1
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Aviner R, Lee TT, Masto VB, Li KH, Andino R, Frydman J. Polyglutamine-mediated ribotoxicity disrupts proteostasis and stress responses in Huntington's disease. Nat Cell Biol 2024; 26:892-902. [PMID: 38741019 DOI: 10.1038/s41556-024-01414-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Accepted: 04/01/2024] [Indexed: 05/16/2024]
Abstract
Huntington's disease (HD) is a neurodegenerative disorder caused by expansion of a CAG trinucleotide repeat in the Huntingtin (HTT) gene, encoding a homopolymeric polyglutamine (polyQ) tract. Although mutant HTT (mHTT) protein is known to aggregate, the links between aggregation and neurotoxicity remain unclear. Here we show that both translation and aggregation of wild-type HTT and mHTT are regulated by a stress-responsive upstream open reading frame and that polyQ expansions cause abortive translation termination and release of truncated, aggregation-prone mHTT fragments. Notably, we find that mHTT depletes translation elongation factor eIF5A in brains of symptomatic HD mice and cultured HD cells, leading to pervasive ribosome pausing and collisions. Loss of eIF5A disrupts homeostatic controls and impairs recovery from acute stress. Importantly, drugs that inhibit translation initiation reduce premature termination and mitigate this escalating cascade of ribotoxic stress and dysfunction in HD.
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Affiliation(s)
- Ranen Aviner
- Department of Biology and Department of Genetics, Stanford University, Stanford, CA, USA
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA, USA
- Chan Zuckerberg Biohub San Francisco, San Francisco, CA, USA
| | - Ting-Ting Lee
- Department of Biology and Department of Genetics, Stanford University, Stanford, CA, USA
| | - Vincent B Masto
- Department of Biology and Department of Genetics, Stanford University, Stanford, CA, USA
| | - Kathy H Li
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA, USA
| | - Raul Andino
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA, USA
| | - Judith Frydman
- Department of Biology and Department of Genetics, Stanford University, Stanford, CA, USA.
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2
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Flügel T, Schacherl M, Unbehaun A, Schroeer B, Dabrowski M, Bürger J, Mielke T, Sprink T, Diebolder CA, Guillén Schlippe YV, Spahn CMT. Transient disome complex formation in native polysomes during ongoing protein synthesis captured by cryo-EM. Nat Commun 2024; 15:1756. [PMID: 38409277 PMCID: PMC10897467 DOI: 10.1038/s41467-024-46092-3] [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: 04/26/2023] [Accepted: 02/13/2024] [Indexed: 02/28/2024] Open
Abstract
Structural studies of translating ribosomes traditionally rely on in vitro assembly and stalling of ribosomes in defined states. To comprehensively visualize bacterial translation, we reactivated ex vivo-derived E. coli polysomes in the PURE in vitro translation system and analyzed the actively elongating polysomes by cryo-EM. We find that 31% of 70S ribosomes assemble into disome complexes that represent eight distinct functional states including decoding and termination intermediates, and a pre-nucleophilic attack state. The functional diversity of disome complexes together with RNase digest experiments suggests that paused disome complexes transiently form during ongoing elongation. Structural analysis revealed five disome interfaces between leading and queueing ribosomes that undergo rearrangements as the leading ribosome traverses through the elongation cycle. Our findings reveal at the molecular level how bL9's CTD obstructs the factor binding site of queueing ribosomes to thwart harmful collisions and illustrate how translation dynamics reshape inter-ribosomal contacts.
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Affiliation(s)
- Timo Flügel
- Charité - Univesitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Medical Physics and Biophysics, Berlin, Germany
| | - Magdalena Schacherl
- Charité - Univesitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Medical Physics and Biophysics, Berlin, Germany
| | - Anett Unbehaun
- Charité - Univesitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Medical Physics and Biophysics, Berlin, Germany
| | - Birgit Schroeer
- Charité - Univesitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Medical Physics and Biophysics, Berlin, Germany
| | - Marylena Dabrowski
- Charité - Univesitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Medical Physics and Biophysics, Berlin, Germany
| | - Jörg Bürger
- Charité - Univesitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Medical Physics and Biophysics, Berlin, Germany
- Max Planck Institute for Molecular Genetics, Microscopy and Cryo-Electron Microscopy Service Group, Berlin, Germany
| | - Thorsten Mielke
- Max Planck Institute for Molecular Genetics, Microscopy and Cryo-Electron Microscopy Service Group, Berlin, Germany
| | - Thiemo Sprink
- Core Facility for Cryo-Electron Microscopy, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Technology Platform Cryo-EM, Berlin, Germany
| | - Christoph A Diebolder
- Core Facility for Cryo-Electron Microscopy, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Technology Platform Cryo-EM, Berlin, Germany
| | - Yollete V Guillén Schlippe
- Charité - Univesitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Medical Physics and Biophysics, Berlin, Germany.
| | - Christian M T Spahn
- Charité - Univesitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Medical Physics and Biophysics, Berlin, Germany.
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3
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Mao Y, Qian SB. Making sense of mRNA translational "noise". Semin Cell Dev Biol 2024; 154:114-122. [PMID: 36925447 PMCID: PMC10500040 DOI: 10.1016/j.semcdb.2023.03.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 03/09/2023] [Accepted: 03/09/2023] [Indexed: 03/15/2023]
Abstract
The importance of translation fidelity has been apparent since the discovery of genetic code. It is commonly believed that translation deviating from the main coding region is to be avoided at all times inside cells. However, ribosome profiling and mass spectrometry have revealed pervasive noncanonical translation. Both the scope and origin of translational "noise" are just beginning to be appreciated. Although largely overlooked, those translational "noises" are associated with a wide range of cellular functions, such as producing unannotated protein products. Furthermore, the dynamic nature of translational "noise" is responsive to stress conditions, highlighting the beneficial effect of translational "noise" in stress adaptation. Mechanistic investigation of translational "noise" will provide better insight into the mechanisms of translational regulation. Ultimately, they are not "noise" at all but represent a signature of cellular activities under pathophysiological conditions. Deciphering translational "noise" holds the therapeutic and diagnostic potential in a wide spectrum of human diseases.
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Affiliation(s)
- Yuanhui Mao
- Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853, USA
| | - Shu-Bing Qian
- Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853, USA.
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4
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Springstein BL, Paulo JA, Park H, Henry K, Fleming E, Feder Z, Harper JW, Hochschild A. Systematic analysis of nonprogrammed frameshift suppression in E. coli via translational tiling proteomics. Proc Natl Acad Sci U S A 2024; 121:e2317453121. [PMID: 38289956 PMCID: PMC10861913 DOI: 10.1073/pnas.2317453121] [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: 10/13/2023] [Accepted: 12/20/2023] [Indexed: 02/01/2024] Open
Abstract
The synthesis of proteins as encoded in the genome depends critically on translational fidelity. Nevertheless, errors inevitably occur, and those that result in reading frame shifts are particularly consequential because the resulting polypeptides are typically nonfunctional. Despite the generally maladaptive impact of such errors, the proper decoding of certain mRNAs, including many viral mRNAs, depends on a process known as programmed ribosomal frameshifting. The fact that these programmed events, commonly involving a shift to the -1 frame, occur at specific evolutionarily optimized "slippery" sites has facilitated mechanistic investigation. By contrast, less is known about the scope and nature of error (i.e., nonprogrammed) frameshifting. Here, we examine error frameshifting by monitoring spontaneous frameshift events that suppress the effects of single base pair deletions affecting two unrelated test proteins. To map the precise sites of frameshifting, we developed a targeted mass spectrometry-based method called "translational tiling proteomics" for interrogating the full set of possible -1 slippage events that could produce the observed frameshift suppression. Surprisingly, such events occur at many sites along the transcripts, involving up to one half of the available codons. Only a subset of these resembled canonical "slippery" sites, implicating alternative mechanisms potentially involving noncognate mispairing events. Additionally, the aggregate frequency of these events (ranging from 1 to 10% in our test cases) was higher than we might have anticipated. Our findings point to an unexpected degree of mechanistic diversity among ribosomal frameshifting events and suggest that frameshifted products may contribute more significantly to the proteome than generally assumed.
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Affiliation(s)
| | - Joao A. Paulo
- Department of Cell Biology, Harvard Medical School, BostonMA02115
| | - Hankum Park
- Department of Cell Biology, Harvard Medical School, BostonMA02115
| | - Kemardo Henry
- Department of Microbiology, Harvard Medical School, BostonMA02115
| | - Eleanor Fleming
- Department of Microbiology, Harvard Medical School, BostonMA02115
| | - Zoë Feder
- Department of Microbiology, Harvard Medical School, BostonMA02115
| | - J. Wade Harper
- Department of Cell Biology, Harvard Medical School, BostonMA02115
| | - Ann Hochschild
- Department of Microbiology, Harvard Medical School, BostonMA02115
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5
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Hong HR, Prince CR, Tetreault DD, Wu L, Feaga HA. YfmR is a translation factor that prevents ribosome stalling and cell death in the absence of EF-P. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.04.552005. [PMID: 37577462 PMCID: PMC10418254 DOI: 10.1101/2023.08.04.552005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/15/2023]
Abstract
Protein synthesis is performed by the ribosome and a host of highly conserved elongation factors. Elongation factor P (EF-P) prevents ribosome stalling at difficult-to-translate sequences, particularly polyproline tracts. In bacteria, phenotypes associated with efp deletion range from modest to lethal, suggesting that some species encode an additional translation factor that has similar function to EF-P. Here we identify YfmR as a translation factor that is essential in the absence of EF-P in B. subtilis. YfmR is an ABCF ATPase that is closely related to both Uup and EttA, ABCFs that bind the ribosomal E-site and are conserved in more than 50% of bacterial genomes. We show that YfmR associates with actively translating ribosomes and that depleting YfmR from Δefp cells causes severe ribosome stalling at a polyproline tract in vivo. YfmR depletion from Δefp cells was lethal, and caused reduced levels of actively translating ribosomes. Our results therefore identify YfmR as an important translation factor that is essential in B. subtilis in the absence of EF-P.
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Affiliation(s)
- Hye-Rim Hong
- Department of Microbiology, Cornell University, Ithaca, NY 14853
| | | | | | - Letian Wu
- Department of Microbiology, Cornell University, Ithaca, NY 14853
| | - Heather A. Feaga
- Department of Microbiology, Cornell University, Ithaca, NY 14853
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6
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Conor Moran J, Brivanlou A, Brischigliaro M, Fontanesi F, Rouskin S, Barrientos A. The human mitochondrial mRNA structurome reveals mechanisms of gene expression. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.31.564750. [PMID: 37961485 PMCID: PMC10635011 DOI: 10.1101/2023.10.31.564750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
The mammalian mitochondrial genome encodes thirteen oxidative phosphorylation system proteins, crucial in aerobic energy transduction. These proteins are translated from 9 monocistronic and 2 bicistronic transcripts, whose native structures remain unexplored, leaving fundamental molecular determinants of mitochondrial gene expression unknown. To address this gap, we developed a mitoDMS-MaPseq approach and used DREEM clustering to resolve the native human mitochondrial mt-mRNA structurome. We gained insights into mt-mRNA biology and translation regulatory mechanisms, including a unique programmed ribosomal frameshifting for the ATP8/ATP6 transcript. Furthermore, absence of the mt-mRNA maintenance factor LRPPRC led to a mitochondrial transcriptome structured differently, with specific mRNA regions exhibiting increased or decreased structuredness. This highlights the role of LRPPRC in maintaining mRNA folding to promote mt-mRNA stabilization and efficient translation. In conclusion, our mt-mRNA folding maps reveal novel mitochondrial gene expression mechanisms, serving as a detailed reference and tool for studying them in different physiological and pathological contexts.
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7
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Abstract
Protein synthesis by the ribosome is the final stage of biological information transfer and represents an irreversible commitment to gene expression. Accurate translation of messenger RNA is therefore essential to all life, and spontaneous errors by the translational machinery are highly infrequent (∼1/100,000 codons). Programmed -1 ribosomal frameshifting (-1PRF) is a mechanism in which the elongating ribosome is induced at high frequency to slip backward by one nucleotide at a defined position and to continue translation in the new reading frame. This is exploited as a translational regulation strategy by hundreds of RNA viruses, which rely on -1PRF during genome translation to control the stoichiometry of viral proteins. While early investigations of -1PRF focused on virological and biochemical aspects, the application of X-ray crystallography and cryo-electron microscopy (cryo-EM), and the advent of deep sequencing and single-molecule approaches have revealed unexpected structural diversity and mechanistic complexity. Molecular players from several model systems have now been characterized in detail, both in isolation and, more recently, in the context of the elongating ribosome. Here we provide a summary of recent advances and discuss to what extent a general model for -1PRF remains a useful way of thinking.
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Affiliation(s)
- Chris H Hill
- York Structural Biology Laboratory, York Biomedical Research Institute, Department of Biology, University of York, York, United Kingdom;
| | - Ian Brierley
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom;
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8
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Zhang D, Zhu L, Wang F, Li P, Wang Y, Gao Y. Molecular mechanisms of eukaryotic translation fidelity and their associations with diseases. Int J Biol Macromol 2023; 242:124680. [PMID: 37141965 DOI: 10.1016/j.ijbiomac.2023.124680] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Accepted: 04/27/2023] [Indexed: 05/06/2023]
Abstract
Converting genetic information into functional proteins is a complex, multi-step process, with each step being tightly regulated to ensure the accuracy of translation, which is critical to cellular health. In recent years, advances in modern biotechnology, especially the development of cryo-electron microscopy and single-molecule techniques, have enabled a clearer understanding of the mechanisms of protein translation fidelity. Although there are many studies on the regulation of protein translation in prokaryotes, and the basic elements of translation are highly conserved in prokaryotes and eukaryotes, there are still great differences in the specific regulatory mechanisms. This review describes how eukaryotic ribosomes and translation factors regulate protein translation and ensure translation accuracy. However, a certain frequency of translation errors does occur in translation, so we describe diseases that arise when the rate of translation errors reaches or exceeds a threshold of cellular tolerance.
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Affiliation(s)
- Dejiu Zhang
- Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, College of Medicine, Qingdao University, Qingdao, China
| | - Lei Zhu
- College of Basic Medical, Qingdao Binhai University, Qingdao, China
| | - Fei Wang
- Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, College of Medicine, Qingdao University, Qingdao, China
| | - Peifeng Li
- Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, College of Medicine, Qingdao University, Qingdao, China
| | - Yin Wang
- Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, College of Medicine, Qingdao University, Qingdao, China.
| | - Yanyan Gao
- Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, College of Medicine, Qingdao University, Qingdao, China.
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9
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Fromm SA, O'Connor KM, Purdy M, Bhatt PR, Loughran G, Atkins JF, Jomaa A, Mattei S. The translating bacterial ribosome at 1.55 Å resolution generated by cryo-EM imaging services. Nat Commun 2023; 14:1095. [PMID: 36841832 PMCID: PMC9968351 DOI: 10.1038/s41467-023-36742-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Accepted: 02/15/2023] [Indexed: 02/26/2023] Open
Abstract
Our understanding of protein synthesis has been conceptualised around the structure and function of the bacterial ribosome. This complex macromolecular machine is the target of important antimicrobial drugs, an integral line of defence against infectious diseases. Here, we describe how open access to cryo-electron microscopy facilities combined with bespoke user support enabled structural determination of the translating ribosome from Escherichia coli at 1.55 Å resolution. The obtained structures allow for direct determination of the rRNA sequence to identify ribosome polymorphism sites in the E. coli strain used in this study and enable interpretation of the ribosomal active and peripheral sites at unprecedented resolution. This includes scarcely populated chimeric hybrid states of the ribosome engaged in several tRNA translocation steps resolved at ~2 Å resolution. The current map not only improves our understanding of protein synthesis but also allows for more precise structure-based drug design of antibiotics to tackle rising bacterial resistance.
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Affiliation(s)
- Simon A Fromm
- EMBL Imaging Centre, European Molecular Biology Laboratory, Meyerhofstraße 1, 69117, Heidelberg, Germany
| | - Kate M O'Connor
- School of Biochemistry and Cell Biology, University College Cork, Cork, T12 XF62, Ireland
| | - Michael Purdy
- Department of Molecular Physiology and Biological Physics, School of Medicine, University of Virginia, Charlottesville, VA, USA
| | - Pramod R Bhatt
- School of Biochemistry and Cell Biology, University College Cork, Cork, T12 XF62, Ireland
| | - Gary Loughran
- School of Biochemistry and Cell Biology, University College Cork, Cork, T12 XF62, Ireland
| | - John F Atkins
- School of Biochemistry and Cell Biology, University College Cork, Cork, T12 XF62, Ireland. .,MRC Laboratory of Molecular Biology, Cambridge, CB2 0QH, UK.
| | - Ahmad Jomaa
- Department of Molecular Physiology and Biological Physics, School of Medicine, University of Virginia, Charlottesville, VA, USA. .,Centre for Cell and Membrane Physiology, University of Virginia, Charlottesville, VA, USA.
| | - Simone Mattei
- EMBL Imaging Centre, European Molecular Biology Laboratory, Meyerhofstraße 1, 69117, Heidelberg, Germany. .,Structural and Computational Biology Unit, European Molecular Biology Laboratory, Meyerhofstraße 1, 69117, Heidelberg, Germany.
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10
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Antonov IV, O’Loughlin S, Gorohovski AN, O’Connor PB, Baranov PV, Atkins JF. Streptomyces rare codon UUA: from features associated with 2 adpA related locations to candidate phage regulatory translational bypassing. RNA Biol 2023; 20:926-942. [PMID: 37968863 PMCID: PMC10732093 DOI: 10.1080/15476286.2023.2270812] [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: 11/17/2022] [Accepted: 10/02/2023] [Indexed: 11/17/2023] Open
Abstract
In Streptomyces species, the cell cycle involves a switch from an early and vegetative state to a later phase where secondary products including antibiotics are synthesized, aerial hyphae form and sporulation occurs. AdpA, which has two domains, activates the expression of numerous genes involved in the switch from the vegetative growth phase. The adpA mRNA of many Streptomyces species has a UUA codon in a linker region between 5' sequence encoding one domain and 3' sequence encoding its other and C-terminal domain. UUA codons are exceptionally rare in Streptomyces, and its functional cognate tRNA is not present in a fully modified and acylated form, in the early and vegetative phase of the cell cycle though it is aminoacylated later. Here, we report candidate recoding signals that may influence decoding of the linker region UUA. Additionally, a short ORF 5' of the main ORF has been identified with a GUG at, or near, its 5' end and an in-frame UUA near its 3' end. The latter is commonly 5 nucleotides 5' of the main ORF start. Ribosome profiling data show translation of that 5' region. Ten years ago, UUA-mediated translational bypassing was proposed as a sensor by a Streptomyces phage of its host's cell cycle stage and an effector of its lytic/lysogeny switch. We provide the first experimental evidence supportive of this proposal.
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Affiliation(s)
- Ivan V. Antonov
- Russian Academy of Science, Institute of Bioengineering, Research Center of Biotechnology, Moscow, Russia
- Laboratory of Bioinformatics, Faculty of Computer Science, National Research University Higher School of Economics, Moscow, Russia
- School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland
| | - Sinéad O’Loughlin
- School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland
| | - Alessandro N. Gorohovski
- Russian Academy of Science, Institute of Bioengineering, Research Center of Biotechnology, Moscow, Russia
- Structural Biology and BioComputing Program, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | | | - Pavel V. Baranov
- School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland
| | - John F. Atkins
- School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland
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11
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Champagne J, Mordente K, Nagel R, Agami R. Slippy-Sloppy translation: a tale of programmed and induced-ribosomal frameshifting. Trends Genet 2022; 38:1123-1133. [PMID: 35641342 DOI: 10.1016/j.tig.2022.05.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 05/10/2022] [Accepted: 05/11/2022] [Indexed: 01/24/2023]
Abstract
Programmed ribosomal frameshifting (PRF) is a key mechanism that viruses use to generate essential proteins for replication, and as a means of regulating gene expression. PRF generally involves recoding signals or frameshift stimulators to elevate the occurrence of frameshifting at shift-prone 'slippery' sequences. Given its essential role in viral replication, targeting PRF was envisioned as an attractive tool to block viral infection. However, in contrast to controlled-PRF mechanisms, recent studies have shown that ribosomes of many human cancer cell types are prone to frameshifting upon amino acid shortage; thus, these cells are deemed to be sloppy. The resulting products of a sloppy frameshift at the 'hungry' codons are aberrant proteins the degradation and display of which at the cell surface can trigger T cell activation. In this review, we address recent discoveries in ribosomal frameshifting and their functional consequences for the proteome in human cancer cells.
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Affiliation(s)
- Julien Champagne
- Division of Oncogenomics, Oncode Institute, The Netherlands Cancer Institute, Plesmanlaan 121, 1066CX Amsterdam, The Netherlands
| | - Kelly Mordente
- Division of Oncogenomics, Oncode Institute, The Netherlands Cancer Institute, Plesmanlaan 121, 1066CX Amsterdam, The Netherlands
| | - Remco Nagel
- Division of Oncogenomics, Oncode Institute, The Netherlands Cancer Institute, Plesmanlaan 121, 1066CX Amsterdam, The Netherlands
| | - Reuven Agami
- Division of Oncogenomics, Oncode Institute, The Netherlands Cancer Institute, Plesmanlaan 121, 1066CX Amsterdam, The Netherlands; Erasmus MC, Rotterdam University, Rotterdam, The Netherlands.
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12
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Xue L, Lenz S, Zimmermann-Kogadeeva M, Tegunov D, Cramer P, Bork P, Rappsilber J, Mahamid J. Visualizing translation dynamics at atomic detail inside a bacterial cell. Nature 2022; 610:205-211. [PMID: 36171285 PMCID: PMC9534751 DOI: 10.1038/s41586-022-05255-2] [Citation(s) in RCA: 50] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Accepted: 08/19/2022] [Indexed: 12/03/2022]
Abstract
Translation is the fundamental process of protein synthesis and is catalysed by the ribosome in all living cells1. Here we use advances in cryo-electron tomography and sub-tomogram analysis2,3 to visualize the structural dynamics of translation inside the bacterium Mycoplasma pneumoniae. To interpret the functional states in detail, we first obtain a high-resolution in-cell average map of all translating ribosomes and build an atomic model for the M. pneumoniae ribosome that reveals distinct extensions of ribosomal proteins. Classification then resolves 13 ribosome states that differ in their conformation and composition. These recapitulate major states that were previously resolved in vitro, and reflect intermediates during active translation. On the basis of these states, we animate translation elongation inside native cells and show how antibiotics reshape the cellular translation landscapes. During translation elongation, ribosomes often assemble in defined three-dimensional arrangements to form polysomes4. By mapping the intracellular organization of translating ribosomes, we show that their association into polysomes involves a local coordination mechanism that is mediated by the ribosomal protein L9. We propose that an extended conformation of L9 within polysomes mitigates collisions to facilitate translation fidelity. Our work thus demonstrates the feasibility of visualizing molecular processes at atomic detail inside cells.
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Affiliation(s)
- Liang Xue
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
- Collaboration for joint PhD degree between EMBL and Heidelberg University, Faculty of Biosciences, Heidelberg, Germany
| | - Swantje Lenz
- Chair of Bioanalytics, Technische Universität Berlin, Berlin, Germany
| | - Maria Zimmermann-Kogadeeva
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Dimitry Tegunov
- Department of Molecular Biology, Max-Planck-Institute for Biophysical Chemistry, Göttingen, Germany
| | - Patrick Cramer
- Department of Molecular Biology, Max-Planck-Institute for Biophysical Chemistry, Göttingen, Germany
| | - Peer Bork
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
- Yonsei Frontier Lab, Yonsei University, Seoul, South Korea
- Department of Bioinformatics, Biocenter, University of Würzburg, Würzburg, Germany
| | - Juri Rappsilber
- Chair of Bioanalytics, Technische Universität Berlin, Berlin, Germany
- Wellcome Centre for Cell Biology, University of Edinburgh, Edinburgh, UK
| | - Julia Mahamid
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany.
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13
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Chen Y, He X, Ma B, Liu K, Gao T, Niu W, Guo J. Noncanonical amino acid mutagenesis in response to recoding signal-enhanced quadruplet codons. Nucleic Acids Res 2022; 50:e94. [PMID: 35657094 PMCID: PMC9458425 DOI: 10.1093/nar/gkac474] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 04/13/2022] [Accepted: 04/19/2022] [Indexed: 12/01/2022] Open
Abstract
While amber suppression is the most common approach to introduce noncanonical amino acids into proteins in live cells, quadruplet codon decoding has potential to enable a greatly expanded genetic code with up to 256 new codons for protein biosynthesis. Since triplet codons are the predominant form of genetic code in nature, quadruplet codon decoding often displays limited efficiency. In this work, we exploited a new approach to significantly improve quadruplet UAGN and AGGN (N = A, U, G, C) codon decoding efficiency by using recoding signals imbedded in mRNA. With representative recoding signals, the expression level of mutant proteins containing UAGN and AGGN codons reached 48% and 98% of that of the wild-type protein, respectively. Furthermore, this strategy mitigates a common concern of reading-through endogenous stop codons with amber suppression-based system. Since synthetic recoding signals are rarely found near the endogenous UAGN and AGGN sequences, a low level of undesirable suppression is expected. Our strategy will greatly enhance the utility of noncanonical amino acid mutagenesis in live-cell studies.
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Affiliation(s)
- Yan Chen
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE 68588, USA
| | - Xinyuan He
- Department of Chemical & Biomolecular Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588, USA
| | - Bin Ma
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE 68588, USA
| | - Kun Liu
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE 68588, USA
| | - Tianyu Gao
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE 68588, USA
| | - Wei Niu
- Department of Chemical & Biomolecular Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588, USA
- The Nebraska Center for Integrated Biomolecular Communication (NCIBC), University of Nebraska-Lincoln, Lincoln, NE 68588, USA
| | - Jiantao Guo
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE 68588, USA
- The Nebraska Center for Integrated Biomolecular Communication (NCIBC), University of Nebraska-Lincoln, Lincoln, NE 68588, USA
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14
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Wright SE, Rodriguez CM, Monroe J, Xing J, Krans A, Flores BN, Barsur V, Ivanova MI, Koutmou KS, Barmada SJ, Todd PK. CGG repeats trigger translational frameshifts that generate aggregation-prone chimeric proteins. Nucleic Acids Res 2022; 50:8674-8689. [PMID: 35904811 PMCID: PMC9410890 DOI: 10.1093/nar/gkac626] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Accepted: 07/13/2022] [Indexed: 11/25/2022] Open
Abstract
CGG repeat expansions in the FMR1 5’UTR cause the neurodegenerative disease Fragile X-associated tremor/ataxia syndrome (FXTAS). These repeats form stable RNA secondary structures that support aberrant translation in the absence of an AUG start codon (RAN translation), producing aggregate-prone peptides that accumulate within intranuclear neuronal inclusions and contribute to neurotoxicity. Here, we show that the most abundant RAN translation product, FMRpolyG, is markedly less toxic when generated from a construct with a non-repetitive alternating codon sequence in place of the CGG repeat. While exploring the mechanism of this differential toxicity, we observed a +1 translational frameshift within the CGG repeat from the arginine to glycine reading frame. Frameshifts occurred within the first few translated repeats and were triggered predominantly by RNA sequence and structural features. Short chimeric R/G peptides form aggregates distinct from those formed by either pure arginine or glycine, and these chimeras induce toxicity in cultured rodent neurons. Together, this work suggests that CGG repeats support translational frameshifting and that chimeric RAN translated peptides may contribute to CGG repeat-associated toxicity in FXTAS and related disorders.
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Affiliation(s)
- Shannon E Wright
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA.,Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI 48109, USA
| | - Caitlin M Rodriguez
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA.,Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI 48109, USA.,Department of Genetics, Stanford University School of Medicine, Stanford, CA 84305, USA
| | - Jeremy Monroe
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
| | - Jiazheng Xing
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Amy Krans
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA.,VA Ann Arbor Healthcare System, Ann Arbor, MI 48105, USA
| | - Brittany N Flores
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA.,Cellular and Molecular Biology Graduate Program, University of Michigan, Ann Arbor, MI 48109, USA
| | - Venkatesha Barsur
- Department of Pathology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Magdalena I Ivanova
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA.,Biophysics Program, University of Michigan, Ann Arbor, MI 48109, USA
| | - Kristin S Koutmou
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
| | - Sami J Barmada
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Peter K Todd
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA.,VA Ann Arbor Healthcare System, Ann Arbor, MI 48105, USA
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15
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Filbeck S, Cerullo F, Pfeffer S, Joazeiro CAP. Ribosome-associated quality-control mechanisms from bacteria to humans. Mol Cell 2022; 82:1451-1466. [PMID: 35452614 PMCID: PMC9034055 DOI: 10.1016/j.molcel.2022.03.038] [Citation(s) in RCA: 46] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 03/23/2022] [Accepted: 03/28/2022] [Indexed: 11/16/2022]
Abstract
Ribosome-associated quality-control (RQC) surveys incomplete nascent polypeptides produced by interrupted translation. Central players in RQC are the human ribosome- and tRNA-binding protein, NEMF, and its orthologs, yeast Rqc2 and bacterial RqcH, which sense large ribosomal subunits obstructed with nascent chains and then promote nascent-chain proteolysis. In canonical eukaryotic RQC, NEMF stabilizes the LTN1/Listerin E3 ligase binding to obstructed ribosomal subunits for nascent-chain ubiquitylation. Furthermore, NEMF orthologs across evolution modify nascent chains by mediating C-terminal, untemplated polypeptide elongation. In eukaryotes, this process exposes ribosome-buried nascent-chain lysines, the ubiquitin acceptor sites, to LTN1. Remarkably, in both bacteria and eukaryotes, C-terminal tails also have an extra-ribosomal function as degrons. Here, we discuss recent findings on RQC mechanisms and briefly review how ribosomal stalling is sensed upstream of RQC, including via ribosome collisions, from an evolutionary perspective. Because RQC defects impair cellular fitness and cause neurodegeneration, this knowledge provides a framework for pathway-related biology and disease studies.
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Affiliation(s)
- Sebastian Filbeck
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, 69120 Heidelberg, Germany
| | - Federico Cerullo
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, 69120 Heidelberg, Germany
| | - Stefan Pfeffer
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, 69120 Heidelberg, Germany.
| | - Claudio A P Joazeiro
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, 69120 Heidelberg, Germany; Department of Molecular Medicine, Scripps Florida, Jupiter, FL 33458, USA.
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16
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Cerullo F, Filbeck S, Patil PR, Hung HC, Xu H, Vornberger J, Hofer FW, Schmitt J, Kramer G, Bukau B, Hofmann K, Pfeffer S, Joazeiro CAP. Bacterial ribosome collision sensing by a MutS DNA repair ATPase paralogue. Nature 2022; 603:509-514. [PMID: 35264791 DOI: 10.1038/s41586-022-04487-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 01/28/2022] [Indexed: 12/12/2022]
Abstract
Ribosome stalling during translation is detrimental to cellular fitness, but how this is sensed and elicits recycling of ribosomal subunits and quality control of associated mRNA and incomplete nascent chains is poorly understood1,2. Here we uncover Bacillus subtilis MutS2, a member of the conserved MutS family of ATPases that function in DNA mismatch repair3, as an unexpected ribosome-binding protein with an essential function in translational quality control. Cryo-electron microscopy analysis of affinity-purified native complexes shows that MutS2 functions in sensing collisions between stalled and translating ribosomes and suggests how ribosome collisions can serve as platforms to deploy downstream processes: MutS2 has an RNA endonuclease small MutS-related (SMR) domain, as well as an ATPase/clamp domain that is properly positioned to promote ribosomal subunit dissociation, which is a requirement both for ribosome recycling and for initiation of ribosome-associated protein quality control (RQC). Accordingly, MutS2 promotes nascent chain modification with alanine-tail degrons-an early step in RQC-in an ATPase domain-dependent manner. The relevance of these observations is underscored by evidence of strong co-occurrence of MutS2 and RQC genes across bacterial phyla. Overall, the findings demonstrate a deeply conserved role for ribosome collisions in mounting a complex response to the interruption of translation within open reading frames.
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Affiliation(s)
- Federico Cerullo
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Sebastian Filbeck
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Pratik Rajendra Patil
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Hao-Chih Hung
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Haifei Xu
- Department of Molecular Medicine, Scripps Florida, Jupiter, FL, USA
| | - Julia Vornberger
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Florian W Hofer
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Jaro Schmitt
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Guenter Kramer
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Bernd Bukau
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Kay Hofmann
- Institute for Genetics, University of Cologne, Cologne, Germany
| | - Stefan Pfeffer
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Heidelberg, Germany.
| | - Claudio A P Joazeiro
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Heidelberg, Germany. .,Department of Molecular Medicine, Scripps Florida, Jupiter, FL, USA.
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17
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Ribosome collisions induce mRNA cleavage and ribosome rescue in bacteria. Nature 2022; 603:503-508. [PMID: 35264790 DOI: 10.1038/s41586-022-04416-7] [Citation(s) in RCA: 34] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 01/07/2022] [Indexed: 01/17/2023]
Abstract
Ribosome rescue pathways recycle stalled ribosomes and target problematic mRNAs and aborted proteins for degradation1,2. In bacteria, it remains unclear how rescue pathways distinguish ribosomes stalled in the middle of a transcript from actively translating ribosomes3-6. Here, using a genetic screen in Escherichia coli, we discovered a new rescue factor that has endonuclease activity. SmrB cleaves mRNAs upstream of stalled ribosomes, allowing the ribosome rescue factor tmRNA (which acts on truncated mRNAs3) to rescue upstream ribosomes. SmrB is recruited to ribosomes and is activated by collisions. Cryo-electron microscopy structures of collided disomes from E. coli and Bacillus subtilis show distinct and conserved arrangements of individual ribosomes and the composite SmrB-binding site. These findings reveal the underlying mechanisms by which ribosome collisions trigger ribosome rescue in bacteria.
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18
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Abstract
Increased tRNA abundance and amino acid coupling generally promote increased oncogenesis. By contrast, a new study shows that in breast cancer, the leucyl-tRNA synthetase LARS suppresses transformation and tumour development by increasing tRNA-LeuCAG translation of certain tumour suppressor mRNAs.
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Affiliation(s)
- C Theresa Vincent
- Department of Microbiology, NYU Grossman School of Medicine, New York, NY, USA
- Department of Immunology, Genetics and Pathology (IGP), Uppsala University, Uppsala, Sweden
| | - Robert J Schneider
- Department of Microbiology, NYU Grossman School of Medicine, New York, NY, USA.
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19
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Cook GM, Brown K, Shang P, Li Y, Soday L, Dinan AM, Tumescheit C, Mockett APA, Fang Y, Firth AE, Brierley I. Ribosome profiling of porcine reproductive and respiratory syndrome virus reveals novel features of viral gene expression. eLife 2022; 11:e75668. [PMID: 35226596 PMCID: PMC9000960 DOI: 10.7554/elife.75668] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 02/26/2022] [Indexed: 11/13/2022] Open
Abstract
The arterivirus porcine reproductive and respiratory syndrome virus (PRRSV) causes significant economic losses to the swine industry worldwide. Here we apply ribosome profiling (RiboSeq) and parallel RNA sequencing (RNASeq) to characterise the transcriptome and translatome of both species of PRRSV and to analyse the host response to infection. We calculated programmed ribosomal frameshift (PRF) efficiency at both sites on the viral genome. This revealed the nsp2 PRF site as the second known example where temporally regulated frameshifting occurs, with increasing -2 PRF efficiency likely facilitated by accumulation of the PRF-stimulatory viral protein, nsp1β. Surprisingly, we find that PRF efficiency at the canonical ORF1ab frameshift site also increases over time, in contradiction of the common assumption that RNA structure-directed frameshift sites operate at a fixed efficiency. This has potential implications for the numerous other viruses with canonical PRF sites. Furthermore, we discovered several highly translated additional viral ORFs, the translation of which may be facilitated by multiple novel viral transcripts. For example, we found a highly expressed 125-codon ORF overlapping nsp12, which is likely translated from novel subgenomic RNA transcripts that overlap the 3' end of ORF1b. Similar transcripts were discovered for both PRRSV-1 and PRRSV-2, suggesting a potential conserved mechanism for temporally regulating expression of the 3'-proximal region of ORF1b. We also identified a highly translated, short upstream ORF in the 5' UTR, the presence of which is highly conserved amongst PRRSV-2 isolates. These findings reveal hidden complexity in the gene expression programmes of these important nidoviruses.
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Affiliation(s)
- Georgia M Cook
- Department of Pathology, University of CambridgeCambridgeUnited Kingdom
| | - Katherine Brown
- Department of Pathology, University of CambridgeCambridgeUnited Kingdom
| | - Pengcheng Shang
- Department of Diagnostic Medicine and Pathobiology, Kansas State UniversityManhattanUnited States
| | - Yanhua Li
- Department of Diagnostic Medicine and Pathobiology, Kansas State UniversityManhattanUnited States
| | - Lior Soday
- Department of Pathology, University of CambridgeCambridgeUnited Kingdom
| | - Adam M Dinan
- Department of Pathology, University of CambridgeCambridgeUnited Kingdom
| | | | | | - Ying Fang
- Department of Diagnostic Medicine and Pathobiology, Kansas State UniversityManhattanUnited States
| | - Andrew E Firth
- Department of Pathology, University of CambridgeCambridgeUnited Kingdom
| | - Ian Brierley
- Department of Pathology, University of CambridgeCambridgeUnited Kingdom
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20
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Riegger RJ, Caliskan N. Thinking Outside the Frame: Impacting Genomes Capacity by Programmed Ribosomal Frameshifting. Front Mol Biosci 2022; 9:842261. [PMID: 35281266 PMCID: PMC8915115 DOI: 10.3389/fmolb.2022.842261] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 01/26/2022] [Indexed: 01/08/2023] Open
Abstract
Translation facilitates the transfer of the genetic information stored in the genome via messenger RNAs to a functional protein and is therefore one of the most fundamental cellular processes. Programmed ribosomal frameshifting is a ubiquitous alternative translation event that is extensively used by viruses to regulate gene expression from overlapping open reading frames in a controlled manner. Recent technical advances in the translation field enabled the identification of precise mechanisms as to how and when ribosomes change the reading frame on mRNAs containing cis-acting signals. Several studies began also to illustrate that trans-acting RNA modulators can adjust the timing and efficiency of frameshifting illuminating that frameshifting can be a dynamically regulated process in cells. Here, we intend to summarize these new findings and emphasize how it fits in our current understanding of PRF mechanisms as previously described.
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Affiliation(s)
- Ricarda J. Riegger
- Helmholtz Centre for Infection Research (HZI), Helmholtz Institute for RNA-Based Infection Research (HIRI), Würzburg, Germany
- Graduate School of Life Sciences (GSLS), University of Würzburg, Würzburg, Germany
| | - Neva Caliskan
- Helmholtz Centre for Infection Research (HZI), Helmholtz Institute for RNA-Based Infection Research (HIRI), Würzburg, Germany
- Medical Faculty, University of Würzburg, Würzburg, Germany
- *Correspondence: Neva Caliskan,
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21
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Carmody PJ, Zimmer MH, Kuntz CP, Harrington HR, Duckworth K, Penn W, Mukhopadhyay S, Miller T, Schlebach J. Coordination of -1 programmed ribosomal frameshifting by transcript and nascent chain features revealed by deep mutational scanning. Nucleic Acids Res 2021; 49:12943-12954. [PMID: 34871407 PMCID: PMC8682741 DOI: 10.1093/nar/gkab1172] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 10/22/2021] [Accepted: 11/10/2021] [Indexed: 12/17/2022] Open
Abstract
Programmed ribosomal frameshifting (PRF) is a translational recoding mechanism that enables the synthesis of multiple polypeptides from a single transcript. During translation of the alphavirus structural polyprotein, the efficiency of -1PRF is coordinated by a 'slippery' sequence in the transcript, an adjacent RNA stem-loop, and a conformational transition in the nascent polypeptide chain. To characterize each of these effectors, we measured the effects of 4530 mutations on -1PRF by deep mutational scanning. While most mutations within the slip-site and stem-loop reduce the efficiency of -1PRF, the effects of mutations upstream of the slip-site are far more variable. We identify several regions where modifications of the amino acid sequence of the nascent polypeptide impact the efficiency of -1PRF. Molecular dynamics simulations of polyprotein biogenesis suggest the effects of these mutations primarily arise from their impacts on the mechanical forces that are generated by the translocon-mediated cotranslational folding of the nascent polypeptide chain. Finally, we provide evidence suggesting that the coupling between cotranslational folding and -1PRF depends on the translation kinetics upstream of the slip-site. These findings demonstrate how -1PRF is coordinated by features within both the transcript and nascent chain.
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Affiliation(s)
- Patrick J Carmody
- Department of Chemistry, Indiana University, Bloomington, IN 47405, USA
| | - Matthew H Zimmer
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Charles P Kuntz
- Department of Chemistry, Indiana University, Bloomington, IN 47405, USA
| | | | - Kate E Duckworth
- Department of Chemistry, Indiana University, Bloomington, IN 47405, USA
| | - Wesley D Penn
- Department of Chemistry, Indiana University, Bloomington, IN 47405, USA
| | | | - Thomas F Miller
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
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22
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Champagne J, Pataskar A, Blommaert N, Nagel R, Wernaart D, Ramalho S, Kenski J, Bleijerveld OB, Zaal EA, Berkers CR, Altelaar M, Peeper DS, Faller WJ, Agami R. Oncogene-dependent sloppiness in mRNA translation. Mol Cell 2021; 81:4709-4721.e9. [PMID: 34562372 DOI: 10.1016/j.molcel.2021.09.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 07/13/2021] [Accepted: 08/30/2021] [Indexed: 12/15/2022]
Abstract
mRNA translation is a highly conserved and tightly controlled mechanism for protein synthesis. Despite protein quality control mechanisms, amino acid shortage in melanoma induces aberrant proteins by ribosomal frameshifting. The extent and the underlying mechanisms related to this phenomenon are yet unknown. Here, we show that tryptophan depletion-induced ribosomal frameshifting is a widespread phenomenon in cancer. We termed this event sloppiness and strikingly observed its association with MAPK pathway hyperactivation. Sloppiness is stimulated by RAS activation in primary cells, suppressed by pharmacological inhibition of the oncogenic MAPK pathway in sloppy cells, and restored in cells with acquired resistance to MAPK pathway inhibition. Interestingly, sloppiness causes aberrant peptide presentation at the cell surface, allowing recognition and specific killing of drug-resistant cancer cells by T lymphocytes. Thus, while oncogenes empower cancer progression and aggressiveness, they also expose a vulnerability by provoking the production of aberrant peptides through sloppiness.
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Affiliation(s)
- Julien Champagne
- Division of Oncogenomics, Oncode Institute, the Netherlands Cancer Institute, Plesmanlaan 121, 1066CX Amsterdam, the Netherlands
| | - Abhijeet Pataskar
- Division of Oncogenomics, Oncode Institute, the Netherlands Cancer Institute, Plesmanlaan 121, 1066CX Amsterdam, the Netherlands
| | - Naomi Blommaert
- Division of Oncogenomics, Oncode Institute, the Netherlands Cancer Institute, Plesmanlaan 121, 1066CX Amsterdam, the Netherlands
| | - Remco Nagel
- Division of Oncogenomics, Oncode Institute, the Netherlands Cancer Institute, Plesmanlaan 121, 1066CX Amsterdam, the Netherlands
| | - Demi Wernaart
- Division of Oncogenomics, Oncode Institute, the Netherlands Cancer Institute, Plesmanlaan 121, 1066CX Amsterdam, the Netherlands
| | - Sofia Ramalho
- Division of Oncogenomics, Oncode Institute, the Netherlands Cancer Institute, Plesmanlaan 121, 1066CX Amsterdam, the Netherlands
| | - Juliana Kenski
- Division of Molecular Oncology & Immunology, Oncode Institute, The Netherlands Cancer Institute, Plesmanlaan 121, 1066CX Amsterdam, the Netherlands
| | - Onno B Bleijerveld
- Proteomics Facility, The Netherlands Cancer Institute, Plesmanlaan 121, 1066CX Amsterdam, the Netherlands
| | - Esther A Zaal
- Department of Biochemistry and Cell Biology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands; Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research, Utrecht Institute for Pharmaceutical Sciences, Utrecht University and Netherlands Proteomics Centre, Utrecht, the Netherlands
| | - Celia R Berkers
- Department of Biochemistry and Cell Biology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands; Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research, Utrecht Institute for Pharmaceutical Sciences, Utrecht University and Netherlands Proteomics Centre, Utrecht, the Netherlands
| | - Maarten Altelaar
- Proteomics Facility, The Netherlands Cancer Institute, Plesmanlaan 121, 1066CX Amsterdam, the Netherlands; Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research, Utrecht Institute for Pharmaceutical Sciences, Utrecht University and Netherlands Proteomics Centre, Utrecht, the Netherlands
| | - Daniel S Peeper
- Division of Molecular Oncology & Immunology, Oncode Institute, The Netherlands Cancer Institute, Plesmanlaan 121, 1066CX Amsterdam, the Netherlands
| | - William J Faller
- Division of Oncogenomics, Oncode Institute, the Netherlands Cancer Institute, Plesmanlaan 121, 1066CX Amsterdam, the Netherlands
| | - Reuven Agami
- Division of Oncogenomics, Oncode Institute, the Netherlands Cancer Institute, Plesmanlaan 121, 1066CX Amsterdam, the Netherlands; Erasmus MC, Rotterdam University, Rotterdam, the Netherlands.
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23
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Hill CH, Cook GM, Napthine S, Kibe A, Brown K, Caliskan N, Firth AE, Graham SC, Brierley I. Investigating molecular mechanisms of 2A-stimulated ribosomal pausing and frameshifting in Theilovirus. Nucleic Acids Res 2021; 49:11938-11958. [PMID: 34751406 PMCID: PMC8599813 DOI: 10.1093/nar/gkab969] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2021] [Revised: 10/01/2021] [Accepted: 10/06/2021] [Indexed: 12/02/2022] Open
Abstract
The 2A protein of Theiler's murine encephalomyelitis virus (TMEV) acts as a switch to stimulate programmed -1 ribosomal frameshifting (PRF) during infection. Here, we present the X-ray crystal structure of TMEV 2A and define how it recognises the stimulatory RNA element. We demonstrate a critical role for bases upstream of the originally predicted stem-loop, providing evidence for a pseudoknot-like conformation and suggesting that the recognition of this pseudoknot by beta-shell proteins is a conserved feature in cardioviruses. Through examination of PRF in TMEV-infected cells by ribosome profiling, we identify a series of ribosomal pauses around the site of PRF induced by the 2A-pseudoknot complex. Careful normalisation of ribosomal profiling data with a 2A knockout virus facilitated the identification, through disome analysis, of ribosome stacking at the TMEV frameshifting signal. These experiments provide unparalleled detail of the molecular mechanisms underpinning Theilovirus protein-stimulated frameshifting.
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Affiliation(s)
- Chris H Hill
- Division of Virology, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
| | - Georgia M Cook
- Division of Virology, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
| | - Sawsan Napthine
- Division of Virology, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
| | - Anuja Kibe
- Helmholtz Institute for RNA-based Infection Research (HIRI), Josef-Schneider-Straße 2/D15, 97080 Würzburg, Germany
| | - Katherine Brown
- Division of Virology, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
| | - Neva Caliskan
- Helmholtz Institute for RNA-based Infection Research (HIRI), Josef-Schneider-Straße 2/D15, 97080 Würzburg, Germany
- Medical Faculty, Julius-Maximilians University Würzburg, 97074 Würzburg, Germany
| | - Andrew E Firth
- Division of Virology, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
| | - Stephen C Graham
- Division of Virology, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
| | - Ian Brierley
- Division of Virology, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
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24
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Masuda I, Hwang JY, Christian T, Maharjan S, Mohammad F, Gamper H, Buskirk AR, Hou YM. Loss of N1-methylation of G37 in tRNA induces ribosome stalling and reprograms gene expression. eLife 2021; 10:70619. [PMID: 34382933 PMCID: PMC8384417 DOI: 10.7554/elife.70619] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2021] [Accepted: 08/09/2021] [Indexed: 01/20/2023] Open
Abstract
N1-methylation of G37 is required for a subset of tRNAs to maintain the translational reading-frame. While loss of m1G37 increases ribosomal +1 frameshifting, whether it incurs additional translational defects is unknown. Here, we address this question by applying ribosome profiling to gain a genome-wide view of the effects of m1G37 deficiency on protein synthesis. Using E coli as a model, we show that m1G37 deficiency induces ribosome stalling at codons that are normally translated by m1G37-containing tRNAs. Stalling occurs during decoding of affected codons at the ribosomal A site, indicating a distinct mechanism than that of +1 frameshifting, which occurs after the affected codons leave the A site. Enzyme- and cell-based assays show that m1G37 deficiency reduces tRNA aminoacylation and in some cases peptide-bond formation. We observe changes of gene expression in m1G37 deficiency similar to those in the stringent response that is typically induced by deficiency of amino acids. This work demonstrates a previously unrecognized function of m1G37 that emphasizes its role throughout the entire elongation cycle of protein synthesis, providing new insight into its essentiality for bacterial growth and survival.
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Affiliation(s)
- Isao Masuda
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, United States
| | - Jae-Yeon Hwang
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Thomas Christian
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, United States
| | - Sunita Maharjan
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, United States
| | - Fuad Mohammad
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Howard Gamper
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, United States
| | - Allen R Buskirk
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Ya-Ming Hou
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, United States
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25
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Hsu CF, Chang KC, Chen YL, Hsieh PS, Lee AI, Tu JY, Chen YT, Wen JD. Formation of frameshift-stimulating RNA pseudoknots is facilitated by remodeling of their folding intermediates. Nucleic Acids Res 2021; 49:6941-6957. [PMID: 34161580 PMCID: PMC8266650 DOI: 10.1093/nar/gkab512] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 05/27/2021] [Accepted: 06/04/2021] [Indexed: 12/15/2022] Open
Abstract
Programmed –1 ribosomal frameshifting is an essential regulation mechanism of translation in viruses and bacteria. It is stimulated by mRNA structures inside the coding region. As the structure is unfolded repeatedly by consecutive translating ribosomes, whether it can refold properly each time is important in performing its function. By using single-molecule approaches and molecular dynamics simulations, we found that a frameshift-stimulating RNA pseudoknot folds sequentially through its upstream stem S1 and downstream stem S2. In this pathway, S2 folds from the downstream side and tends to be trapped in intermediates. By masking the last few nucleotides to mimic their gradual emergence from translating ribosomes, S2 can be directed to fold from the upstream region. The results show that the intermediates are greatly suppressed, suggesting that mRNA refolding may be modulated by ribosomes. Moreover, masking the first few nucleotides of S1 favors the folding from S2 and yields native pseudoknots, which are stable enough to retrieve the masked nucleotides. We hypothesize that translating ribosomes can remodel an intermediate mRNA structure into a stable conformation, which may in turn stimulate backward slippage of the ribosome. This supports an interactive model of ribosomal frameshifting and gives an insightful account addressing previous experimental observations.
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Affiliation(s)
- Chiung-Fang Hsu
- Institute of Molecular and Cellular Biology, National Taiwan University, Taipei 10617, Taiwan
| | - Kai-Chun Chang
- Institute of Molecular and Cellular Biology, National Taiwan University, Taipei 10617, Taiwan
| | - Yi-Lan Chen
- Genome and Systems Biology Degree Program, National Taiwan University and Academia Sinica, Taipei 10617, Taiwan
| | - Po-Szu Hsieh
- Institute of Molecular and Cellular Biology, National Taiwan University, Taipei 10617, Taiwan
| | - An-I Lee
- Institute of Molecular and Cellular Biology, National Taiwan University, Taipei 10617, Taiwan
| | - Jui-Yun Tu
- Institute of Molecular and Cellular Biology, National Taiwan University, Taipei 10617, Taiwan
| | - Yu-Ting Chen
- Institute of Molecular and Cellular Biology, National Taiwan University, Taipei 10617, Taiwan
| | - Jin-Der Wen
- Institute of Molecular and Cellular Biology, National Taiwan University, Taipei 10617, Taiwan.,Genome and Systems Biology Degree Program, National Taiwan University and Academia Sinica, Taipei 10617, Taiwan
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26
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Atkins JF, O’Connor KM, Bhatt PR, Loughran G. From Recoding to Peptides for MHC Class I Immune Display: Enriching Viral Expression, Virus Vulnerability and Virus Evasion. Viruses 2021; 13:1251. [PMID: 34199077 PMCID: PMC8310308 DOI: 10.3390/v13071251] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 06/11/2021] [Accepted: 06/19/2021] [Indexed: 01/02/2023] Open
Abstract
Many viruses, especially RNA viruses, utilize programmed ribosomal frameshifting and/or stop codon readthrough in their expression, and in the decoding of a few a UGA is dynamically redefined to specify selenocysteine. This recoding can effectively increase viral coding capacity and generate a set ratio of products with the same N-terminal domain(s) but different C-terminal domains. Recoding can also be regulatory or generate a product with the non-universal 21st directly encoded amino acid. Selection for translation speed in the expression of many viruses at the expense of fidelity creates host immune defensive opportunities. In contrast to host opportunism, certain viruses, including some persistent viruses, utilize recoding or adventitious frameshifting as part of their strategy to evade an immune response or specific drugs. Several instances of recoding in small intensively studied viruses escaped detection for many years and their identification resolved dilemmas. The fundamental importance of ribosome ratcheting is consistent with the initial strong view of invariant triplet decoding which however did not foresee the possibility of transitory anticodon:codon dissociation. Deep level dynamics and structural understanding of recoding is underway, and a high level structure relevant to the frameshifting required for expression of the SARS CoV-2 genome has just been determined.
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Affiliation(s)
- John F. Atkins
- Schools of Biochemistry and Microbiology, University College Cork, T12 XF62 Cork, Ireland; (K.M.O.); (P.R.B.); (G.L.)
| | - Kate M. O’Connor
- Schools of Biochemistry and Microbiology, University College Cork, T12 XF62 Cork, Ireland; (K.M.O.); (P.R.B.); (G.L.)
| | - Pramod R. Bhatt
- Schools of Biochemistry and Microbiology, University College Cork, T12 XF62 Cork, Ireland; (K.M.O.); (P.R.B.); (G.L.)
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, 8093 Zurich, Switzerland
| | - Gary Loughran
- Schools of Biochemistry and Microbiology, University College Cork, T12 XF62 Cork, Ireland; (K.M.O.); (P.R.B.); (G.L.)
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27
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Nikolaeva DD, Gelfand MS, Garushyants SK. Simplification of Ribosomes in Bacteria with Tiny Genomes. Mol Biol Evol 2021; 38:58-66. [PMID: 32681797 PMCID: PMC7782861 DOI: 10.1093/molbev/msaa184] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The ribosome is an essential cellular machine performing protein biosynthesis. Its structure and composition are highly conserved in all species. However, some bacteria have been reported to have an incomplete set of ribosomal proteins. We have analyzed ribosomal protein composition in 214 small bacterial genomes (<1 Mb) and found that although the ribosome composition is fairly stable, some ribosomal proteins may be absent, especially in bacteria with dramatically reduced genomes. The protein composition of the large subunit is less conserved than that of the small subunit. We have identified the set of frequently lost ribosomal proteins and demonstrated that they tend to be positioned on the ribosome surface and have fewer contacts to other ribosome components. Moreover, some proteins are lost in an evolutionary correlated manner. The reduction of ribosomal RNA is also common, with deletions mostly occurring in free loops. Finally, the loss of the anti-Shine-Dalgarno sequence is associated with the loss of a higher number of ribosomal proteins.
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Affiliation(s)
- Daria D Nikolaeva
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, Russia.,Institute for Information Transmission Problems (Kharkevich Institute), Moscow, Russia
| | - Mikhail S Gelfand
- Institute for Information Transmission Problems (Kharkevich Institute), Moscow, Russia.,Center of Life Sciences, Skolkovo Institute of Science and Technology, Moscow, Russia
| | - Sofya K Garushyants
- Institute for Information Transmission Problems (Kharkevich Institute), Moscow, Russia
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28
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Abstract
By evolving strains of E. coli that hyper-resist sedimentation, we discovered an uncharacterized mechanism that bacteria can use to remain in suspension indefinitely without expending energy. This unusual phenotype was traced to the anchoring of long colanic acid polymers (CAP) that project from the cell surface. Although each characterized mutant activated this same mechanism, the genes responsible and the strengths of the phenotypes varied. Mutations in rcsC, lpp, igaA, or the yjbEFGH operon were sufficient to stimulate sedimentation resistance, while mutations altering the cps promoter, cdgI, or yjbF provided phenotypic enhancements. The sedimentation resistances changed in response to temperature, growth phase, and carbon source and each mutant exhibited significantly reduced biofilm formation. We discovered that the degree of colony mucoidy exhibited by these mutants was not related to the degree of Rcs pathways activation or to the amount of CAP that was produced; rather, it was related to the fraction of CAP that was shed as a true exopolysaccharide. Therefore, these and other mutations that activate this phenotype are likely to be absent from genetic screens that relied on centrifugation to harvest bacteria. We also found that this anchored CAP form is not linked to LPS cores and may not be attached to the outer membrane.IMPORTANCEBacteria can partition in aqueous environments between surface-dwelling, planktonic, sedimentary, and biofilm forms. Residence in each location provides an advantage depending on nutritional and environmental stresses and a community of a single species is often observed to be distributed throughout two or more of these niches. Another adaptive strategy is to produce an extracellular capsule, which provides an environmental shield for the microbe and can allow escape from predators and immune systems. We discovered that bacteria can either shed or stably anchor capsules to dramatically alter their propensity to sediment. The degree to which the bacteria anchor their capsule is controlled by a stress sensing system, suggesting that anchoring may be used as an adaptive response to severe environmental challenges.
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29
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Nikolaeva DD, Gelfand MS, Garushyants SK. Simplification of Ribosomes in Bacteria with Tiny Genomes. Mol Biol Evol 2021. [PMID: 32681797 DOI: 10.1101/755876] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2023] Open
Abstract
The ribosome is an essential cellular machine performing protein biosynthesis. Its structure and composition are highly conserved in all species. However, some bacteria have been reported to have an incomplete set of ribosomal proteins. We have analyzed ribosomal protein composition in 214 small bacterial genomes (<1 Mb) and found that although the ribosome composition is fairly stable, some ribosomal proteins may be absent, especially in bacteria with dramatically reduced genomes. The protein composition of the large subunit is less conserved than that of the small subunit. We have identified the set of frequently lost ribosomal proteins and demonstrated that they tend to be positioned on the ribosome surface and have fewer contacts to other ribosome components. Moreover, some proteins are lost in an evolutionary correlated manner. The reduction of ribosomal RNA is also common, with deletions mostly occurring in free loops. Finally, the loss of the anti-Shine-Dalgarno sequence is associated with the loss of a higher number of ribosomal proteins.
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Affiliation(s)
- Daria D Nikolaeva
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, Russia
- Institute for Information Transmission Problems (Kharkevich Institute), Moscow, Russia
| | - Mikhail S Gelfand
- Institute for Information Transmission Problems (Kharkevich Institute), Moscow, Russia
- Center of Life Sciences, Skolkovo Institute of Science and Technology, Moscow, Russia
| | - Sofya K Garushyants
- Institute for Information Transmission Problems (Kharkevich Institute), Moscow, Russia
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30
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Nersisyan L, Ropat M, Pelechano V. Improved computational analysis of ribosome dynamics from 5'P degradome data using fivepseq. NAR Genom Bioinform 2020; 2:lqaa099. [PMID: 33575643 PMCID: PMC7685019 DOI: 10.1093/nargab/lqaa099] [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: 09/10/2020] [Revised: 10/20/2020] [Accepted: 11/03/2020] [Indexed: 02/07/2023] Open
Abstract
In eukaryotes, 5′–3′ co-translation degradation machinery follows the last translating ribosome providing an in vivo footprint of its position. Thus, 5′ monophosphorylated (5′P) degradome sequencing, in addition to informing about RNA decay, also provides information regarding ribosome dynamics. Multiple experimental methods have been developed to investigate the mRNA degradome; however, computational tools for their reproducible analysis are lacking. Here, we present fivepseq: an easy-to-use application for analysis and interactive visualization of 5′P degradome data. This tool performs both metagene- and gene-specific analysis, and enables easy investigation of codon-specific ribosome pauses. To demonstrate its ability to provide new biological information, we investigate gene-specific ribosome pauses in Saccharomyces cerevisiae after eIF5A depletion. In addition to identifying pauses at expected codon motifs, we identify multiple genes with strain-specific degradation frameshifts. To show its wide applicability, we investigate 5′P degradome from Arabidopsis thaliana and discover both motif-specific ribosome protection associated with particular developmental stages and generally increased ribosome protection at termination level associated with age. Our work shows how the use of improved analysis tools for the study of 5′P degradome can significantly increase the biological information that can be derived from such datasets and facilitate its reproducible analysis.
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Affiliation(s)
- Lilit Nersisyan
- SciLifeLab, Department of Microbiology, Tumor and Cell Biology. Karolinska Institutet, Solna 171 65, Sweden
| | - Maria Ropat
- SciLifeLab, Department of Microbiology, Tumor and Cell Biology. Karolinska Institutet, Solna 171 65, Sweden
| | - Vicent Pelechano
- SciLifeLab, Department of Microbiology, Tumor and Cell Biology. Karolinska Institutet, Solna 171 65, Sweden
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31
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A cellular handbook for collided ribosomes: surveillance pathways and collision types. Curr Genet 2020; 67:19-26. [PMID: 33044589 DOI: 10.1007/s00294-020-01111-w] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Revised: 09/12/2020] [Accepted: 09/18/2020] [Indexed: 12/29/2022]
Abstract
Translating ribosomes slow down or completely stall when they encounter obstacles on mRNAs. Such events can lead to ribosomes colliding with each other and forming complexes of two (disome), three (trisome) or more ribosomes. While these events can activate surveillance pathways, it has been unclear if collisions are common on endogenous mRNAs and whether they are usually detected by these cellular pathways. Recent genome-wide surveys of collisions revealed widespread distribution of disomes and trisomes across endogenous mRNAs in eukaryotic cells. Several studies further hinted that the recognition of collisions and response to them by multiple surveillance pathways depend on the context and duration of the ribosome stalling. This review considers recent efforts in the identification of endogenous ribosome collisions and cellular pathways dedicated to sense their severity. We further discuss the potential role of collided ribosomes in modulating co-translational events and contributing to cellular homeostasis.
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32
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Disome and Trisome Profiling Reveal Genome-wide Targets of Ribosome Quality Control. Mol Cell 2020; 79:588-602.e6. [PMID: 32615089 DOI: 10.1016/j.molcel.2020.06.010] [Citation(s) in RCA: 89] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 04/07/2020] [Accepted: 06/02/2020] [Indexed: 01/18/2023]
Abstract
The ribosome-associated protein quality control (RQC) system that resolves stalled translation events is activated when ribosomes collide and form disome, trisome, or higher-order complexes. However, it is unclear whether this system distinguishes collision complexes formed on defective mRNAs from those with functional roles on endogenous transcripts. Here, we performed disome and trisome footprint profiling in yeast and found collisions were enriched on diverse sequence motifs known to slow translation. When 60S recycling was inhibited, disomes accumulated at stop codons and could move into the 3' UTR to reinitiate translation. The ubiquitin ligase and RQC factor Hel2/ZNF598 generally recognized collisions but did not induce degradation of endogenous transcripts. However, loss of Hel2 triggered the integrated stress response, via phosphorylation of eIF2α, thus linking these pathways. Our results suggest that Hel2 has a role in sensing ribosome collisions on endogenous mRNAs, and such events may be important for cellular homeostasis.
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33
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Penn WD, Harrington HR, Schlebach JP, Mukhopadhyay S. Regulators of Viral Frameshifting: More Than RNA Influences Translation Events. Annu Rev Virol 2020; 7:219-238. [PMID: 32600156 DOI: 10.1146/annurev-virology-012120-101548] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Programmed ribosomal frameshifting (PRF) is a conserved translational recoding mechanism found in all branches of life and viruses. In bacteria, archaea, and eukaryotes PRF is used to downregulate protein production by inducing a premature termination of translation, which triggers messenger RNA (mRNA) decay. In viruses, PRF is used to drive the production of a new protein while downregulating the production of another protein, thus maintaining a stoichiometry optimal for productive infection. Traditionally, PRF motifs have been defined by the characteristics of two cis elements: a slippery heptanucleotide sequence followed by an RNA pseudoknot or stem-loop within the mRNA. Recently, additional cis and new trans elements have been identified that regulate PRF in both host and viral translation. These additional factors suggest PRF is an evolutionarily conserved process whose function and regulation we are just beginning to understand.
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Affiliation(s)
- Wesley D Penn
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, USA
| | - Haley R Harrington
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, USA
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34
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Tollerson R, Ibba M. Translational regulation of environmental adaptation in bacteria. J Biol Chem 2020; 295:10434-10445. [PMID: 32518156 DOI: 10.1074/jbc.rev120.012742] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Revised: 06/08/2020] [Indexed: 01/26/2023] Open
Abstract
Bacteria must rapidly respond to both intracellular and environmental changes to survive. One critical mechanism to rapidly detect and adapt to changes in environmental conditions is control of gene expression at the level of protein synthesis. At each of the three major steps of translation-initiation, elongation, and termination-cells use stimuli to tune translation rate and cellular protein concentrations. For example, changes in nutrient concentrations in the cell can lead to translational responses involving mechanisms such as dynamic folding of riboswitches during translation initiation or the synthesis of alarmones, which drastically alter cell physiology. Moreover, the cell can fine-tune the levels of specific protein products using programmed ribosome pausing or inducing frameshifting. Recent studies have improved understanding and revealed greater complexity regarding long-standing paradigms describing key regulatory steps of translation such as start-site selection and the coupling of transcription and translation. In this review, we describe how bacteria regulate their gene expression at the three translational steps and discuss how translation is used to detect and respond to changes in the cellular environment. Finally, we appraise the costs and benefits of regulation at the translational level in bacteria.
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Affiliation(s)
- Rodney Tollerson
- Department of Microbiology and Center for RNA Biology, Ohio State University, Columbus, Ohio, USA
| | - Michael Ibba
- Department of Microbiology and Center for RNA Biology, Ohio State University, Columbus, Ohio, USA
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35
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O'Loughlin S, Capece MC, Klimova M, Wills NM, Coakley A, Samatova E, O'Connor PBF, Loughran G, Weissman JS, Baranov PV, Rodnina MV, Puglisi JD, Atkins JF. Polysomes Bypass a 50-Nucleotide Coding Gap Less Efficiently Than Monosomes Due to Attenuation of a 5' mRNA Stem-Loop and Enhanced Drop-off. J Mol Biol 2020; 432:4369-4387. [PMID: 32454154 PMCID: PMC7245268 DOI: 10.1016/j.jmb.2020.05.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 05/08/2020] [Accepted: 05/11/2020] [Indexed: 01/03/2023]
Abstract
Efficient translational bypassing of a 50-nt non-coding gap in a phage T4 topoisomerase subunit gene (gp60) requires several recoding signals. Here we investigate the function of the mRNA stem–loop 5′ of the take-off codon, as well as the importance of ribosome loading density on the mRNA for efficient bypassing. We show that polysomes are less efficient at mediating bypassing than monosomes, both in vitro and in vivo, due to their preventing formation of a stem–loop 5′ of the take-off codon and allowing greater peptidyl-tRNA drop off. A ribosome profiling analysis of phage T4-infected Escherichia coli yielded protected mRNA fragments within the normal size range derived from ribosomes stalled at the take-off codon. However, ribosomes at this position also yielded some 53-nucleotide fragments, 16 longer. These were due to protection of the nucleotides that form the 5′ stem–loop. NMR shows that the 5′ stem–loop is highly dynamic. The importance of different nucleotides in the 5′ stem–loop is revealed by mutagenesis studies. These data highlight the significance of the 5′ stem–loop for the 50-nt bypassing and further enhance appreciation of relevance of the extent of ribosome loading for recoding. Monosomes are more efficient than polysome in mediating 50-nt translational bypassing. A 5′ mRNA stem–loop facilitates translational bypassing by monosomes. Ribosome profiling yields an extra-long, 53-nt, protected fragment of mRNA.
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Affiliation(s)
- Sinéad O'Loughlin
- School of Biochemistry, University College Cork, Western Gateway Building, Western Road, Cork, T12 XF62, Ireland; School of Microbiology, University College Cork, Western Gateway Building, Western Road, Cork, T12 YT57, Ireland
| | - Mark C Capece
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305-4090, USA
| | - Mariia Klimova
- Department of Physical Biochemistry, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | - Norma M Wills
- Department of Human Genetics, University of Utah, Salt Lake City, UT 84112-5330, USA
| | - Arthur Coakley
- School of Biochemistry, University College Cork, Western Gateway Building, Western Road, Cork, T12 XF62, Ireland
| | - Ekaterina Samatova
- Department of Physical Biochemistry, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | - Patrick B F O'Connor
- School of Biochemistry, University College Cork, Western Gateway Building, Western Road, Cork, T12 XF62, Ireland
| | - Gary Loughran
- School of Biochemistry, University College Cork, Western Gateway Building, Western Road, Cork, T12 XF62, Ireland
| | - Jonathan S Weissman
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Pavel V Baranov
- School of Biochemistry, University College Cork, Western Gateway Building, Western Road, Cork, T12 XF62, Ireland; Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, RAS, Moscow 117997, Russia
| | - Marina V Rodnina
- Department of Physical Biochemistry, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | - Joseph D Puglisi
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305-4090, USA
| | - John F Atkins
- School of Biochemistry, University College Cork, Western Gateway Building, Western Road, Cork, T12 XF62, Ireland; School of Microbiology, University College Cork, Western Gateway Building, Western Road, Cork, T12 YT57, Ireland; Department of Human Genetics, University of Utah, Salt Lake City, UT 84112-5330, USA.
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36
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Ribosome Dimerization Protects the Small Subunit. J Bacteriol 2020; 202:JB.00009-20. [PMID: 32123037 PMCID: PMC7186458 DOI: 10.1128/jb.00009-20] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Accepted: 02/25/2020] [Indexed: 01/21/2023] Open
Abstract
When nutrients become scarce, bacteria can enter an extended state of quiescence. A major challenge of this state is how to preserve ribosomes for the return to favorable conditions. Here, we show that the ribosome dimerization protein hibernation-promoting factor (HPF) functions to protect essential ribosomal proteins. Ribosomes isolated from strains lacking HPF (Δhpf) or encoding a mutant allele of HPF that binds the ribosome but does not mediate dimerization were substantially depleted of the small subunit proteins S2 and S3. Strikingly, these proteins are located directly at the ribosome dimer interface. We used single-particle cryo-electron microscopy (cryo-EM) to further characterize these ribosomes and observed that a high percentage of ribosomes were missing S2, S3, or both. These data support a model in which the ribosome dimerization activity of HPF evolved to protect labile proteins that are essential for ribosome function. HPF is almost universally conserved in bacteria, and HPF deletions in diverse species exhibit decreased viability during starvation. Our data provide mechanistic insight into this phenotype and establish a mechanism for how HPF protects ribosomes during quiescence.IMPORTANCE The formation of ribosome dimers during periods of dormancy is widespread among bacteria. Dimerization is typically mediated by a single protein, hibernation-promoting factor (HPF). Bacteria lacking HPF exhibit strong defects in viability and pathogenesis and, in some species, extreme loss of rRNA. The mechanistic basis of these phenotypes has not been determined. Here, we report that HPF from the Gram-positive bacterium Bacillus subtilis preserves ribosomes by preventing the loss of essential ribosomal proteins at the dimer interface. This protection may explain phenotypes associated with the loss of HPF, since ribosome protection would aid survival during nutrient limitation and impart a strong selective advantage when the bacterial cell rapidly reinitiates growth in the presence of sufficient nutrients.
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37
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Tesina P, Lessen LN, Buschauer R, Cheng J, Wu CC, Berninghausen O, Buskirk AR, Becker T, Beckmann R, Green R. Molecular mechanism of translational stalling by inhibitory codon combinations and poly(A) tracts. EMBO J 2020; 39:e103365. [PMID: 31858614 PMCID: PMC6996574 DOI: 10.15252/embj.2019103365] [Citation(s) in RCA: 93] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 11/08/2019] [Accepted: 12/06/2019] [Indexed: 12/24/2022] Open
Abstract
Inhibitory codon pairs and poly(A) tracts within the translated mRNA cause ribosome stalling and reduce protein output. The molecular mechanisms that drive these stalling events, however, are still unknown. Here, we use a combination of in vitro biochemistry, ribosome profiling, and cryo-EM to define molecular mechanisms that lead to these ribosome stalls. First, we use an in vitro reconstituted yeast translation system to demonstrate that inhibitory codon pairs slow elongation rates which are partially rescued by increased tRNA concentration or by an artificial tRNA not dependent on wobble base-pairing. Ribosome profiling data extend these observations by revealing that paused ribosomes with empty A sites are enriched on these sequences. Cryo-EM structures of stalled ribosomes provide a structural explanation for the observed effects by showing decoding-incompatible conformations of mRNA in the A sites of all studied stall- and collision-inducing sequences. Interestingly, in the case of poly(A) tracts, the inhibitory conformation of the mRNA in the A site involves a nucleotide stacking array. Together, these data demonstrate a novel mRNA-induced mechanisms of translational stalling in eukaryotic ribosomes.
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Affiliation(s)
- Petr Tesina
- Gene Center and Center for Integrated Protein Science MunichDepartment of BiochemistryUniversity of MunichMunichGermany
| | - Laura N Lessen
- Program in Molecular BiophysicsJohns Hopkins University School of MedicineBaltimoreMDUSA
- Department of Molecular Biology and GeneticsJohns Hopkins University School of MedicineBaltimoreMDUSA
| | - Robert Buschauer
- Gene Center and Center for Integrated Protein Science MunichDepartment of BiochemistryUniversity of MunichMunichGermany
| | - Jingdong Cheng
- Gene Center and Center for Integrated Protein Science MunichDepartment of BiochemistryUniversity of MunichMunichGermany
| | - Colin Chih‐Chien Wu
- Department of Molecular Biology and GeneticsJohns Hopkins University School of MedicineBaltimoreMDUSA
- Howard Hughes Medical InstituteJohns Hopkins University School of MedicineBaltimoreMDUSA
| | - Otto Berninghausen
- Gene Center and Center for Integrated Protein Science MunichDepartment of BiochemistryUniversity of MunichMunichGermany
| | - Allen R Buskirk
- Department of Molecular Biology and GeneticsJohns Hopkins University School of MedicineBaltimoreMDUSA
| | - Thomas Becker
- Gene Center and Center for Integrated Protein Science MunichDepartment of BiochemistryUniversity of MunichMunichGermany
| | - Roland Beckmann
- Gene Center and Center for Integrated Protein Science MunichDepartment of BiochemistryUniversity of MunichMunichGermany
| | - Rachel Green
- Department of Molecular Biology and GeneticsJohns Hopkins University School of MedicineBaltimoreMDUSA
- Howard Hughes Medical InstituteJohns Hopkins University School of MedicineBaltimoreMDUSA
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