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Fleming BA, Blango MG, Rousek AA, Kincannon WM, Tran A, Lewis A, Russell C, Zhou Q, Baird LM, Barber A, Brannon JR, Beebout C, Bandarian V, Hadjifrangiskou M, Howard M, Mulvey M. A tRNA modifying enzyme as a tunable regulatory nexus for bacterial stress responses and virulence. Nucleic Acids Res 2022; 50:7570-7590. [PMID: 35212379 PMCID: PMC9303304 DOI: 10.1093/nar/gkac116] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 02/02/2022] [Accepted: 02/08/2022] [Indexed: 11/16/2022] Open
Abstract
Post-transcriptional modifications can impact the stability and functionality of many different classes of RNA molecules and are an especially important aspect of tRNA regulation. It is hypothesized that cells can orchestrate rapid responses to changing environmental conditions by adjusting the specific types and levels of tRNA modifications. We uncovered strong evidence in support of this tRNA global regulation hypothesis by examining effects of the well-conserved tRNA modifying enzyme MiaA in extraintestinal pathogenic Escherichia coli (ExPEC), a major cause of urinary tract and bloodstream infections. MiaA mediates the prenylation of adenosine-37 within tRNAs that decode UNN codons, and we found it to be crucial to the fitness and virulence of ExPEC. MiaA levels shifted in response to stress via a post-transcriptional mechanism, resulting in marked changes in the amounts of fully modified MiaA substrates. Both ablation and forced overproduction of MiaA stimulated translational frameshifting and profoundly altered the ExPEC proteome, with variable effects attributable to UNN content, changes in the catalytic activity of MiaA, or availability of metabolic precursors. Cumulatively, these data indicate that balanced input from MiaA is critical for optimizing cellular responses, with MiaA acting much like a rheostat that can be used to realign global protein expression patterns.
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Affiliation(s)
- Brittany A Fleming
- Division of Microbiology and Immunology, Pathology Department, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Matthew G Blango
- Junior Research Group RNA Biology of Fungal Infections, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knöll Institute (Leibniz-HKI), 07745 Jena, Germany
| | - Alexis A Rousek
- Division of Microbiology and Immunology, Pathology Department, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | | | - Alexander Tran
- Division of Microbiology and Immunology, Pathology Department, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Adam J Lewis
- Division of Microbiology and Immunology, Pathology Department, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Colin W Russell
- Division of Microbiology and Immunology, Pathology Department, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Qin Zhou
- Division of Microbiology and Immunology, Pathology Department, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Lisa M Baird
- Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA
| | - Amelia E Barber
- Division of Microbiology and Immunology, Pathology Department, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - John R Brannon
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Connor J Beebout
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Vahe Bandarian
- Department of Chemistry, University of Utah, Salt Lake City, UT 84112, USA
| | - Maria Hadjifrangiskou
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Michael T Howard
- Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA
| | - Matthew A Mulvey
- Division of Microbiology and Immunology, Pathology Department, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
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2
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Rozik P, Szabla R, Lant JT, Kiri R, Wright DE, Junop M, O'Donoghue P. A novel fluorescent reporter sensitive to serine mis-incorporation. RNA Biol 2022; 19:221-233. [PMID: 35167412 PMCID: PMC8855846 DOI: 10.1080/15476286.2021.2015173] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
High-fidelity translation was considered a requirement for living cells. The frozen accident theory suggested that any deviation from the standard genetic code should result in the production of so much mis-made and non-functional proteins that cells cannot remain viable. Studies in bacterial, yeast, and mammalian cells show that significant levels of mistranslation (1–10% per codon) can be tolerated or even beneficial under conditions of oxidative stress. Single tRNA mutants, which occur naturally in the human population, can lead to amino acid mis-incorporation at a codon or set of codons. The rate or level of mistranslation can be difficult or impossible to measure in live cells. We developed a novel red fluorescent protein reporter that is sensitive to serine (Ser) mis-incorporation at proline (Pro) codons. The mCherry Ser151Pro mutant is efficiently produced in Escherichia coli but non-fluorescent. We demonstrated in cells and with purified mCherry protein that the fluorescence of mCherry Ser151Pro is rescued by two different tRNASer gene variants that were mutated to contain the Pro (UGG) anticodon. Ser mis-incorporation was confirmed by mass spectrometry. Remarkably, E. coli tolerated mistranslation rates of ~10% per codon with negligible reduction in growth rate. Conformational sampling simulations revealed that the Ser151Pro mutant leads to significant changes in the conformational freedom of the chromophore precursor, which is indicative of a defect in chromophore maturation. Together our data suggest that the mCherry Ser151 mutants may be used to report Ser mis-incorporation at multiple other codons, further expanding the ability to measure mistranslation in living cells.
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Affiliation(s)
- Peter Rozik
- Department of Biochemistry, The University of Western Ontario, London, Ontario, Canada
| | - Robert Szabla
- Department of Biochemistry, The University of Western Ontario, London, Ontario, Canada
| | - Jeremy T Lant
- Department of Biochemistry, The University of Western Ontario, London, Ontario, Canada
| | - Rashmi Kiri
- Department of Biochemistry, The University of Western Ontario, London, Ontario, Canada
| | - David E Wright
- Department of Biochemistry, The University of Western Ontario, London, Ontario, Canada
| | - Murray Junop
- Department of Biochemistry, The University of Western Ontario, London, Ontario, Canada
| | - Patrick O'Donoghue
- Department of Biochemistry, The University of Western Ontario, London, Ontario, Canada.,Department of Chemistry, The University of Western Ontario, London, Ontario, Canada
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3
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Singh T, Yadav SK, Vainstein A, Kumar V. Genome recoding strategies to improve cellular properties: mechanisms and advances. ABIOTECH 2021; 2:79-95. [PMID: 34377578 PMCID: PMC7675020 DOI: 10.1007/s42994-020-00030-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Accepted: 10/07/2020] [Indexed: 11/10/2022]
Abstract
The genetic code, once believed to be universal and immutable, is now known to contain many variations and is not quite universal. The basis for genome recoding strategy is genetic code variation that can be harnessed to improve cellular properties. Thus, genome recoding is a promising strategy for the enhancement of genome flexibility, allowing for novel functions that are not commonly documented in the organism in its natural environment. Here, the basic concept of genetic code and associated mechanisms for the generation of genetic codon variants, including biased codon usage, codon reassignment, and ambiguous decoding, are extensively discussed. Knowledge of the concept of natural genetic code expansion is also detailed. The generation of recoded organisms and associated mechanisms with basic targeting components, including aminoacyl-tRNA synthetase-tRNA pairs, elongation factor EF-Tu and ribosomes, are highlighted for a comprehensive understanding of this concept. The research associated with the generation of diverse recoded organisms is also discussed. The success of genome recoding in diverse multicellular organisms offers a platform for expanding protein chemistry at the biochemical level with non-canonical amino acids, genetically isolating the synthetic organisms from the natural ones, and fighting viruses, including SARS-CoV2, through the creation of attenuated viruses. In conclusion, genome recoding can offer diverse applications for improving cellular properties in the genome-recoded organisms.
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Affiliation(s)
- Tanya Singh
- Department of Botany, School of Basic Sciences, Central University of Punjab, Bathinda, 151001 India
| | | | - Alexander Vainstein
- Institute of Plant Sciences and Genetics in Agriculture, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Vinay Kumar
- Department of Botany, School of Basic Sciences, Central University of Punjab, Bathinda, 151001 India
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4
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Varanda AS, Santos M, Soares AR, Vitorino R, Oliveira P, Oliveira C, Santos MAS. Human cells adapt to translational errors by modulating protein synthesis rate and protein turnover. RNA Biol 2020; 17:135-149. [PMID: 31570039 PMCID: PMC6948982 DOI: 10.1080/15476286.2019.1670039] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 09/12/2019] [Accepted: 09/14/2019] [Indexed: 02/08/2023] Open
Abstract
Deregulation of tRNAs, aminoacyl-tRNA synthetases (aaRS) or tRNA modifying enzymes, increase the level of protein synthesis errors (PSE) and are associated with several diseases, but the cause-effect mechanisms of these pathologies remain elusive. To clarify the role of PSE in human biology, we have engineered a HEK293 cell line to overexpress a wild type (Wt) tRNASer and two tRNASer mutants that misincorporate serine at non-cognate codon sites. Then, we followed long-term adaptation to PSE of such recombinant cells by analysing cell viability, protein synthesis rate and activation of protein quality control mechanisms (PQC). Engineered cells showed higher level of misfolded and aggregated proteins; activated the ubiquitin-proteasome system (UPS) and the unfolded protein response (UPR), indicative of proteotoxic stress. Adaptation to PSE involved increased protein turnover, UPR up-regulation and altered protein synthesis rate. Gene expression analysis showed that engineered cells presented recurrent alterations in the endoplasmic reticulum, cell adhesion and calcium homeostasis. Herein, we unveil new phenotypic consequences of protein synthesis errors in human cells and identify the protein quality control processes that are necessary for long-term adaptation to PSE and proteotoxic stress. Our data provide important insight on how chronic proteotoxic stress may cause disease and highlight potential biological pathways that support the association of PSE with disease.
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Affiliation(s)
- Ana Sofia Varanda
- Department of Medical Sciences and Institute of Biomedicine – iBiMED, University of Aveiro, Aveiro, Portugal
- Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP), Porto, Portugal
- Expression Regulation in Cancer, Instituto de Investigação e Inovação em Saúde (i3S), University of Porto, Porto, Portugal
| | - Mafalda Santos
- Department of Medical Sciences and Institute of Biomedicine – iBiMED, University of Aveiro, Aveiro, Portugal
- Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP), Porto, Portugal
- Expression Regulation in Cancer, Instituto de Investigação e Inovação em Saúde (i3S), University of Porto, Porto, Portugal
| | - Ana R. Soares
- Department of Medical Sciences and Institute of Biomedicine – iBiMED, University of Aveiro, Aveiro, Portugal
| | - Rui Vitorino
- Department of Medical Sciences and Institute of Biomedicine – iBiMED, University of Aveiro, Aveiro, Portugal
| | - Patrícia Oliveira
- Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP), Porto, Portugal
- Expression Regulation in Cancer, Instituto de Investigação e Inovação em Saúde (i3S), University of Porto, Porto, Portugal
| | - Carla Oliveira
- Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP), Porto, Portugal
- Expression Regulation in Cancer, Instituto de Investigação e Inovação em Saúde (i3S), University of Porto, Porto, Portugal
- Department of Pathology, Faculty of Medicine, University of Porto, Porto, Portugal
| | - Manuel A. S. Santos
- Department of Medical Sciences and Institute of Biomedicine – iBiMED, University of Aveiro, Aveiro, Portugal
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5
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Ferreira N, Perks KL, Rossetti G, Rudler DL, Hughes LA, Ermer JA, Scott LH, Kuznetsova I, Richman TR, Narayana VK, Abudulai LN, Shearwood AMJ, Cserne Szappanos H, Tull D, Yeoh GC, Hool LC, Filipovska A, Rackham O. Stress signaling and cellular proliferation reverse the effects of mitochondrial mistranslation. EMBO J 2019; 38:e102155. [PMID: 31721250 DOI: 10.15252/embj.2019102155] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 09/17/2019] [Accepted: 09/20/2019] [Indexed: 12/12/2022] Open
Abstract
Translation fidelity is crucial for prokaryotes and eukaryotic nuclear-encoded proteins; however, little is known about the role of mistranslation in mitochondria and its potential effects on metabolism. We generated yeast and mouse models with error-prone and hyper-accurate mitochondrial translation, and found that translation rate is more important than translational accuracy for cell function in mammals. Specifically, we found that mitochondrial mistranslation causes reduced overall mitochondrial translation and respiratory complex assembly rates. In mammals, this effect is compensated for by increased mitochondrial protein stability and upregulation of the citric acid cycle. Moreover, this induced mitochondrial stress signaling, which enables the recovery of mitochondrial translation via mitochondrial biogenesis, telomerase expression, and cell proliferation, and thereby normalizes metabolism. Conversely, we show that increased fidelity of mitochondrial translation reduces the rate of protein synthesis without eliciting a mitochondrial stress response. Consequently, the rate of translation cannot be recovered and this leads to dilated cardiomyopathy in mice. In summary, our findings reveal mammalian-specific signaling pathways that respond to changes in the fidelity of mitochondrial protein synthesis and affect metabolism.
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Affiliation(s)
- Nicola Ferreira
- Harry Perkins Institute of Medical Research, Nedlands, WA, Australia.,The University of Western Australia Centre for Medical Research, Crawley, WA, Australia
| | - Kara L Perks
- Harry Perkins Institute of Medical Research, Nedlands, WA, Australia.,The University of Western Australia Centre for Medical Research, Crawley, WA, Australia
| | - Giulia Rossetti
- Harry Perkins Institute of Medical Research, Nedlands, WA, Australia.,The University of Western Australia Centre for Medical Research, Crawley, WA, Australia
| | - Danielle L Rudler
- Harry Perkins Institute of Medical Research, Nedlands, WA, Australia.,The University of Western Australia Centre for Medical Research, Crawley, WA, Australia
| | - Laetitia A Hughes
- Harry Perkins Institute of Medical Research, Nedlands, WA, Australia.,The University of Western Australia Centre for Medical Research, Crawley, WA, Australia
| | - Judith A Ermer
- Harry Perkins Institute of Medical Research, Nedlands, WA, Australia.,The University of Western Australia Centre for Medical Research, Crawley, WA, Australia
| | - Louis H Scott
- Harry Perkins Institute of Medical Research, Nedlands, WA, Australia.,The University of Western Australia Centre for Medical Research, Crawley, WA, Australia
| | - Irina Kuznetsova
- Harry Perkins Institute of Medical Research, Nedlands, WA, Australia.,The University of Western Australia Centre for Medical Research, Crawley, WA, Australia
| | - Tara R Richman
- Harry Perkins Institute of Medical Research, Nedlands, WA, Australia.,The University of Western Australia Centre for Medical Research, Crawley, WA, Australia
| | - Vinod K Narayana
- Metabolomics Australia, Bio21 Institute of Molecular Science and Biotechnology, University of Melbourne, Parkville, Vic., Australia
| | - Laila N Abudulai
- Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, Perth, WA, Australia.,School of Molecular Sciences, The University of Western Australia, Crawley, WA, Australia.,The School of Biomedical Sciences, The University of Western Australia, Nedlands, WA, Australia
| | - Anne-Marie J Shearwood
- Harry Perkins Institute of Medical Research, Nedlands, WA, Australia.,The University of Western Australia Centre for Medical Research, Crawley, WA, Australia
| | | | - Dedreia Tull
- Metabolomics Australia, Bio21 Institute of Molecular Science and Biotechnology, University of Melbourne, Parkville, Vic., Australia
| | - George C Yeoh
- Harry Perkins Institute of Medical Research, Nedlands, WA, Australia
| | - Livia C Hool
- School of Human Sciences (Physiology), The University of Western Australia, Crawley, WA, Australia.,Victor Chang Cardiac Research Institute, Darlinghurst, NSW, Australia
| | - Aleksandra Filipovska
- Harry Perkins Institute of Medical Research, Nedlands, WA, Australia.,The University of Western Australia Centre for Medical Research, Crawley, WA, Australia.,School of Molecular Sciences, The University of Western Australia, Crawley, WA, Australia
| | - Oliver Rackham
- Harry Perkins Institute of Medical Research, Nedlands, WA, Australia.,School of Pharmacy and Biomedical Sciences, Curtin University, Bentley, WA, Australia.,Curtin Health Innovation Research Institute, Curtin University, Bentley, WA, Australia
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6
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Barbieri M. Evolution of the genetic code: The ambiguity-reduction theory. Biosystems 2019; 185:104024. [DOI: 10.1016/j.biosystems.2019.104024] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Revised: 08/26/2019] [Accepted: 08/26/2019] [Indexed: 10/26/2022]
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7
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Ubiquitinated Proteins Isolated From Tumor Cells Are Efficient Substrates for Antigen Cross-Presentation. J Immunother 2018; 40:155-163. [PMID: 28368960 DOI: 10.1097/cji.0000000000000165] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
We have previously shown that inhibition of the proteasome causes defective ribosomal products to be shunted into autophagosomes and subsequently released from tumor cells as defective ribosomal products in Blebs (DRibbles). These DRibbles serve as an excellent source of antigens for cross-priming of tumor-specific T cells. Here, we examine the role of ubiquitinated proteins (Ub-proteins) in this pathway. Using purified Ub-proteins from tumor cells that express endogenous tumor-associated antigen or exogenous viral antigen, we tested the ability of these proteins to stimulate antigen-specific T-cell responses, by activation of monocyte-derived dendritic cells generated from human peripheral blood mononuclear cells. Compared with total cell lysates, we found that purified Ub-proteins from both a gp100-specific melanoma cell line and from a lung cancer cell line expressing cytomegalovirus pp65 antigen produced a significantly higher level of IFN-γ in gp100- or pp65-specific T cells, respectively. In addition, Ub-proteins from an allogeneic tumor cell line could be used to stimulate tumor-infiltrating lymphocytes isolated and expanded from non-small cell lung cancer patients. These results establish that Ub-proteins provide a relevant source of antigens for cross-priming of antitumor immune responses in a variety of settings, including endogenous melanoma and exogenous viral antigen presentation, as well as antigen-specific tumor-infiltrating lymphocytes. Thus, ubiquitin can be used as an affinity tag to enrich for unknown tumor-specific antigens from tumor cell lysates to stimulate tumor-specific T cells ex vivo or to be used as vaccines to target short-lived proteins.
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8
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Adaptive Mistranslation Accelerates the Evolution of Fluconazole Resistance and Induces Major Genomic and Gene Expression Alterations in Candida albicans. mSphere 2017; 2:mSphere00167-17. [PMID: 28808688 PMCID: PMC5549176 DOI: 10.1128/msphere.00167-17] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Accepted: 07/01/2017] [Indexed: 01/24/2023] Open
Abstract
Regulated erroneous protein translation (adaptive mistranslation) increases proteome diversity and produces advantageous phenotypic variability in the human pathogen Candida albicans. It also increases fitness in the presence of fluconazole, but the underlying molecular mechanism is not understood. To address this question, we evolved hypermistranslating and wild-type strains in the absence and presence of fluconazole and compared their fluconazole tolerance and resistance trajectories during evolution. The data show that mistranslation increases tolerance and accelerates the acquisition of resistance to fluconazole. Genome sequencing, array-based comparative genome analysis, and gene expression profiling revealed that during the course of evolution in fluconazole, the range of mutational and gene deregulation differences was distinctively different and broader in the hypermistranslating strain, including multiple chromosome duplications, partial chromosome deletions, and polyploidy. Especially, the increased accumulation of loss-of-heterozygosity events, aneuploidy, translational and cell surface modifications, and differences in drug efflux seem to mediate more rapid drug resistance acquisition under mistranslation. Our observations support a pivotal role for adaptive mistranslation in the evolution of drug resistance in C. albicans. IMPORTANCE Infectious diseases caused by drug-resistant fungi are an increasing threat to public health because of the high mortality rates and high costs associated with treatment. Thus, understanding of the molecular mechanisms of drug resistance is of crucial interest for the medical community. Here we investigated the role of regulated protein mistranslation, a characteristic mechanism used by C. albicans to diversify its proteome, in the evolution of fluconazole resistance. Such codon ambiguity is usually considered highly deleterious, yet recent studies found that mistranslation can boost adaptation in stressful environments. Our data reveal that CUG ambiguity diversifies the genome in multiple ways and that the full spectrum of drug resistance mechanisms in C. albicans goes beyond the traditional pathways that either regulate drug efflux or alter the interactions of drugs with their targets. The present work opens new avenues to understand the molecular and genetic basis of microbial drug resistance.
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9
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Schwartz MH, Pan T. Function and origin of mistranslation in distinct cellular contexts. Crit Rev Biochem Mol Biol 2017; 52:205-219. [PMID: 28075177 DOI: 10.1080/10409238.2016.1274284] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Mistranslation describes errors during protein synthesis that prevent the amino acid sequences specified in the genetic code from being reflected within proteins. For a long time, mistranslation has largely been considered an aberrant cellular process that cells actively avoid at all times. However, recent evidence has demonstrated that cells from all three domains of life not only tolerate certain levels and forms of mistranslation, but actively induce mistranslation under certain circumstances. To this end, dedicated biological mechanisms have recently been found to reduce translational fidelity, which indicates that mistranslation is not exclusively an erroneous process and can even benefit cells in particular cellular contexts. There currently exists a spectrum of mistranslational processes that differ not only in their origins, but also in their molecular and cellular effects. These findings suggest that the optimal degree of translational fidelity largely depends on a specific cellular context. This review aims to conceptualize the basis and functional consequence of the diverse types of mistranslation that have been described so far.
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Affiliation(s)
- Michael H Schwartz
- a Department of Biochemistry and Molecular Biology , University of Chicago, Chicago , IL , USA
| | - Tao Pan
- a Department of Biochemistry and Molecular Biology , University of Chicago, Chicago , IL , USA
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10
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Schwartz MH, Waldbauer JR, Zhang L, Pan T. Global tRNA misacylation induced by anaerobiosis and antibiotic exposure broadly increases stress resistance in Escherichia coli. Nucleic Acids Res 2016; 44:10292-10303. [PMID: 27672035 PMCID: PMC5137444 DOI: 10.1093/nar/gkw856] [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: 07/20/2016] [Revised: 09/14/2016] [Accepted: 09/16/2016] [Indexed: 12/22/2022] Open
Abstract
High translational fidelity is commonly considered a requirement for optimal cellular health and protein function. However, recent findings have shown that inducible mistranslation specifically with methionine engendered at the tRNA charging level occurs in mammalian cells, yeast and archaea, yet it was unknown whether bacteria were capable of mounting a similar response. Here, we demonstrate that Escherichia coli misacylates non-methionyl-tRNAs with methionine in response to anaerobiosis and antibiotic exposure via the methionyl–tRNA synthetase (MetRS). Two MetRS succinyl-lysine modifications independently confer high tRNA charging fidelity to the otherwise promiscuous, unmodified enzyme. Strains incapable of tRNA mismethionylation are less adept at growth in the presence of antibiotics and stressors. The presence of tRNA mismethionylation and its potential role in mistranslation within the bacterial domain establishes this response as a pervasive biological mechanism and connects it to diverse cellular functions and modes of fitness.
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Affiliation(s)
- Michael H Schwartz
- Department of Biochemistry and Molecular Biology, University of Chicago, 929 E. 57th St., Chicago, IL 60637, USA.,Committee on Microbiology, University of Chicago, 929 E. 57th St., Chicago, IL 60637, USA
| | - Jacob R Waldbauer
- Department of Geophysical Sciences, University of Chicago, 5734 S. Ellis Ave., Chicago, IL 60637, USA
| | - Lichun Zhang
- Department of Geophysical Sciences, University of Chicago, 5734 S. Ellis Ave., Chicago, IL 60637, USA
| | - Tao Pan
- Department of Biochemistry and Molecular Biology, University of Chicago, 929 E. 57th St., Chicago, IL 60637, USA .,Committee on Microbiology, University of Chicago, 929 E. 57th St., Chicago, IL 60637, USA
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11
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Abstract
Our genome is protected from the introduction of mutations by high fidelity replication and an extensive network of DNA damage response and repair mechanisms. However, the expression of our genome, via RNA and protein synthesis, allows for more diversity in translating genetic information. In addition, the splicing process has become less stringent over evolutionary time allowing for a substantial increase in the diversity of transcripts generated. The result is a diverse transcriptome and proteome that harbor selective advantages over a more tightly regulated system. Here, we describe mechanisms in place that both safeguard the genome and promote translational diversity, with emphasis on post-transcriptional RNA processing.
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Affiliation(s)
- Brian Magnuson
- Department of Radiation Oncology, University of Michigan Comprehensive Cancer Center, and Translational Oncology Program, University of Michigan, Ann Arbor, USA; Department of Environmental Health Sciences, School of Public Health, University of Michigan, Ann Arbor, USA
| | - Karan Bedi
- Department of Radiation Oncology, University of Michigan Comprehensive Cancer Center, and Translational Oncology Program, University of Michigan, Ann Arbor, USA
| | - Mats Ljungman
- Department of Radiation Oncology, University of Michigan Comprehensive Cancer Center, and Translational Oncology Program, University of Michigan, Ann Arbor, USA; Department of Environmental Health Sciences, School of Public Health, University of Michigan, Ann Arbor, USA.
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12
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Wang X, Pan T. Stress Response and Adaptation Mediated by Amino Acid Misincorporation during Protein Synthesis. Adv Nutr 2016; 7:773S-9S. [PMID: 27422514 PMCID: PMC4942860 DOI: 10.3945/an.115.010991] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Translation of genetic information into functional proteins is critical for all cellular life. Accurate protein synthesis relies on proper aminoacylation of transfer RNAs (tRNAs) and decoding of mRNAs by the ribosome with the use of aminoacyl-tRNAs. Mistranslation can lead to pathologic consequences. All cells contain elaborate quality control mechanisms in translation, although translational fidelity may be regulated by various factors such as nutrient limitation or reactive oxygen species. Translation fidelity is maintained via the accuracy of tRNA aminoacylation by the aminoacyl-tRNA synthetases and matching of the mRNA codon with the tRNA anticodon by the ribosome. Stringent substrate discrimination and proofreading are critical in aminoacylating tRNAs with their cognate amino acid to maintain high accuracy of translation. Although the composition of the cellular proteome generally adheres to the genetic code, accumulating evidence indicates that cells can also deliberately mistranslate; they synthesize mutant proteins that deviate from the genetic code in response to stress or environmental changes. Mistranslation with tRNA charged with noncognate amino acids can expand the proteome to enhance stress response and help adaptation. Here, we review current knowledge on mistranslation through tRNA misacylation and describe advances in our understanding of translational control in the regulation of stress response and human diseases.
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Affiliation(s)
- Xiaoyun Wang
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL
| | - Tao Pan
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL
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13
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Wang X, Pan T. Methionine Mistranslation Bypasses the Restraint of the Genetic Code to Generate Mutant Proteins with Distinct Activities. PLoS Genet 2015; 11:e1005745. [PMID: 26709516 PMCID: PMC4692448 DOI: 10.1371/journal.pgen.1005745] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Accepted: 11/25/2015] [Indexed: 01/01/2023] Open
Abstract
Although mistranslation is commonly believed to be deleterious, recent evidence indicates that mistranslation can be actively regulated and be beneficial in stress response. Methionine mistranslation in mammalian cells is regulated by reactive oxygen species where cells deliberately alter the proteome through incorporating Met at non-Met positions to enhance oxidative stress response. However, it was not known whether specific, mistranslated mutant proteins have distinct activities from the wild-type protein whose sequence is restrained by the genetic code. Here, we show that Met mistranslation with and without Ca2+ overload generates specific mutant Ca2+/calmodulin-dependent protein kinase II (CaMKII) proteins substituting non-Met with Met at multiple locations. Compared to the genetically encoded wild-type CaMKII, specific mutant CaMKIIs can have distinct activation profiles, intracellular localization and enhanced phenotypes. Our results demonstrate that Met-mistranslation, or “Met-scan” can indeed generate mutant proteins in cells that expand the activity profile of the wild-type protein, and provide a molecular mechanism for the role of regulated mistranslation. Methionine-mistranslation is a recently discovered phenomenon where mammalian cells deliberately mischarge non-Met-tRNAs with amino acid methionine in unstressed cells and in response to innate immune and chemically triggered oxidative stress. These mischarged tRNAs are used in translation to generate mutant proteins containing non-Met to Met substitutions. Accumulating evidence shows that cells employ regulated mistranslation to enhance response to oxidative and other stresses. However, it was unknown whether any specific mutant proteins generated in mistranslation truly have distinct activities as the wild-type protein. Here, we identify and characterize naturally occurring Met-mistranslated proteins in human cells and show that specific Met-mistranslated proteins can have very distinct properties compared to the wild-type protein in vitro and in vivo. For the Ca2+/calmodulin-dependent protein kinase II (CaMKII), Met-mistranslated CaMKII show significant differences in catalytic activities, subcellular localization and elevated caspase-3 activity from the wild-type CaMKII. Our results provide a molecular mechanism on how mistranslation is used as an adaptive mechanism to stress, and establish Met-mistranslation as a nature’s way to overcome the restraint on the protein sequence by the genetic code.
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Affiliation(s)
- Xiaoyun Wang
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois, United States of America
- * E-mail: (XW); (TP)
| | - Tao Pan
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois, United States of America
- * E-mail: (XW); (TP)
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Hamashima K, Tomita M, Kanai A. Expansion of Noncanonical V-Arm-Containing tRNAs in Eukaryotes. Mol Biol Evol 2015; 33:530-40. [DOI: 10.1093/molbev/msv253] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
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15
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Ragionieri L, Vitorino R, Frommlet J, Oliveira JL, Gaspar P, Ribas de Pouplana L, Santos MAS, Moura GR. Improving the accuracy of recombinant protein production through integration of bioinformatics, statistical and mass spectrometry methodologies. FEBS J 2015; 282:769-87. [DOI: 10.1111/febs.13181] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Revised: 10/09/2014] [Accepted: 12/16/2014] [Indexed: 02/05/2023]
Affiliation(s)
- Lapo Ragionieri
- RNA and Genome Biology Laboratories; Department of Biology/Health Sciences; Centro de Estudos do Ambiente e do Mar iBiMED; University of Aveiro; Portugal
| | - Rui Vitorino
- Department of Chemistry; University of Aveiro; Portugal
| | - Joerg Frommlet
- Department of Biology and Centro de Estudos do Ambiente e do Mar; University of Aveiro; Portugal
| | - José L. Oliveira
- Department of Electronics; Telecommunications and Informatics and Instituto de Engenharia Electrónica e Telemática de Aveiro; University of Aveiro; Portugal
| | - Paulo Gaspar
- Department of Electronics; Telecommunications and Informatics and Instituto de Engenharia Electrónica e Telemática de Aveiro; University of Aveiro; Portugal
| | - Lluís Ribas de Pouplana
- Institute for Research in Biomedicine; Barcelona Spain
- Catalan Institution for Research and Advanced Studies; Barcelona Spain
| | - Manuel A. Silva Santos
- RNA and Genome Biology Laboratories; Department of Biology/Health Sciences; Centro de Estudos do Ambiente e do Mar iBiMED; University of Aveiro; Portugal
| | - Gabriela Ribeiro Moura
- RNA and Genome Biology Laboratories; Department of Biology/Health Sciences; Centro de Estudos do Ambiente e do Mar iBiMED; University of Aveiro; Portugal
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16
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Hamashima K, Mori M, Andachi Y, Tomita M, Kohara Y, Kanai A. Analysis of genetic code ambiguity arising from nematode-specific misacylated tRNAs. PLoS One 2015; 10:e0116981. [PMID: 25602944 PMCID: PMC4300185 DOI: 10.1371/journal.pone.0116981] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Accepted: 12/17/2014] [Indexed: 12/22/2022] Open
Abstract
The faithful translation of the genetic code requires the highly accurate aminoacylation of transfer RNAs (tRNAs). However, it has been shown that nematode-specific V-arm-containing tRNAs (nev-tRNAs) are misacylated with leucine in vitro in a manner that transgresses the genetic code. nev-tRNA(Gly) (CCC) and nev-tRNA(Ile) (UAU), which are the major nev-tRNA isotypes, could theoretically decode the glycine (GGG) codon and isoleucine (AUA) codon as leucine, causing GGG and AUA codon ambiguity in nematode cells. To test this hypothesis, we investigated the functionality of nev-tRNAs and their impact on the proteome of Caenorhabditis elegans. Analysis of the nucleotide sequences in the 3' end regions of the nev-tRNAs showed that they had matured correctly, with the addition of CCA, which is a crucial posttranscriptional modification required for tRNA aminoacylation. The nuclear export of nev-tRNAs was confirmed with an analysis of their subcellular localization. These results show that nev-tRNAs are processed to their mature forms like common tRNAs and are available for translation. However, a whole-cell proteome analysis found no detectable level of nev-tRNA-induced mistranslation in C. elegans cells, suggesting that the genetic code is not ambiguous, at least under normal growth conditions. Our findings indicate that the translational fidelity of the nematode genetic code is strictly maintained, contrary to our expectations, although deviant tRNAs with misacylation properties are highly conserved in the nematode genome.
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Affiliation(s)
- Kiyofumi Hamashima
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Japan
- Systems Biology Program, Graduate School of Media and Governance, Keio University, Fujisawa, Japan
| | - Masaru Mori
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Japan
- Systems Biology Program, Graduate School of Media and Governance, Keio University, Fujisawa, Japan
| | - Yoshiki Andachi
- Genome Biology Laboratory, National Institute of Genetics, Mishima, Japan
- Department of Genetics, SOKENDAI, Mishima, Japan
| | - Masaru Tomita
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Japan
- Systems Biology Program, Graduate School of Media and Governance, Keio University, Fujisawa, Japan
- Faculty of Environment and Information Studies, Keio University, Fujisawa, Japan
| | - Yuji Kohara
- Genome Biology Laboratory, National Institute of Genetics, Mishima, Japan
- Department of Genetics, SOKENDAI, Mishima, Japan
| | - Akio Kanai
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Japan
- Systems Biology Program, Graduate School of Media and Governance, Keio University, Fujisawa, Japan
- Faculty of Environment and Information Studies, Keio University, Fujisawa, Japan
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17
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Mycobacterial mistranslation is necessary and sufficient for rifampicin phenotypic resistance. Proc Natl Acad Sci U S A 2014; 111:1132-7. [PMID: 24395793 DOI: 10.1073/pnas.1317580111] [Citation(s) in RCA: 136] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Errors are inherent in all biological systems. Errors in protein translation are particularly frequent giving rise to a collection of protein quasi-species, the diversity of which will vary according to the error rate. As mistranslation rates rise, these new proteins could produce new phenotypes, although none have been identified to date. Here, we find that mycobacteria substitute glutamate for glutamine and aspartate for asparagine at high rates under specific growth conditions. Increasing the substitution rate results in remarkable phenotypic resistance to rifampicin, whereas decreasing mistranslation produces increased susceptibility to the antibiotic. These phenotypic changes are reflected in differential susceptibility of RNA polymerase to the drug. We propose that altering translational fidelity represents a unique form of environmental adaptation.
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18
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Porceddu A, Zenoni S, Camiolo S. The signatures of selection for translational accuracy in plant genes. Genome Biol Evol 2013; 5:1117-26. [PMID: 23695187 PMCID: PMC3698923 DOI: 10.1093/gbe/evt078] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Little is known about the natural selection of synonymous codons within the coding sequences of plant genes. We analyzed the distribution of synonymous codons within plant coding sequences and found that preferred codons tend to encode the more conserved and functionally important residues of plant proteins. This was consistent among several synonymous codon families and applied to genes with different expression profiles and functions. Most of the randomly chosen alternative sets of codons scored weaker associations than the actual sets of preferred codons, suggesting that codon position within plant genes and codon usage bias have coevolved to maximize translational accuracy. All these findings are consistent with the mistranslation-induced protein misfolding theory, which predicts the natural selection of highly preferred codons more frequently at sites where translation errors could compromise protein folding or functionality. Our results will provide an important insight in future studies of protein folding, molecular evolution, and transgene design for optimal expression.
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Affiliation(s)
- Andrea Porceddu
- Dipartimento di Agraria, Sezione di Agronomia e Coltivazione Erbacee Genetica-SACEG, Università degli studi di Sassari, Italy.
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19
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Abstract
The composition of the cellular proteome is commonly thought to strictly adhere to the genetic code. However, accumulating evidence indicates that cells also regulate the synthesis of mutant protein molecules that deviate from the genetic code. Production of mutant proteins generally occurs when cells are stressed or when they undergo environmental adaptation, but production varies in amounts and specificity. The deliberate synthesis of mutant proteins suggests that some of these proteins can be useful in cellular stress response and adaptation. This review describes the occurrence of, the translation mechanisms for, and the functional hypotheses on regulated synthesis of mutant proteins.
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Affiliation(s)
- Tao Pan
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois 60637;
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Ryall B, Eydallin G, Ferenci T. Culture history and population heterogeneity as determinants of bacterial adaptation: the adaptomics of a single environmental transition. Microbiol Mol Biol Rev 2012; 76:597-625. [PMID: 22933562 PMCID: PMC3429624 DOI: 10.1128/mmbr.05028-11] [Citation(s) in RCA: 102] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Diversity in adaptive responses is common within species and populations, especially when the heterogeneity of the frequently large populations found in environments is considered. By focusing on events in a single clonal population undergoing a single transition, we discuss how environmental cues and changes in growth rate initiate a multiplicity of adaptive pathways. Adaptation is a comprehensive process, and stochastic, regulatory, epigenetic, and mutational changes can contribute to fitness and overlap in timing and frequency. We identify culture history as a major determinant of both regulatory adaptations and microevolutionary change. Population history before a transition determines heterogeneities due to errors in translation, stochastic differences in regulation, the presence of aged, damaged, cheating, or dormant cells, and variations in intracellular metabolite or regulator concentrations. It matters whether bacteria come from dense, slow-growing, stressed, or structured states. Genotypic adaptations are history dependent due to variations in mutation supply, contingency gene changes, phase variation, lateral gene transfer, and genome amplifications. Phenotypic adaptations underpin genotypic changes in situations such as stress-induced mutagenesis or prophage induction or in biofilms to give a continuum of adaptive possibilities. Evolutionary selection additionally provides diverse adaptive outcomes in a single transition and generally does not result in single fitter types. The totality of heterogeneities in an adapting population increases the chance that at least some individuals meet immediate or future challenges. However, heterogeneity complicates the adaptomics of single transitions, and we propose that subpopulations will need to be integrated into future population biology and systems biology predictions of bacterial behavior.
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Affiliation(s)
- Ben Ryall
- School of Molecular Bioscience, University of Sydney, New South Wales, Australia
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21
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Novoa EM, Ribas de Pouplana L. Speeding with control: codon usage, tRNAs, and ribosomes. Trends Genet 2012; 28:574-81. [PMID: 22921354 DOI: 10.1016/j.tig.2012.07.006] [Citation(s) in RCA: 218] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2012] [Revised: 07/19/2012] [Accepted: 07/20/2012] [Indexed: 11/26/2022]
Abstract
Codon usage and tRNA abundance are critical parameters for gene synthesis. However, the forces determining codon usage bias within genomes and between organisms, as well as the functional roles of biased codon compositions, remain poorly understood. Similarly, the composition and dynamics of mature tRNA populations in cells in terms of isoacceptor abundances, and the prevalence and function of base modifications are not well understood. As we begin to decipher some of the rules that govern codon usage and tRNA abundances, it is becoming clear that these parameters are a way to not only increase gene expression, but also regulate the speed of ribosomal translation, the efficiency of protein folding, and the coordinated expression of functionally related gene families. Here, we discuss the importance of codon-anticodon interactions in translation regulation and highlight the contribution of non-random codon distributions and post-transcriptional base modifications to this regulation.
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Affiliation(s)
- Eva Maria Novoa
- Institute for Research in Biomedicine (IRB), c/Baldiri Reixac 15-21 08028, Barcelona, Catalonia, Spain
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22
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Huang Y, O'Mara B, Conover M, Ludwig R, Fu J, Tao L, Li ZJ, Rieble S, Grace MJ, Russell RJ. Glycine to glutamic acid misincorporation observed in a recombinant protein expressed by Escherichia coli cells. Protein Sci 2012; 21:625-32. [PMID: 22362707 DOI: 10.1002/pro.2046] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Accepted: 02/10/2012] [Indexed: 01/14/2023]
Abstract
A novel amino acid misincorporation, in which the intended glycine (Gly) residues were replaced by a glutamic acid (Glu), was observed in a recombinant protein expressed by Escherichia coli. The misincorporation was identified by peptide mapping and liquid chromatography-tandem mass spectrometric analysis on proteolyzed peptides of the protein and verified using the corresponding synthetic peptides containing the misincorporated residues. Analysis of the distribution of the misincorporated residues and their codon usage shows strong correlation between this misincorporation and the use of rarely used codon within the E. coli expression system. Results in this study suggest that the usage of the rare codon GGA has resulted in a Glu for Gly misincorporation.
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Affiliation(s)
- Yunping Huang
- Department of Biologics Product & Process Development, Bristol-Myers Squibb Technical Operations, Princeton, New Jersey 08543, USA.
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A ribosomal misincorporation of Lys for Arg in human triosephosphate isomerase expressed in Escherichia coli gives rise to two protein populations. PLoS One 2011; 6:e21035. [PMID: 21738601 PMCID: PMC3125179 DOI: 10.1371/journal.pone.0021035] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2011] [Accepted: 05/17/2011] [Indexed: 11/20/2022] Open
Abstract
We previously observed that human homodimeric triosephosphate isomerase (HsTIM) expressed in Escherichia coli and purified to apparent homogeneity exhibits two significantly different thermal transitions. A detailed exploration of the phenomenon showed that the preparations contain two proteins; one has the expected theoretical mass, while the mass of the other is 28 Da lower. The two proteins were separated by size exclusion chromatography in 3 M urea. Both proteins correspond to HsTIM as shown by Tandem Mass Spectrometry (LC/ESI-MS/MS). The two proteins were present in nearly equimolar amounts under certain growth conditions. They were catalytically active, but differed in molecular mass, thermostability, susceptibility to urea and proteinase K. An analysis of the nucleotides in the human TIM gene revealed the presence of six codons that are not commonly used in E. coli. We examined if they were related to the formation of the two proteins. We found that expression of the enzyme in a strain that contains extra copies of genes that encode for tRNAs that frequently limit translation of heterologous proteins (Arg, Ile, Leu), as well as silent mutations of two consecutive rare Arg codons (positions 98 and 99), led to the exclusive production of the more stable protein. Further analysis by LC/ESI-MS/MS showed that the 28 Da mass difference is due to the substitution of a Lys for an Arg residue at position 99. Overall, our work shows that two proteins with different biochemical and biophysical properties that coexist in the same cell environment are translated from the same nucleotide sequence frame.
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Kawai M, Furuta Y, Yahara K, Tsuru T, Oshima K, Handa N, Takahashi N, Yoshida M, Azuma T, Hattori M, Uchiyama I, Kobayashi I. Evolution in an oncogenic bacterial species with extreme genome plasticity: Helicobacter pylori East Asian genomes. BMC Microbiol 2011; 11:104. [PMID: 21575176 PMCID: PMC3120642 DOI: 10.1186/1471-2180-11-104] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2010] [Accepted: 05/16/2011] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND The genome of Helicobacter pylori, an oncogenic bacterium in the human stomach, rapidly evolves and shows wide geographical divergence. The high incidence of stomach cancer in East Asia might be related to bacterial genotype. We used newly developed comparative methods to follow the evolution of East Asian H. pylori genomes using 20 complete genome sequences from Japanese, Korean, Amerind, European, and West African strains. RESULTS A phylogenetic tree of concatenated well-defined core genes supported divergence of the East Asian lineage (hspEAsia; Japanese and Korean) from the European lineage ancestor, and then from the Amerind lineage ancestor. Phylogenetic profiling revealed a large difference in the repertoire of outer membrane proteins (including oipA, hopMN, babABC, sabAB and vacA-2) through gene loss, gain, and mutation. All known functions associated with molybdenum, a rare element essential to nearly all organisms that catalyzes two-electron-transfer oxidation-reduction reactions, appeared to be inactivated. Two pathways linking acetyl~CoA and acetate appeared intact in some Japanese strains. Phylogenetic analysis revealed greater divergence between the East Asian (hspEAsia) and the European (hpEurope) genomes in proteins in host interaction, specifically virulence factors (tipα), outer membrane proteins, and lipopolysaccharide synthesis (human Lewis antigen mimicry) enzymes. Divergence was also seen in proteins in electron transfer and translation fidelity (miaA, tilS), a DNA recombinase/exonuclease that recognizes genome identity (addA), and DNA/RNA hybrid nucleases (rnhAB). Positively selected amino acid changes between hspEAsia and hpEurope were mapped to products of cagA, vacA, homC (outer membrane protein), sotB (sugar transport), and a translation fidelity factor (miaA). Large divergence was seen in genes related to antibiotics: frxA (metronidazole resistance), def (peptide deformylase, drug target), and ftsA (actin-like, drug target). CONCLUSIONS These results demonstrate dramatic genome evolution within a species, especially in likely host interaction genes. The East Asian strains appear to differ greatly from the European strains in electron transfer and redox reactions. These findings also suggest a model of adaptive evolution through proteome diversification and selection through modulation of translational fidelity. The results define H. pylori East Asian lineages and provide essential information for understanding their pathogenesis and designing drugs and therapies that target them.
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Affiliation(s)
- Mikihiko Kawai
- Department of Medical Genome Sciences, Graduate School of Frontier Sciences, University of Tokyo, Minato-ku, Tokyo, 108-8639, Japan
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