Tuberculosis Research, Department of Medicine, Johns Hopkins University, Baltimore, Maryland, USA
| | - Gyanu Lamichhane
- Center for Tuberculosis Research, Department of Medicine, Johns Hopkins University, Baltimore, Maryland, USA
| | - Jinsong Liu
- State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Tianyu Zhang
- State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
- University of Chinese Academy of Sciences, Beijing, China
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Long-Chain Fatty Acyl Coenzyme A Ligase FadD2 Mediates Intrinsic Pyrazinamide Resistance in Mycobacterium tuberculosis. Antimicrob Agents Chemother 2017; 61:AAC.02130-16. [PMID: 27855077 DOI: 10.1128/aac.02130-16] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Accepted: 10/29/2016] [Indexed: 11/20/2022] Open
Abstract
Pyrazinamide (PZA) is a first-line tuberculosis (TB) drug that has been in clinical use for 60 years yet still has an unresolved mechanism of action. Based upon the observation that the minimum concentration of PZA required to inhibit the growth of Mycobacterium tuberculosis is approximately 1,000-fold higher than that of other first-line drugs, we hypothesized that M. tuberculosis expresses factors that mediate intrinsic resistance to PZA. To identify genes associated with intrinsic PZA resistance, a library of transposon-mutagenized Mycobacterium bovis BCG strains was screened for strains showing hypersusceptibility to the active form of PZA, pyrazinoic acid (POA). Disruption of the long-chain fatty acyl coenzyme A (CoA) ligase FadD2 enhanced POA susceptibility by 16-fold on agar medium, and the wild-type level of susceptibility was restored upon expression of fadD2 from an integrating mycobacterial vector. Consistent with the recent observation that POA perturbs mycobacterial CoA metabolism, the fadD2 mutant strain was more vulnerable to POA-mediated CoA depletion than the wild-type strain. Ectopic expression of the M. tuberculosis pyrazinamidase PncA, necessary for conversion of PZA to POA, in the fadD2 transposon insertion mutant conferred at least a 16-fold increase in PZA susceptibility under active growth conditions in liquid culture at neutral pH. Importantly, deletion of fadD2 in M. tuberculosis strain H37Rv also resulted in enhanced susceptibility to POA. These results indicate that FadD2 is associated with intrinsic PZA and POA resistance and provide a proof of concept for the target-based potentiation of PZA activity in M. tuberculosis.
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Colameco S, Elliot MA. Non-coding RNAs as antibiotic targets. Biochem Pharmacol 2016; 133:29-42. [PMID: 28012959 DOI: 10.1016/j.bcp.2016.12.015] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Accepted: 12/12/2016] [Indexed: 02/07/2023]
Abstract
Antibiotics inhibit a wide range of essential processes in the bacterial cell, including replication, transcription, translation and cell wall synthesis. In many instances, these antibiotics exert their effects through association with non-coding RNAs. This review highlights many classical antibiotic targets (e.g. rRNAs and the ribosome), explores a number of emerging targets (e.g. tRNAs, RNase P, riboswitches and small RNAs), and discusses the future directions and challenges associated with non-coding RNAs as antibiotic targets.
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Affiliation(s)
- Savannah Colameco
- Department of Biology and Institute for Infectious Disease Research, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4K1, Canada
| | - Marie A Elliot
- Department of Biology and Institute for Infectious Disease Research, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4K1, Canada.
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23
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Trans-translation is essential in the human pathogen Legionella pneumophila. Sci Rep 2016; 6:37935. [PMID: 27892503 PMCID: PMC5124942 DOI: 10.1038/srep37935] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Accepted: 11/02/2016] [Indexed: 11/09/2022] Open
Abstract
Trans-translation is a ubiquitous bacterial mechanism for ribosome rescue in the event of translation stalling. Although trans-translation is not essential in several bacterial species, it has been found essential for viability or virulence in a wide range of pathogens. We describe here that trans-translation is essential in the human pathogen Legionella pneumophila, the etiologic agent of Legionnaire's disease (LD), a severe form of nosocomial and community-acquired pneumonia. The ssrA gene coding for tmRNA, the key component of trans-translation, could not be deleted in L. pneumophila. To circumvent this and analyse the consequences of impaired trans-translation, we placed ssrA under the control of a chemical inducer. Phenotypes associated with the inhibition of ssrA expression include growth arrest in rich medium, hampered cell division, and hindered ability to infect eukaryotic cells (amoebae and human macrophages). LD is often associated with failure of antibiotic treatment and death (>10% of clinical cases). Decreasing tmRNA levels led to significantly higher sensitivity to ribosome-targeting antibiotics, including to erythromycin. We also detected a higher sensitivity to the transcription inhibitor rifampicin. Both antibiotics are recommended treatments for LD. Thus, interfering with trans-translation may not only halt the infection, but could also potentiate the recommended therapeutic treatments of LD.
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Liu P, Chen Y, Wang D, Tang Y, Tang H, Song H, Sun Q, Zhang Y, Liu Z. Genetic Selection of Peptide Aptamers That Interact and Inhibit Both Small Protein B and Alternative Ribosome-Rescue Factor A of Aeromonas veronii C4. Front Microbiol 2016; 7:1228. [PMID: 27588015 PMCID: PMC4988972 DOI: 10.3389/fmicb.2016.01228] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Accepted: 07/22/2016] [Indexed: 12/29/2022] Open
Abstract
Aeromonas veronii is a pathogenic gram-negative bacterium, which infects a variety of animals and results in mass mortality. The stalled-ribosome rescues are reported to ensure viability and virulence under stress conditions, of which primarily include trans-translation and alternative ribosome-rescue factor A (ArfA) in A. veronii. For identification of specific peptides that interact and inhibit the stalled-ribosome rescues, peptide aptamer library (pTRG-SN-peptides) was constructed using pTRG as vector and Staphylococcus aureus nuclease (SN) as scaffold protein, in which 16 random amino acids were introduced to form an exposed surface loop. In the meantime both Small Protein B (SmpB) which acts as one of the key components in trans-translation, and ArfA were inserted to pBT to constitute pBT-SmpB and pBT-ArfA, respectively. The peptide aptamer PA-2 was selected from pTRG-SN-peptides by bacterial two-hybrid system (B2H) employing pBT-SmpB or pBT-ArfA as baits. The conserved sites G133K134 and D138K139R140 of C-terminal SmpB were identified by interacting with N-terminal SN, and concurrently the residue K62 of ArfA was recognized by interacting with the surface loop of the specific peptide aptamer PA-2. The expression plasmids pN-SN or pN-PA-2, which combined the duplication origin of pRE112 with the neokanamycin promoter expressing SN or PA-2, were created and transformed into A. veronii C4, separately. The engineered A. veronii C4 which endowing SN or PA-2 expression impaired growth capabilities under stress conditions including temperatures, sucrose, glucose, potassium chloride (KCl) and antibiotics, and the stress-related genes rpoS and nhaP were down-regulated significantly by Quantitative Real-time PCR (qRT-PCR) when treating in 2.0% KCl. Thus, the engineered A. veronii C4 conferring PA-2 expression might be potentially attenuated vaccine, and also the peptide aptamer PA-2 could develop as anti-microbial drugs targeted to the ribosome rescued factors in A. veronii.
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Affiliation(s)
- Peng Liu
- Department of Biology, College of Sciences, Shantou University Shantou, China
| | - Yong Chen
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Agriculture, Hainan University Haikou, China
| | - Dan Wang
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Agriculture, Hainan University Haikou, China
| | - Yanqiong Tang
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Agriculture, Hainan University Haikou, China
| | - Hongqian Tang
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Agriculture, Hainan University Haikou, China
| | - Haichao Song
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Agriculture, Hainan University Haikou, China
| | - Qun Sun
- Department of Biotechnology, College of Life Sciences, Sichuan University Chengdu, China
| | - Yueling Zhang
- Department of Biology, College of Sciences, Shantou University Shantou, China
| | - Zhu Liu
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Agriculture, Hainan University Haikou, China
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26
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Miotto P, Cirillo DM, Migliori GB. Drug resistance in Mycobacterium tuberculosis: molecular mechanisms challenging fluoroquinolones and pyrazinamide effectiveness. Chest 2015; 147:1135-1143. [PMID: 25846529 DOI: 10.1378/chest.14-1286] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Physicians are more and more often challenged by difficult-to-treat cases of TB. They include patients infected by strains of Mycobacterium tuberculosis that are resistant to at least isoniazid and rifampicin (multidrug-resistant TB) or to at least one fluoroquinolone (FQ) and one injectable, second-line anti-TB drug in addition to isoniazid and rifampicin (extensively drug-resistant TB). The drug treatment of these cases is very long, toxic, and expensive, and, unfortunately, the proportion of unsatisfactory outcomes is still considerably high. Although FQs and pyrazinamide (PZA) are backbone drugs in the available anti-TB regimens, several uncertainties remain about their mechanisms of action and even more remain about the mechanisms leading to drug resistance. From a clinical point of view, a better understanding of the genetic basis of drug resistance will aid (1) clinicians to provide quality clinical management to both drug-susceptible and drug-resistant TB cases (while preventing emergence of further resistance), and (2) developers of new molecular-based diagnostic assays to better direct their research efforts toward a new generation of sensitive, specific, cheap, and easy-to-use point-of-care diagnostics. In this review we provide an update on the molecular mechanisms leading to FQ- and PZA-resistance in M tuberculosis.
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Affiliation(s)
- Paolo Miotto
- Emerging Bacterial Pathogens Unit, Division of Immunology, Transplantation and Infectious Diseases, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Daniela M Cirillo
- Emerging Bacterial Pathogens Unit, Division of Immunology, Transplantation and Infectious Diseases, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Giovanni Battista Migliori
- WHO Collaborating Centre for TB and Lung Diseases, Fondazione S. Maugeri, Care and Research Institute, Tradate, Italy.
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Pantothenate and pantetheine antagonize the antitubercular activity of pyrazinamide. Antimicrob Agents Chemother 2014; 58:7258-63. [PMID: 25246400 DOI: 10.1128/aac.04028-14] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pyrazinamide (PZA) is a first-line tuberculosis drug that inhibits the growth of Mycobacterium tuberculosis via an as yet undefined mechanism. An M. tuberculosis laboratory strain that was auxotrophic for pantothenate was found to be insensitive to PZA and to the active form, pyrazinoic acid (POA). To determine whether this phenotype was strain or condition specific, the effect of pantothenate supplementation on PZA activity was assessed using prototrophic strains of M. tuberculosis. It was found that pantothenate and other β-alanine-containing metabolites abolished PZA and POA susceptibility, suggesting that POA might selectively target pantothenate synthesis. However, when the pantothenate-auxotrophic strain was cultivated using a subantagonistic concentration of pantetheine in lieu of pantothenate, susceptibility to PZA and POA was restored. In addition, we found that β-alanine could not antagonize PZA and POA activity against the pantothenate-auxotrophic strain, indicating that the antagonism is specific to pantothenate. Moreover, pantothenate-mediated antagonism was observed for structurally related compounds, including n-propyl pyrazinoate, 5-chloropyrazinamide, and nicotinamide, but not for nicotinic acid or isoniazid. Taken together, these data demonstrate that while pantothenate can interfere with the action of PZA, pantothenate synthesis is not directly targeted by PZA. Our findings suggest that targeting of pantothenate synthesis has the potential to enhance PZA efficacy and possibly to restore PZA susceptibility in isolates with panD-linked resistance.
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29
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Wower IK, Zwieb C, Wower J. Requirements for resuming translation in chimeric transfer-messenger RNAs of Escherichia coli and Mycobacterium tuberculosis. BMC Mol Biol 2014; 15:19. [PMID: 25220282 PMCID: PMC4236655 DOI: 10.1186/1471-2199-15-19] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Accepted: 06/18/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Trans-translation is catalyzed by ribonucleprotein complexes composed of SmpB protein and transfer-messenger RNA. They release stalled ribosomes from truncated mRNAs and tag defective proteins for proteolytic degradation. Comparative sequence analysis of bacterial tmRNAs provides considerable insights into their secondary structures in which a tRNA-like domain and an mRNA-like region are connected by a variable number of pseudoknots. Progress toward understanding the molecular mechanism of trans-translation is hampered by our limited knowledge about the structure of tmRNA:SmpB complexes. RESULTS Complexes consisting of M. tuberculosis tmRNA and E. coli SmpB tag truncated proteins poorly in E. coli. In contrast, the tagging activity of E. coli tmRNA is well supported by M. tuberculosis SmpB that is expressed in E. coli. To investigate this incompatibility, we constructed 12 chimeric tmRNA molecules composed of structural features derived from both E. coli and M. tuberculosis. Our studies demonstrate that replacing the hp5-pk2-pk3-pk4 segment of E. coli tmRNA with the equivalent segment of M. tuberculosis tmRNA has no significant effect on the tagging efficiency of chimeric tmRNAs in the presence of E. coli SmpB. Replacing either helices 2b-2d, the single-stranded part of the ORF, pk1, or residues 79-89 of E. coli tmRNA with the equivalent features of M. tuberculosis tmRNA yields chimeric tmRNAs that are tagged at 68 to 88 percent of what is observed with E. coli tmRNA. Exchanging segments composed of either pk1 and the single-stranded segment upstream of the ORF or helices 2b-2d and pk1 results in markedly impaired tagging activity. CONCLUSION Our observations demonstrate the existence of functionally important but as yet uncharacterized structural constraints in the segment of tmRNA that connects its TLD to the ORF used for resuming translation. As trans-translation is important for the survival of M. tuberculosis, our work provides a new target for pharmacological intervention against multidrug-resistant tuberculosis.
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Hudson CM, Lau BY, Williams KP. Ends of the line for tmRNA-SmpB. Front Microbiol 2014; 5:421. [PMID: 25165464 PMCID: PMC4131195 DOI: 10.3389/fmicb.2014.00421] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2014] [Accepted: 07/24/2014] [Indexed: 11/22/2022] Open
Abstract
Genes for the RNA tmRNA and protein SmpB, partners in the trans-translation process that rescues stalled ribosomes, have previously been found in all bacteria and some organelles. During a major update of The tmRNA Website (relocated to http://bioinformatics.sandia.gov/tmrna), including addition of an SmpB sequence database, we found some bacteria that lack functionally significant regions of SmpB. Three groups with reduced genomes have lost the central loop of SmpB, which is thought to improve alanylation and EF-Tu activation: Carsonella, Hodgkinia, and the hemoplasmas (hemotropic Mycoplasma). Carsonella has also lost the SmpB C-terminal tail, thought to stimulate the decoding center of the ribosome. We validate recent identification of tmRNA homologs in oomycete mitochondria by finding partner genes from oomycete nuclei that target SmpB to the mitochondrion. We have moreover identified through exhaustive search a small number of complete, but often highly derived, bacterial genomes that appear to lack a functional copy of either the tmRNA or SmpB gene (but not both). One Carsonella isolate exhibits complete degradation of the tmRNA gene sequence yet its smpB shows no evidence for relaxed selective constraint, relative to other genes in the genome. After loss of the SmpB central loop in the hemoplasmas, one subclade apparently lost tmRNA. Carsonella also exhibits gene overlap such that tmRNA maturation should produce a non-stop smpB mRNA. At least some of the tmRNA/SmpB-deficient strains appear to further lack the ArfA and ArfB backup systems for ribosome rescue. The most frequent neighbors of smpB are the tmRNA gene, a ratA/rnfH unit, and the gene for RNaseR, a known physical and functional partner of tmRNA-SmpB.
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Affiliation(s)
- Corey M Hudson
- Sandia National Laboratories, Department of Systems Biology Livermore, CA, USA
| | - Britney Y Lau
- Sandia National Laboratories, Department of Systems Biology Livermore, CA, USA
| | - Kelly P Williams
- Sandia National Laboratories, Department of Systems Biology Livermore, CA, USA
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Abstract
Problems during gene expression can result in a ribosome that has translated to the 3' end of an mRNA without terminating at a stop codon, forming a nonstop translation complex. The nonstop translation complex contains a ribosome with the mRNA and peptidyl-tRNA engaged, but because there is no codon in the A site, the ribosome cannot elongate or terminate the nascent chain. Recent work has illuminated the importance of resolving these nonstop complexes in bacteria. Transfer-messenger RNA (tmRNA)-SmpB specifically recognizes and resolves nonstop translation complexes in a reaction known as trans-translation. trans-Translation releases the ribosome and promotes degradation of the incomplete nascent polypeptide and problematic mRNA. tmRNA and SmpB have been found in all bacteria and are essential in some species. However, other bacteria can live without trans-translation because they have one of the alternative release factors, ArfA or ArfB. ArfA recruits RF2 to nonstop translation complexes to promote hydrolysis of the peptidyl-tRNAs. ArfB recognizes nonstop translation complexes in a manner similar to tmRNA-SmpB recognition and directly hydrolyzes the peptidyl-tRNAs to release the stalled ribosomes. Genetic studies indicate that most or all species require at least one mechanism to resolve nonstop translation complexes. Consistent with such a requirement, small molecules that inhibit resolution of nonstop translation complexes have broad-spectrum antibacterial activity. These results suggest that resolving nonstop translation complexes is a matter of life or death for bacteria.
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