1
|
Ren G, Gu X, Zhang L, Gong S, Song S, Chen S, Chen Z, Wang X, Li Z, Zhou Y, Li L, Yang J, Lai F, Dang Y. Ribosomal frameshifting at normal codon repeats recodes functional chimeric proteins in human. Nucleic Acids Res 2024; 52:2463-2479. [PMID: 38281188 PMCID: PMC10954444 DOI: 10.1093/nar/gkae035] [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: 08/10/2023] [Revised: 01/04/2024] [Accepted: 01/10/2024] [Indexed: 01/30/2024] Open
Abstract
Ribosomal frameshifting refers to the process that ribosomes slip into +1 or -1 reading frame, thus produce chimeric trans-frame proteins. In viruses and bacteria, programmed ribosomal frameshifting can produce essential trans-frame proteins for viral replication or regulation of other biological processes. In humans, however, functional trans-frame protein derived from ribosomal frameshifting is scarcely documented. Combining multiple assays, we show that short codon repeats could act as cis-acting elements that stimulate ribosomal frameshifting in humans, abbreviated as CRFS hereafter. Using proteomic analyses, we identified many putative CRFS events from 32 normal human tissues supported by trans-frame peptides positioned at codon repeats. Finally, we show a CRFS-derived trans-frame protein (HDAC1-FS) functions by antagonizing the activities of HDAC1, thus affecting cell migration and apoptosis. These data suggest a novel type of translational recoding associated with codon repeats, which may expand the coding capacity of mRNA and diversify the regulation in human.
Collapse
Affiliation(s)
- Guiping Ren
- State Key Laboratory for Conservation and Utilization of Bio-Resource in Yunnan, Key Laboratory for Southwest Microbial Diversity of the Ministry of Education, Yunnan Key Laboratory of Cell Metabolism and Diseases, Center for Life Science, School of Life Sciences, Yunnan University, Kunming 650021, China
- Southwest United Graduate School, Kunming650092, China
| | - Xiaoqian Gu
- State Key Laboratory for Conservation and Utilization of Bio-Resource in Yunnan, Key Laboratory for Southwest Microbial Diversity of the Ministry of Education, Yunnan Key Laboratory of Cell Metabolism and Diseases, Center for Life Science, School of Life Sciences, Yunnan University, Kunming 650021, China
- Southwest United Graduate School, Kunming650092, China
| | - Lu Zhang
- State Key Laboratory for Conservation and Utilization of Bio-Resource in Yunnan, Key Laboratory for Southwest Microbial Diversity of the Ministry of Education, Yunnan Key Laboratory of Cell Metabolism and Diseases, Center for Life Science, School of Life Sciences, Yunnan University, Kunming 650021, China
- Southwest United Graduate School, Kunming650092, China
| | - Shimin Gong
- State Key Laboratory for Conservation and Utilization of Bio-Resource in Yunnan, Key Laboratory for Southwest Microbial Diversity of the Ministry of Education, Yunnan Key Laboratory of Cell Metabolism and Diseases, Center for Life Science, School of Life Sciences, Yunnan University, Kunming 650021, China
- Southwest United Graduate School, Kunming650092, China
| | - Shuang Song
- State Key Laboratory for Conservation and Utilization of Bio-Resource in Yunnan, Key Laboratory for Southwest Microbial Diversity of the Ministry of Education, Yunnan Key Laboratory of Cell Metabolism and Diseases, Center for Life Science, School of Life Sciences, Yunnan University, Kunming 650021, China
- Southwest United Graduate School, Kunming650092, China
| | - Shunkai Chen
- State Key Laboratory for Conservation and Utilization of Bio-Resource in Yunnan, Key Laboratory for Southwest Microbial Diversity of the Ministry of Education, Yunnan Key Laboratory of Cell Metabolism and Diseases, Center for Life Science, School of Life Sciences, Yunnan University, Kunming 650021, China
- Southwest United Graduate School, Kunming650092, China
| | - Zhenjing Chen
- State Key Laboratory for Conservation and Utilization of Bio-Resource in Yunnan, Key Laboratory for Southwest Microbial Diversity of the Ministry of Education, Yunnan Key Laboratory of Cell Metabolism and Diseases, Center for Life Science, School of Life Sciences, Yunnan University, Kunming 650021, China
- Southwest United Graduate School, Kunming650092, China
| | - Xiaoyan Wang
- State Key Laboratory for Conservation and Utilization of Bio-Resource in Yunnan, Key Laboratory for Southwest Microbial Diversity of the Ministry of Education, Yunnan Key Laboratory of Cell Metabolism and Diseases, Center for Life Science, School of Life Sciences, Yunnan University, Kunming 650021, China
- Southwest United Graduate School, Kunming650092, China
| | - Zhanbiao Li
- State Key Laboratory for Conservation and Utilization of Bio-Resource in Yunnan, Key Laboratory for Southwest Microbial Diversity of the Ministry of Education, Yunnan Key Laboratory of Cell Metabolism and Diseases, Center for Life Science, School of Life Sciences, Yunnan University, Kunming 650021, China
- Southwest United Graduate School, Kunming650092, China
| | - Yingshui Zhou
- State Key Laboratory for Conservation and Utilization of Bio-Resource in Yunnan, Key Laboratory for Southwest Microbial Diversity of the Ministry of Education, Yunnan Key Laboratory of Cell Metabolism and Diseases, Center for Life Science, School of Life Sciences, Yunnan University, Kunming 650021, China
- Southwest United Graduate School, Kunming650092, China
| | - Longxi Li
- State Key Laboratory for Conservation and Utilization of Bio-Resource in Yunnan, Key Laboratory for Southwest Microbial Diversity of the Ministry of Education, Yunnan Key Laboratory of Cell Metabolism and Diseases, Center for Life Science, School of Life Sciences, Yunnan University, Kunming 650021, China
- Southwest United Graduate School, Kunming650092, China
| | - Jiao Yang
- State Key Laboratory for Conservation and Utilization of Bio-Resource in Yunnan, Key Laboratory for Southwest Microbial Diversity of the Ministry of Education, Yunnan Key Laboratory of Cell Metabolism and Diseases, Center for Life Science, School of Life Sciences, Yunnan University, Kunming 650021, China
- Southwest United Graduate School, Kunming650092, China
| | - Fan Lai
- State Key Laboratory for Conservation and Utilization of Bio-Resource in Yunnan, Key Laboratory for Southwest Microbial Diversity of the Ministry of Education, Yunnan Key Laboratory of Cell Metabolism and Diseases, Center for Life Science, School of Life Sciences, Yunnan University, Kunming 650021, China
- Southwest United Graduate School, Kunming650092, China
| | - Yunkun Dang
- State Key Laboratory for Conservation and Utilization of Bio-Resource in Yunnan, Key Laboratory for Southwest Microbial Diversity of the Ministry of Education, Yunnan Key Laboratory of Cell Metabolism and Diseases, Center for Life Science, School of Life Sciences, Yunnan University, Kunming 650021, China
- Southwest United Graduate School, Kunming650092, China
| |
Collapse
|
2
|
Karousis ED, Schubert K, Ban N. Coronavirus takeover of host cell translation and intracellular antiviral response: a molecular perspective. EMBO J 2024; 43:151-167. [PMID: 38200146 PMCID: PMC10897431 DOI: 10.1038/s44318-023-00019-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 11/01/2023] [Accepted: 11/24/2023] [Indexed: 01/12/2024] Open
Abstract
Coronaviruses are a group of related RNA viruses that cause respiratory diseases in humans and animals. Understanding the mechanisms of translation regulation during coronaviral infections is critical for developing antiviral therapies and preventing viral spread. Translation of the viral single-stranded RNA genome in the host cell cytoplasm is an essential step in the life cycle of coronaviruses, which affects the cellular mRNA translation landscape in many ways. Here we discuss various viral strategies of translation control, including how members of the Betacoronavirus genus shut down host cell translation and suppress host innate immune functions, as well as the role of the viral non-structural protein 1 (Nsp1) in the process. We also outline the fate of viral RNA, considering stress response mechanisms triggered in infected cells, and describe how unique viral RNA features contribute to programmed ribosomal -1 frameshifting, RNA editing, and translation shutdown evasion.
Collapse
Affiliation(s)
- Evangelos D Karousis
- Multidisciplinary Center for Infectious Diseases, University of Bern, Bern, Switzerland
- Department of Chemistry and Biochemistry, University of Bern, Bern, Switzerland
| | - Katharina Schubert
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich, Switzerland
| | - Nenad Ban
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich, Switzerland.
| |
Collapse
|
3
|
Lyu Z, Villanueva P, O’Malley L, Murphy P, Augenstreich J, Briken V, Singh A, Ling J. Genome-wide screening reveals metabolic regulation of stop-codon readthrough by cyclic AMP. Nucleic Acids Res 2023; 51:9905-9919. [PMID: 37670559 PMCID: PMC10570021 DOI: 10.1093/nar/gkad725] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 08/12/2023] [Accepted: 08/21/2023] [Indexed: 09/07/2023] Open
Abstract
Translational fidelity is critical for microbial fitness, survival and stress responses. Much remains unknown about the genetic and environmental control of translational fidelity and its single-cell heterogeneity. In this study, we used a high-throughput fluorescence-based assay to screen a knock-out library of Escherichia coli and identified over 20 genes critical for stop-codon readthrough. Most of these identified genes were not previously known to affect translational fidelity. Intriguingly, we show that several genes controlling metabolism, including cyaA and crp, enhance stop-codon readthrough. CyaA catalyzes the synthesis of cyclic adenosine monophosphate (cAMP). Combining RNA sequencing, metabolomics and biochemical analyses, we show that deleting cyaA impairs amino acid catabolism and production of ATP, thus repressing the transcription of rRNAs and tRNAs to decrease readthrough. Single-cell analyses further show that cAMP is a major driver of heterogeneity in stop-codon readthrough and rRNA expression. Our results highlight that carbon metabolism is tightly coupled with stop-codon readthrough.
Collapse
Affiliation(s)
- Zhihui Lyu
- Department of Cell Biology and Molecular Genetics, The University of Maryland, College Park, MD, USA
| | - Patricia Villanueva
- Department of Cell Biology and Molecular Genetics, The University of Maryland, College Park, MD, USA
| | - Liam O’Malley
- Department of Cell Biology and Molecular Genetics, The University of Maryland, College Park, MD, USA
| | - Parker Murphy
- Department of Cell Biology and Molecular Genetics, The University of Maryland, College Park, MD, USA
| | - Jacques Augenstreich
- Department of Cell Biology and Molecular Genetics, The University of Maryland, College Park, MD, USA
| | - Volker Briken
- Department of Cell Biology and Molecular Genetics, The University of Maryland, College Park, MD, USA
| | - Abhyudai Singh
- Department of Electrical and Computer Engineering and Biomedical Engineering, University of Delaware, Newark, DE, USA
| | - Jiqiang Ling
- Department of Cell Biology and Molecular Genetics, The University of Maryland, College Park, MD, USA
| |
Collapse
|
4
|
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.
Collapse
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;
| |
Collapse
|
5
|
Poulis P, Peske F, Rodnina MV. The many faces of ribosome translocation along the mRNA: reading frame maintenance, ribosome frameshifting and translational bypassing. Biol Chem 2023; 404:755-767. [PMID: 37077160 DOI: 10.1515/hsz-2023-0142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Accepted: 03/22/2023] [Indexed: 04/21/2023]
Abstract
In each round of translation elongation, the ribosome translocates along the mRNA by precisely one codon. Translocation is promoted by elongation factor G (EF-G) in bacteria (eEF2 in eukaryotes) and entails a number of precisely-timed large-scale structural rearrangements. As a rule, the movements of the ribosome, tRNAs, mRNA and EF-G are orchestrated to maintain the exact codon-wise step size. However, signals in the mRNA, as well as environmental cues, can change the timing and dynamics of the key rearrangements leading to recoding of the mRNA into production of trans-frame peptides from the same mRNA. In this review, we discuss recent advances on the mechanics of translocation and reading frame maintenance. Furthermore, we describe the mechanisms and biological relevance of non-canonical translocation pathways, such as hungry and programmed frameshifting and translational bypassing, and their link to disease and infection.
Collapse
Affiliation(s)
- Panagiotis Poulis
- Department of Physical Biochemistry, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, D-37077 Göttingen, Germany
| | - Frank Peske
- Department of Physical Biochemistry, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, D-37077 Göttingen, Germany
| | - Marina V Rodnina
- Department of Physical Biochemistry, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, D-37077 Göttingen, Germany
| |
Collapse
|
6
|
Choi H, Covert MW. Whole-cell modeling of E. coli confirms that in vitro tRNA aminoacylation measurements are insufficient to support cell growth and predicts a positive feedback mechanism regulating arginine biosynthesis. Nucleic Acids Res 2023; 51:5911-5930. [PMID: 37224536 PMCID: PMC10325894 DOI: 10.1093/nar/gkad435] [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: 02/02/2023] [Revised: 05/04/2023] [Accepted: 05/09/2023] [Indexed: 05/26/2023] Open
Abstract
In Escherichia coli, inconsistencies between in vitro tRNA aminoacylation measurements and in vivo protein synthesis demands were postulated almost 40 years ago, but have proven difficult to confirm. Whole-cell modeling can test whether a cell behaves in a physiologically correct manner when parameterized with in vitro measurements by providing a holistic representation of cellular processes in vivo. Here, a mechanistic model of tRNA aminoacylation, codon-based polypeptide elongation, and N-terminal methionine cleavage was incorporated into a developing whole-cell model of E. coli. Subsequent analysis confirmed the insufficiency of aminoacyl-tRNA synthetase kinetic measurements for cellular proteome maintenance, and estimated aminoacyl-tRNA synthetase kcats that were on average 7.6-fold higher. Simulating cell growth with perturbed kcats demonstrated the global impact of these in vitro measurements on cellular phenotypes. For example, an insufficient kcat for HisRS caused protein synthesis to be less robust to the natural variability in aminoacyl-tRNA synthetase expression in single cells. More surprisingly, insufficient ArgRS activity led to catastrophic impacts on arginine biosynthesis due to underexpressed N-acetylglutamate synthase, where translation depends on repeated CGG codons. Overall, the expanded E. coli model deepens understanding of how translation operates in an in vivo context.
Collapse
Affiliation(s)
- Heejo Choi
- Department of Bioengineering, Stanford University, 443 Via Ortega, Stanford, CA 94305, USA
| | - Markus W Covert
- Department of Bioengineering, Stanford University, 443 Via Ortega, Stanford, CA 94305, USA
| |
Collapse
|
7
|
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.
Collapse
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
| |
Collapse
|
8
|
Prabhakar A, Krahn N, Zhang J, Vargas-Rodriguez O, Krupkin M, Fu Z, Acosta-Reyes FJ, Ge X, Choi J, Crnković A, Ehrenberg M, Puglisi EV, Söll D, Puglisi J. Uncovering translation roadblocks during the development of a synthetic tRNA. Nucleic Acids Res 2022; 50:10201-10211. [PMID: 35882385 PMCID: PMC9561287 DOI: 10.1093/nar/gkac576] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 06/14/2022] [Accepted: 07/22/2022] [Indexed: 11/24/2022] Open
Abstract
Ribosomes are remarkable in their malleability to accept diverse aminoacyl-tRNA substrates from both the same organism and other organisms or domains of life. This is a critical feature of the ribosome that allows the use of orthogonal translation systems for genetic code expansion. Optimization of these orthogonal translation systems generally involves focusing on the compatibility of the tRNA, aminoacyl-tRNA synthetase, and a non-canonical amino acid with each other. As we expand the diversity of tRNAs used to include non-canonical structures, the question arises as to the tRNA suitability on the ribosome. Specifically, we investigated the ribosomal translation of allo-tRNAUTu1, a uniquely shaped (9/3) tRNA exploited for site-specific selenocysteine insertion, using single-molecule fluorescence. With this technique we identified ribosomal disassembly occurring from translocation of allo-tRNAUTu1 from the A to the P site. Using cryo-EM to capture the tRNA on the ribosome, we pinpointed a distinct tertiary interaction preventing fluid translocation. Through a single nucleotide mutation, we disrupted this tertiary interaction and relieved the translation roadblock. With the continued diversification of genetic code expansion, our work highlights a targeted approach to optimize translation by distinct tRNAs as they move through the ribosome.
Collapse
Affiliation(s)
| | | | | | - Oscar Vargas-Rodriguez
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06511, USA
| | - Miri Krupkin
- Department of Structural Biology, Stanford University, Stanford, CA 94305-5126, USA
| | - Ziao Fu
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Francisco J Acosta-Reyes
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Xueliang Ge
- Department of Cell and Molecular Biology, Uppsala University, Uppsala 751 24, Sweden
| | - Junhong Choi
- Department of Structural Biology, Stanford University, Stanford, CA 94305-5126, USA
| | - Ana Crnković
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06511, USA
| | - Måns Ehrenberg
- Department of Cell and Molecular Biology, Uppsala University, Uppsala 751 24, Sweden
| | | | - Dieter Söll
- Correspondence may also be addressed to Dieter Söll.
| | - Joseph Puglisi
- To whom correspondence should be addressed. Tel: +1 650 498 4397;
| |
Collapse
|
9
|
Abstract
The constrained nature of viral genomes has allowed a translational sleight of hand known as −1 Programmed Ribosomal Frameshifting (−1 PRF) to flourish. Numerous studies have sought to tease apart the mechanisms and implications of −1PRF utilizing a few techniques. The dual-luciferase assay and ribosomal profiling have driven the PRF field to make great advances; however, the use of these assays means that the full impact of the genomic and cellular context on −1 PRF is often lost. Here, we discuss how the Minimal Frameshifting Element (MFE) and its constraints can hide contextual effects on −1 PRF. We review how sequence elements proximal to the traditionally defined MFE, such as the coronavirus attenuator sequence, can affect the observed rates of −1 PRF. Further, the MFE-based approach fully obscured −1 PRF in Barley yellow dwarf virus and would render the exploration of −1 PRF difficult in Porcine reproductive and respiratory syndrome virus, Encephalomyocarditis virus, Theiler’s murine encephalomyelitis virus, and Sindbis virus. Finally, we examine how the cellular context of tRNA abundance, miRNAs, and immune response elements can affect −1 PRF. The use of MFE was instrumental in establishing the basic foundations of PRF; however, it has become clear that the contextual impact on −1 PRF is no longer the exception so much as it is the rule and argues for new approaches to study −1PRF that embrace context. We therefore urge our field to expand the strategies and methods used to explore −1 PRF.
Collapse
|
10
|
Ribosomal RNA 2'- O-methylations regulate translation by impacting ribosome dynamics. Proc Natl Acad Sci U S A 2022; 119:e2117334119. [PMID: 35294285 PMCID: PMC8944910 DOI: 10.1073/pnas.2117334119] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
SignificanceThe presence of RNA chemical modifications has long been known, but their precise molecular consequences remain unknown. 2'-O-methylation is an abundant modification that exists in RNA in all domains of life. Ribosomal RNA (rRNA) represents a functionally important RNA that is heavily modified by 2'-O-methylations. Although abundant at functionally important regions of the rRNA, the contribution of 2'-O-methylations to ribosome activities is unknown. By establishing a method to disturb rRNA 2'-O-methylation patterns, we show that rRNA 2'-O-methylations affect the function and fidelity of the ribosome and change the balance between different ribosome conformational states. Our work links 2'-O-methylation to ribosome dynamics and defines a set of critical rRNA 2'-O-methylations required for ribosome biogenesis and others that are dispensable.
Collapse
|
11
|
DeBenedictis EA, Söll D, Esvelt KM. Measuring the tolerance of the genetic code to altered codon size. eLife 2022; 11:76941. [PMID: 35293861 PMCID: PMC9094753 DOI: 10.7554/elife.76941] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 03/15/2022] [Indexed: 11/13/2022] Open
Abstract
Translation using four-base codons occurs in both natural and synthetic systems. What constraints contributed to the universal adoption of a triplet codon, rather than quadruplet codon, genetic code? Here, we investigate the tolerance of the Escherichia coli genetic code to tRNA mutations that increase codon size. We found that tRNAs from all 20 canonical isoacceptor classes can be converted to functional quadruplet tRNAs (qtRNAs). Many of these selectively incorporate a single amino acid in response to a specified four-base codon, as confirmed with mass spectrometry. However, efficient quadruplet codon translation often requires multiple tRNA mutations. Moreover, while tRNAs were largely amenable to quadruplet conversion, only nine of the twenty aminoacyl tRNA synthetases tolerate quadruplet anticodons. These may constitute a functional and mutually orthogonal set, but one that sharply limits the chemical alphabet available to a nascent all-quadruplet code. Our results suggest that the triplet codon code was selected because it is simpler and sufficient, not because a quadruplet codon code is unachievable. These data provide a blueprint for synthetic biologists to deliberately engineer an all-quadruplet expanded genetic code.
Collapse
Affiliation(s)
- Erika Alden DeBenedictis
- Department of Biological Engineering, Massachusetts Institue of Technology, Cambridge, United States
| | - Dieter Söll
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, United States
| | - Kevin M Esvelt
- Department of Media Arts and Sciences, Massachusetts Institute of Technology, Cambridge, United States
| |
Collapse
|
12
|
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.
Collapse
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
| |
Collapse
|
13
|
Bao C, Zhu M, Nykonchuk I, Wakabayashi H, Mathews DH, Ermolenko DN. Specific length and structure rather than high thermodynamic stability enable regulatory mRNA stem-loops to pause translation. Nat Commun 2022; 13:988. [PMID: 35190568 PMCID: PMC8861025 DOI: 10.1038/s41467-022-28600-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 02/03/2022] [Indexed: 11/09/2022] Open
Abstract
AbstractTranslating ribosomes unwind mRNA secondary structures by three basepairs each elongation cycle. Despite the ribosome helicase, certain mRNA stem-loops stimulate programmed ribosomal frameshift by inhibiting translation elongation. Here, using mutagenesis, biochemical and single-molecule experiments, we examine whether high stability of three basepairs, which are unwound by the translating ribosome, is critical for inducing ribosome pauses. We find that encountering frameshift-inducing mRNA stem-loops from the E. coli dnaX mRNA and the gag-pol transcript of Human Immunodeficiency Virus (HIV) hinders A-site tRNA binding and slows down ribosome translocation by 15-20 folds. By contrast, unwinding of first three basepairs adjacent to the mRNA entry channel slows down the translating ribosome by only 2-3 folds. Rather than high thermodynamic stability, specific length and structure enable regulatory mRNA stem-loops to stall translation by forming inhibitory interactions with the ribosome. Our data provide the basis for rationalizing transcriptome-wide studies of translation and searching for novel regulatory mRNA stem-loops.
Collapse
|
14
|
Abstract
Accurate protein synthesis (translation) relies on translation factors that rectify ribosome fluctuations into a unidirectional process. Understanding this process requires structural characterization of the ribosome and translation-factor dynamics. In the 2000s, crystallographic studies determined high-resolution structures of ribosomes stalled with translation factors, providing a starting point for visualizing translation. Recent progress in single-particle cryogenic electron microscopy (cryo-EM) has enabled near-atomic resolution of numerous structures sampled in heterogeneous complexes (ensembles). Ensemble and time-resolved cryo-EM have now revealed unprecedented views of ribosome transitions in the three principal stages of translation: initiation, elongation, and termination. This review focuses on how translation factors help achieve high accuracy and efficiency of translation by monitoring distinct ribosome conformations and by differentially shifting the equilibria of ribosome rearrangements for cognate and near-cognate substrates. Expected final online publication date for the Annual Review of Biochemistry, Volume 91 is June 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
Collapse
Affiliation(s)
- Andrei A Korostelev
- RNA Therapeutics Institute, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA;
| |
Collapse
|
15
|
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.
Collapse
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,
| |
Collapse
|
16
|
Insights from structural studies of the Cardiovirus 2A protein. Biosci Rep 2022; 42:230648. [PMID: 35022657 PMCID: PMC8777194 DOI: 10.1042/bsr20210406] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2021] [Revised: 01/10/2022] [Accepted: 01/10/2022] [Indexed: 11/24/2022] Open
Abstract
Cardioviruses are single-stranded RNA viruses of the family Picornaviridae. In addition to being the first example of internal ribosome entry site (IRES) utilization, cardioviruses also employ a series of alternative translation strategies, such as Stop-Go translation and programmed ribosome frameshifting. Here, we focus on cardiovirus 2A protein, which is not only a primary virulence factor, but also exerts crucial regulatory functions during translation, including activation of viral ribosome frameshifting and inhibition of host cap-dependent translation. Only recently, biochemical and structural studies have allowed us to close the gaps in our knowledge of how cardiovirus 2A is able to act in diverse translation-related processes as a novel RNA-binding protein. This review will summarize these findings, which ultimately may lead to the discovery of other RNA-mediated gene expression strategies across a broad range of RNA viruses.
Collapse
|
17
|
Iizuka R, Yamazaki H, Uemura S. Zero-mode waveguides and nanopore-based sequencing technologies accelerate single-molecule studies. Biophys Physicobiol 2022; 19:e190032. [DOI: 10.2142/biophysico.bppb-v19.0032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Accepted: 08/26/2022] [Indexed: 12/01/2022] Open
Affiliation(s)
- Ryo Iizuka
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo
| | - Hirohito Yamazaki
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo
| | - Sotaro Uemura
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo
| |
Collapse
|
18
|
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.
Collapse
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
| | | |
Collapse
|
19
|
Structural and molecular basis for Cardiovirus 2A protein as a viral gene expression switch. Nat Commun 2021; 12:7166. [PMID: 34887415 PMCID: PMC8660796 DOI: 10.1038/s41467-021-27400-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 11/12/2021] [Indexed: 12/21/2022] Open
Abstract
Programmed –1 ribosomal frameshifting (PRF) in cardioviruses is activated by the 2A protein, a multi-functional virulence factor that also inhibits cap-dependent translational initiation. Here we present the X-ray crystal structure of 2A and show that it selectively binds to a pseudoknot-like conformation of the PRF stimulatory RNA element in the viral genome. Using optical tweezers, we demonstrate that 2A stabilises this RNA element, likely explaining the increase in PRF efficiency in the presence of 2A. Next, we demonstrate a strong interaction between 2A and the small ribosomal subunit and present a cryo-EM structure of 2A bound to initiated 70S ribosomes. Multiple copies of 2A bind to the 16S rRNA where they may compete for binding with initiation and elongation factors. Together, these results define the structural basis for RNA recognition by 2A, show how 2A-mediated stabilisation of an RNA pseudoknot promotes PRF, and reveal how 2A accumulation may shut down translation during virus infection. Many RNA viruses employ programmed –1 ribosomal frameshifting (PRF) to expand their coding capacity and optimize production of viral proteins. Here, the authors report structural and biophysical analysis of protein 2A from a cardiovirus, with insights into the mechanism of its PRF-stimulatory function.
Collapse
|
20
|
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.
Collapse
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
| |
Collapse
|
21
|
Bao C, Ermolenko DN. Ribosome as a Translocase and Helicase. BIOCHEMISTRY (MOSCOW) 2021; 86:992-1002. [PMID: 34488575 PMCID: PMC8294220 DOI: 10.1134/s0006297921080095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
During protein synthesis, ribosome moves along mRNA to decode one codon after the other. Ribosome translocation is induced by a universally conserved protein, elongation factor G (EF-G) in bacteria and elongation factor 2 (EF-2) in eukaryotes. EF-G-induced translocation results in unwinding of the intramolecular secondary structures of mRNA by three base pairs at a time that renders the translating ribosome a processive helicase. Professor Alexander Sergeevich Spirin has made numerous seminal contributions to understanding the molecular mechanism of translocation. Here, we review Spirin's insights into the ribosomal translocation and recent advances in the field that stemmed from Spirin's pioneering work. We also discuss key remaining challenges in studies of translocase and helicase activities of the ribosome.
Collapse
Affiliation(s)
- Chen Bao
- Department of Biochemistry & Biophysics, School of Medicine and Dentistry and Center for RNA Biology, University of Rochester, Rochester, NY, USA.
| | - Dmitri N Ermolenko
- Department of Biochemistry & Biophysics, School of Medicine and Dentistry and Center for RNA Biology, University of Rochester, Rochester, NY, USA.
| |
Collapse
|
22
|
Štambuk N, Konjevoda P, Pavan J. Antisense Peptide Technology for Diagnostic Tests and Bioengineering Research. Int J Mol Sci 2021; 22:9106. [PMID: 34502016 PMCID: PMC8431130 DOI: 10.3390/ijms22179106] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2021] [Revised: 08/10/2021] [Accepted: 08/13/2021] [Indexed: 01/01/2023] Open
Abstract
Antisense peptide technology (APT) is based on a useful heuristic algorithm for rational peptide design. It was deduced from empirical observations that peptides consisting of complementary (sense and antisense) amino acids interact with higher probability and affinity than the randomly selected ones. This phenomenon is closely related to the structure of the standard genetic code table, and at the same time, is unrelated to the direction of its codon sequence translation. The concept of complementary peptide interaction is discussed, and its possible applications to diagnostic tests and bioengineering research are summarized. Problems and difficulties that may arise using APT are discussed, and possible solutions are proposed. The methodology was tested on the example of SARS-CoV-2. It is shown that the CABS-dock server accurately predicts the binding of antisense peptides to the SARS-CoV-2 receptor binding domain without requiring predefinition of the binding site. It is concluded that the benefits of APT outweigh the costs of random peptide screening and could lead to considerable savings in time and resources, especially if combined with other computational and immunochemical methods.
Collapse
Affiliation(s)
- Nikola Štambuk
- Center for Nuclear Magnetic Resonance, Ruđer Bošković Institute, Bijenička cesta 54, HR-10000 Zagreb, Croatia
| | - Paško Konjevoda
- Laboratory for Epigenomics, Division of Molecular Medicine, Ruđer Bošković Institute, Bijenička cesta 54, HR-10000 Zagreb, Croatia
| | - Josip Pavan
- Department of Ophthalmology, University Hospital Dubrava, Avenija Gojka Šuška 6, HR-10000 Zagreb, Croatia
| |
Collapse
|
23
|
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.
Collapse
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.)
| |
Collapse
|
24
|
Chang KC, Wen JD. Programmed -1 ribosomal frameshifting from the perspective of the conformational dynamics of mRNA and ribosomes. Comput Struct Biotechnol J 2021; 19:3580-3588. [PMID: 34257837 PMCID: PMC8246090 DOI: 10.1016/j.csbj.2021.06.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 06/11/2021] [Accepted: 06/12/2021] [Indexed: 11/01/2022] Open
Abstract
Programmed -1 ribosomal frameshifting (-1 PRF) is a translation mechanism that regulates the relative expression level of two proteins encoded on the same messenger RNA (mRNA). This regulation is commonly used by viruses such as coronaviruses and retroviruses but rarely by host human cells, and for this reason, it has long been considered as a therapeutic target for antiviral drug development. Understanding the molecular mechanism of -1 PRF is one step toward this goal. Minus-one PRF occurs with a certain efficiency when translating ribosomes encounter the specialized mRNA signal consisting of the frameshifting site and a downstream stimulatory structure, which impedes translocation of the ribosome. The impeded ribosome can still undergo profound conformational changes to proceed with translocation; however, some of these changes may be unique and essential to frameshifting. In addition, most stimulatory structures exhibit conformational dynamics and sufficient mechanical strength, which, when under the action of ribosomes, may in turn further promote -1 PRF efficiency. In this review, we discuss how the dynamic features of ribosomes and mRNA stimulatory structures may influence the occurrence of -1 PRF and propose a hypothetical frameshifting model that recapitulates the role of conformational dynamics.
Collapse
Affiliation(s)
- Kai-Chun Chang
- Department of Bioengineering and Therapeutic Sciences, Schools of Medicine and Pharmacy, University of California, San Francisco, CA 94158, United States
| | - 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
| |
Collapse
|
25
|
De Lise F, Strazzulli A, Iacono R, Curci N, Di Fenza M, Maurelli L, Moracci M, Cobucci-Ponzano B. Programmed Deviations of Ribosomes From Standard Decoding in Archaea. Front Microbiol 2021; 12:688061. [PMID: 34149676 PMCID: PMC8211752 DOI: 10.3389/fmicb.2021.688061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 05/04/2021] [Indexed: 11/13/2022] Open
Abstract
Genetic code decoding, initially considered to be universal and immutable, is now known to be flexible. In fact, in specific genes, ribosomes deviate from the standard translational rules in a programmed way, a phenomenon globally termed recoding. Translational recoding, which has been found in all domains of life, includes a group of events occurring during gene translation, namely stop codon readthrough, programmed ± 1 frameshifting, and ribosome bypassing. These events regulate protein expression at translational level and their mechanisms are well known and characterized in viruses, bacteria and eukaryotes. In this review we summarize the current state-of-the-art of recoding in the third domain of life. In Archaea, it was demonstrated and extensively studied that translational recoding regulates the decoding of the 21st and the 22nd amino acids selenocysteine and pyrrolysine, respectively, and only one case of programmed -1 frameshifting has been reported so far in Saccharolobus solfataricus P2. However, further putative events of translational recoding have been hypothesized in other archaeal species, but not extensively studied and confirmed yet. Although this phenomenon could have some implication for the physiology and adaptation of life in extreme environments, this field is still underexplored and genes whose expression could be regulated by recoding are still poorly characterized. The study of these recoding episodes in Archaea is urgently needed.
Collapse
Affiliation(s)
- Federica De Lise
- Institute of Biosciences and BioResources - National Research Council of Italy, Naples, Italy
| | - Andrea Strazzulli
- Department of Biology, University of Naples Federico II, Complesso Universitario di Monte S. Angelo, Naples, Italy.,Task Force on Microbiome Studies, University of Naples Federico II, Naples, Italy
| | - Roberta Iacono
- Institute of Biosciences and BioResources - National Research Council of Italy, Naples, Italy.,Department of Biology, University of Naples Federico II, Complesso Universitario di Monte S. Angelo, Naples, Italy
| | - Nicola Curci
- Institute of Biosciences and BioResources - National Research Council of Italy, Naples, Italy.,Department of Biology, University of Naples Federico II, Complesso Universitario di Monte S. Angelo, Naples, Italy
| | - Mauro Di Fenza
- Institute of Biosciences and BioResources - National Research Council of Italy, Naples, Italy
| | - Luisa Maurelli
- Institute of Biosciences and BioResources - National Research Council of Italy, Naples, Italy
| | - Marco Moracci
- Institute of Biosciences and BioResources - National Research Council of Italy, Naples, Italy.,Department of Biology, University of Naples Federico II, Complesso Universitario di Monte S. Angelo, Naples, Italy.,Task Force on Microbiome Studies, University of Naples Federico II, Naples, Italy
| | | |
Collapse
|
26
|
Bhatt PR, Scaiola A, Loughran G, Leibundgut M, Kratzel A, Meurs R, Dreos R, O'Connor KM, McMillan A, Bode JW, Thiel V, Gatfield D, Atkins JF, Ban N. Structural basis of ribosomal frameshifting during translation of the SARS-CoV-2 RNA genome. Science 2021; 372:1306-1313. [PMID: 34029205 PMCID: PMC8168617 DOI: 10.1126/science.abf3546] [Citation(s) in RCA: 150] [Impact Index Per Article: 50.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 02/24/2021] [Accepted: 05/07/2021] [Indexed: 12/22/2022]
Abstract
Programmed ribosomal frameshifting is a key event during translation of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA genome that allows synthesis of the viral RNA-dependent RNA polymerase and downstream proteins. Here, we present the cryo-electron microscopy structure of a translating mammalian ribosome primed for frameshifting on the viral RNA. The viral RNA adopts a pseudoknot structure that lodges at the entry to the ribosomal messenger RNA (mRNA) channel to generate tension in the mRNA and promote frameshifting, whereas the nascent viral polyprotein forms distinct interactions with the ribosomal tunnel. Biochemical experiments validate the structural observations and reveal mechanistic and regulatory features that influence frameshifting efficiency. Finally, we compare compounds previously shown to reduce frameshifting with respect to their ability to inhibit SARS-CoV-2 replication, establishing coronavirus frameshifting as a target for antiviral intervention.
Collapse
Affiliation(s)
- Pramod R Bhatt
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich, Switzerland.,School of Biochemistry and Cell Biology, University College Cork, Cork T12 XF62, Ireland.,School of Microbiology, University College Cork, Cork T12 K8AF, Ireland
| | - Alain Scaiola
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich, Switzerland
| | - Gary Loughran
- School of Biochemistry and Cell Biology, University College Cork, Cork T12 XF62, Ireland
| | - Marc Leibundgut
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich, Switzerland
| | - Annika Kratzel
- Institute of Virology and Immunology, University of Bern, Bern, Switzerland.,Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, University of Bern, Bern, Switzerland.,Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Romane Meurs
- Center for Integrative Genomics, Génopode, University of Lausanne, 1015 Lausanne, Switzerland
| | - René Dreos
- Center for Integrative Genomics, Génopode, University of Lausanne, 1015 Lausanne, Switzerland
| | - Kate M O'Connor
- School of Biochemistry and Cell Biology, University College Cork, Cork T12 XF62, Ireland
| | - Angus McMillan
- Laboratorium für Organische Chemie, Department of Chemistry and Applied Biosciences, ETH Zurich, Zurich, Switzerland
| | - Jeffrey W Bode
- Laboratorium für Organische Chemie, Department of Chemistry and Applied Biosciences, ETH Zurich, Zurich, Switzerland
| | - Volker Thiel
- Institute of Virology and Immunology, University of Bern, Bern, Switzerland.,Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - David Gatfield
- Center for Integrative Genomics, Génopode, University of Lausanne, 1015 Lausanne, Switzerland
| | - John F Atkins
- School of Biochemistry and Cell Biology, University College Cork, Cork T12 XF62, Ireland. .,School of Microbiology, University College Cork, Cork T12 K8AF, Ireland.,MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Nenad Ban
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich, Switzerland.
| |
Collapse
|
27
|
Mao Y, Lin R, Xu S, Wang Y. High-Resolution DNA Dual-Rulers Reveal a New Intermediate State in Ribosomal Frameshifting. Chembiochem 2021; 22:1775-1778. [PMID: 33458897 PMCID: PMC8014572 DOI: 10.1002/cbic.202000863] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 01/13/2021] [Indexed: 01/06/2023]
Abstract
Ribosomal frameshifting is an important pathway used by many viruses for protein synthesis that involves mRNA translocation of various numbers of nucleotides. Resolving the mRNA positions with subnucleotide precision will provide critical mechanistic information that is difficult to obtain with current techniques. We report a method of high‐resolution DNA rulers with subnucleotide precision and the discovery of new frameshifting intermediate states on mRNA containing a GA7G motif. Two intermediate states were observed with the aid of fusidic acid, one at the “0” reading frame and the other near the “−1” reading frame, in contrast to the “−2” and “−1” frameshifting products found in the absence of the antibiotic. We termed the new near‐“−1” intermediate the Post(−1*) state because it was shifted by approximately half a nucleotide compared to the normal “−1” reading frame at the 5’‐end. This indicates a ribosome conformation that is different from the conventional model of three reading frames. Our work reveals uniquely precise mRNA motions and subtle conformational changes that will complement structural and fluorescence studies.
Collapse
Affiliation(s)
- Yujia Mao
- Department of Chemistry, University of Houston, 3585 Cullen Blvd, Houston, TX 77204, USA
| | - Ran Lin
- Department of Biology and Biochemistry, University of Houston, Houston, TX 77204, USA
| | - Shoujun Xu
- Department of Chemistry, University of Houston, 3585 Cullen Blvd, Houston, TX 77204, USA
| | - Yuhong Wang
- Department of Biology and Biochemistry, University of Houston, Houston, TX 77204, USA
| |
Collapse
|
28
|
Halma MTJ, Ritchie DB, Woodside MT. Conformational Shannon Entropy of mRNA Structures from Force Spectroscopy Measurements Predicts the Efficiency of -1 Programmed Ribosomal Frameshift Stimulation. PHYSICAL REVIEW LETTERS 2021; 126:038102. [PMID: 33543960 DOI: 10.1103/physrevlett.126.038102] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2020] [Accepted: 12/15/2020] [Indexed: 06/12/2023]
Abstract
-1 programmed ribosomal frameshifting (-1 PRF) is stimulated by structures in messenger RNA (mRNA), but the factors determining -1 PRF efficiency are unclear. We show that -1 PRF efficiency varies directly with the conformational heterogeneity of the stimulatory structure, quantified as the Shannon entropy of the state occupancy, for a panel of stimulatory structures with efficiencies from 2% to 80%. The correlation is force dependent and vanishes at forces above those applied by the ribosome. These results support the hypothesis that heterogeneous conformational dynamics are a key factor in stimulating -1 PRF.
Collapse
Affiliation(s)
- Matthew T J Halma
- Department of Physics, University of Alberta, Edmonton, Alberta T6G 2E1, Canada
| | - Dustin B Ritchie
- Department of Physics, University of Alberta, Edmonton, Alberta T6G 2E1, Canada
| | - Michael T Woodside
- Department of Physics, University of Alberta, Edmonton, Alberta T6G 2E1, Canada
| |
Collapse
|
29
|
Niblett D, Nelson C, Leung CS, Rexroad G, Cozy J, Zhou J, Lancaster L, Noller HF. Mutations in domain IV of elongation factor EF-G confer -1 frameshifting. RNA (NEW YORK, N.Y.) 2021; 27:40-53. [PMID: 33008838 PMCID: PMC7749637 DOI: 10.1261/rna.077339.120] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 09/24/2020] [Indexed: 05/25/2023]
Abstract
A recent crystal structure of a ribosome complex undergoing partial translocation in the absence of elongation factor EF-G showed disruption of codon-anticodon pairing and slippage of the reading frame by -1, directly implicating EF-G in preservation of the translational reading frame. Among mutations identified in a random screen for dominant-lethal mutations of EF-G were a cluster of six that map to the tip of domain IV, which has been shown to contact the codon-anticodon duplex in trapped translocation intermediates. In vitro synthesis of a full-length protein using these mutant EF-Gs revealed dramatically increased -1 frameshifting, providing new evidence for a role for domain IV of EF-G in maintaining the reading frame. These mutations also caused decreased rates of mRNA translocation and rotational movement of the head and body domains of the 30S ribosomal subunit during translocation. Our results are in general agreement with recent findings from Rodnina and coworkers based on in vitro translation of an oligopeptide using EF-Gs containing mutations at two positions in domain IV, who found an inverse correlation between the degree of frameshifting and rates of translocation. Four of our six mutations are substitutions at positions that interact with the translocating tRNA, in each case contacting the RNA backbone of the anticodon loop. We suggest that EF-G helps to preserve the translational reading frame by preventing uncoupled movement of the tRNA through these contacts; a further possibility is that these interactions may stabilize a conformation of the anticodon that favors base-pairing with its codon.
Collapse
Affiliation(s)
- Dustin Niblett
- Center for Molecular Biology of RNA and Department of Molecular, Cell and Developmental Biology, University of California at Santa Cruz, Santa Cruz, California 95064, USA
| | - Charlotte Nelson
- Center for Molecular Biology of RNA and Department of Molecular, Cell and Developmental Biology, University of California at Santa Cruz, Santa Cruz, California 95064, USA
| | - Calvin S Leung
- Center for Molecular Biology of RNA and Department of Molecular, Cell and Developmental Biology, University of California at Santa Cruz, Santa Cruz, California 95064, USA
| | - Gillian Rexroad
- Center for Molecular Biology of RNA and Department of Molecular, Cell and Developmental Biology, University of California at Santa Cruz, Santa Cruz, California 95064, USA
| | - Jake Cozy
- Center for Molecular Biology of RNA and Department of Molecular, Cell and Developmental Biology, University of California at Santa Cruz, Santa Cruz, California 95064, USA
| | - Jie Zhou
- Center for Molecular Biology of RNA and Department of Molecular, Cell and Developmental Biology, University of California at Santa Cruz, Santa Cruz, California 95064, USA
| | - Laura Lancaster
- Center for Molecular Biology of RNA and Department of Molecular, Cell and Developmental Biology, University of California at Santa Cruz, Santa Cruz, California 95064, USA
| | - Harry F Noller
- Center for Molecular Biology of RNA and Department of Molecular, Cell and Developmental Biology, University of California at Santa Cruz, Santa Cruz, California 95064, USA
| |
Collapse
|
30
|
Ribosome Pausing at Inefficient Codons at the End of the Replicase Coding Region Is Important for Hepatitis C Virus Genome Replication. Int J Mol Sci 2020; 21:ijms21186955. [PMID: 32971876 PMCID: PMC7555993 DOI: 10.3390/ijms21186955] [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: 07/22/2020] [Revised: 08/26/2020] [Accepted: 09/15/2020] [Indexed: 12/17/2022] Open
Abstract
Hepatitis C virus (HCV) infects liver cells and often causes chronic infection, also leading to liver cirrhosis and cancer. In the cytoplasm, the viral structural and non-structural (NS) proteins are directly translated from the plus strand HCV RNA genome. The viral proteins NS3 to NS5B proteins constitute the replication complex that is required for RNA genome replication via a minus strand antigenome. The most C-terminal protein in the genome is the NS5B replicase, which needs to initiate antigenome RNA synthesis at the very 3′-end of the plus strand. Using ribosome profiling of cells replicating full-length infectious HCV genomes, we uncovered that ribosomes accumulate at the HCV stop codon and about 30 nucleotides upstream of it. This pausing is due to the presence of conserved rare, inefficient Wobble codons upstream of the termination site. Synonymous substitution of these inefficient codons to efficient codons has negative consequences for viral RNA replication but not for viral protein synthesis. This pausing may allow the enzymatically active replicase core to find its genuine RNA template in cis, while the protein is still held in place by being stuck with its C-terminus in the exit tunnel of the paused ribosome.
Collapse
|
31
|
Wakabayashi H, Warnasooriya C, Ermolenko DN. Extending the Spacing between the Shine-Dalgarno Sequence and P-Site Codon Reduces the Rate of mRNA Translocation. J Mol Biol 2020; 432:4612-4622. [PMID: 32544497 DOI: 10.1016/j.jmb.2020.06.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 06/08/2020] [Accepted: 06/09/2020] [Indexed: 12/24/2022]
Abstract
By forming base-pairing interactions with the 3' end of 16S rRNA, mRNA Shine-Dalgarno (SD) sequences positioned upstream of open reading frames facilitate translation initiation. During the elongation phase of protein synthesis, intragenic SD-like sequences stimulate ribosome frameshifting and may also slow down ribosome movement along mRNA. Here, we show that the length of the spacer between the SD sequence and P-site codon strongly affects the rate of ribosome translocation. Increasing the spacer length beyond 6 nt destabilizes mRNA-tRNA-ribosome interactions and results in a 5- to 10-fold reduction of the translocation rate. These observations suggest that during translation, the spacer between the SD sequence and P-site codon undergoes structural rearrangements, which slow down mRNA translocation and promote mRNA frameshifting.
Collapse
Affiliation(s)
- Hironao Wakabayashi
- Department of Biochemistry & Biophysics at School of Medicine and Dentistry and Center for RNA Biology, University of Rochester, Rochester, NY 14642, USA
| | - Chandani Warnasooriya
- Department of Biochemistry & Biophysics at School of Medicine and Dentistry and Center for RNA Biology, University of Rochester, Rochester, NY 14642, USA
| | - Dmitri N Ermolenko
- Department of Biochemistry & Biophysics at School of Medicine and Dentistry and Center for RNA Biology, University of Rochester, Rochester, NY 14642, USA.
| |
Collapse
|
32
|
Zhang K, Zheludev IN, Hagey RJ, Wu MTP, Haslecker R, Hou YJ, Kretsch R, Pintilie GD, Rangan R, Kladwang W, Li S, Pham EA, Bernardin-Souibgui C, Baric RS, Sheahan TP, D Souza V, Glenn JS, Chiu W, Das R. Cryo-electron Microscopy and Exploratory Antisense Targeting of the 28-kDa Frameshift Stimulation Element from the SARS-CoV-2 RNA Genome. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2020. [PMID: 32743589 DOI: 10.1101/2020.07.18.209270] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Drug discovery campaigns against Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) are beginning to target the viral RNA genome 1, 2 . The frameshift stimulation element (FSE) of the SARS-CoV-2 genome is required for balanced expression of essential viral proteins and is highly conserved, making it a potential candidate for antiviral targeting by small molecules and oligonucleotides 3-6 . To aid global efforts focusing on SARS-CoV-2 frameshifting, we report exploratory results from frameshifting and cellular replication experiments with locked nucleic acid (LNA) antisense oligonucleotides (ASOs), which support the FSE as a therapeutic target but highlight difficulties in achieving strong inactivation. To understand current limitations, we applied cryogenic electron microscopy (cryo-EM) and the Ribosolve 7 pipeline to determine a three-dimensional structure of the SARS-CoV-2 FSE, validated through an RNA nanostructure tagging method. This is the smallest macromolecule (88 nt; 28 kDa) resolved by single-particle cryo-EM at subnanometer resolution to date. The tertiary structure model, defined to an estimated accuracy of 5.9 Å, presents a topologically complex fold in which the 5' end threads through a ring formed inside a three-stem pseudoknot. Our results suggest an updated model for SARS-CoV-2 frameshifting as well as binding sites that may be targeted by next generation ASOs and small molecules.
Collapse
|
33
|
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.
Collapse
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
| | | | | |
Collapse
|
34
|
Mikl M, Pilpel Y, Segal E. High-throughput interrogation of programmed ribosomal frameshifting in human cells. Nat Commun 2020; 11:3061. [PMID: 32546731 PMCID: PMC7297798 DOI: 10.1038/s41467-020-16961-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 05/28/2020] [Indexed: 12/30/2022] Open
Abstract
Programmed ribosomal frameshifting (PRF) is the controlled slippage of the translating ribosome to an alternative frame. This process is widely employed by human viruses such as HIV and SARS coronavirus and is critical for their replication. Here, we developed a high-throughput approach to assess the frameshifting potential of a sequence. We designed and tested >12,000 sequences based on 15 viral and human PRF events, allowing us to systematically dissect the rules governing ribosomal frameshifting and discover novel regulatory inputs based on amino acid properties and tRNA availability. We assessed the natural variation in HIV gag-pol frameshifting rates by testing >500 clinical isolates and identified subtype-specific differences and associations between viral load in patients and the optimality of PRF rates. We devised computational models that accurately predict frameshifting potential and frameshifting rates, including subtle differences between HIV isolates. This approach can contribute to the development of antiviral agents targeting PRF.
Collapse
Affiliation(s)
- Martin Mikl
- Department of Computer Science and Applied Mathematics, Rehovot, 7610001, Israel.
- Department of Molecular Cell Biology and Weizmann Institute of Science, Rehovot, 7610001, Israel.
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, 7610001, Israel.
- Department of Human Biology, Faculty of Natural Sciences, University of Haifa, Mount Carmel, Haifa, 31905, Israel.
| | - Yitzhak Pilpel
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Eran Segal
- Department of Computer Science and Applied Mathematics, Rehovot, 7610001, Israel.
- Department of Molecular Cell Biology and Weizmann Institute of Science, Rehovot, 7610001, Israel.
| |
Collapse
|
35
|
Bao C, Loerch S, Ling C, Korostelev AA, Grigorieff N, Ermolenko DN. mRNA stem-loops can pause the ribosome by hindering A-site tRNA binding. eLife 2020; 9:e55799. [PMID: 32427100 PMCID: PMC7282821 DOI: 10.7554/elife.55799] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Accepted: 05/18/2020] [Indexed: 12/27/2022] Open
Abstract
Although the elongating ribosome is an efficient helicase, certain mRNA stem-loop structures are known to impede ribosome movement along mRNA and stimulate programmed ribosome frameshifting via mechanisms that are not well understood. Using biochemical and single-molecule Förster resonance energy transfer (smFRET) experiments, we studied how frameshift-inducing stem-loops from E. coli dnaX mRNA and the gag-pol transcript of Human Immunodeficiency Virus (HIV) perturb translation elongation. We find that upon encountering the ribosome, the stem-loops strongly inhibit A-site tRNA binding and ribosome intersubunit rotation that accompanies translation elongation. Electron cryo-microscopy (cryo-EM) reveals that the HIV stem-loop docks into the A site of the ribosome. Our results suggest that mRNA stem-loops can transiently escape the ribosome helicase by binding to the A site. Thus, the stem-loops can modulate gene expression by sterically hindering tRNA binding and inhibiting translation elongation.
Collapse
Affiliation(s)
- Chen Bao
- Department of Biochemistry and Biophysics at School of Medicine and Dentistry and Center for RNA Biology, University of RochesterRochesterUnited States
| | - Sarah Loerch
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
| | - Clarence Ling
- Department of Biochemistry and Biophysics at School of Medicine and Dentistry and Center for RNA Biology, University of RochesterRochesterUnited States
| | - Andrei A Korostelev
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical SchoolWorcesterUnited States
- RNA Therapeutics Institute, University of Massachusetts Medical SchoolWorcesterUnited States
| | - Nikolaus Grigorieff
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
- RNA Therapeutics Institute, University of Massachusetts Medical SchoolWorcesterUnited States
| | - Dmitri N Ermolenko
- Department of Biochemistry and Biophysics at School of Medicine and Dentistry and Center for RNA Biology, University of RochesterRochesterUnited States
| |
Collapse
|
36
|
Harrington HR, Zimmer MH, Chamness LM, Nash V, Penn WD, Miller TF, Mukhopadhyay S, Schlebach JP. Cotranslational folding stimulates programmed ribosomal frameshifting in the alphavirus structural polyprotein. J Biol Chem 2020; 295:6798-6808. [PMID: 32169904 DOI: 10.1074/jbc.ra120.012706] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 03/04/2020] [Indexed: 11/06/2022] Open
Abstract
Viruses maximize their genetic coding capacity through a variety of biochemical mechanisms, including programmed ribosomal frameshifting (PRF), which facilitates the production of multiple proteins from a single mRNA transcript. PRF is typically stimulated by structural elements within the mRNA that generate mechanical tension between the transcript and ribosome. However, in this work, we show that the forces generated by the cotranslational folding of the nascent polypeptide chain can also enhance PRF. Using an array of biochemical, cellular, and computational techniques, we first demonstrate that the Sindbis virus structural polyprotein forms two competing topological isomers during its biosynthesis at the ribosome-translocon complex. We then show that the formation of one of these topological isomers is linked to PRF. Coarse-grained molecular dynamics simulations reveal that the translocon-mediated membrane integration of a transmembrane domain upstream from the ribosomal slip site generates a force on the nascent polypeptide chain that scales with observed frameshifting. Together, our results indicate that cotranslational folding of this viral protein generates a tension that stimulates PRF. To our knowledge, this constitutes the first example in which the conformational state of the nascent polypeptide chain has been linked to PRF. These findings raise the possibility that, in addition to RNA-mediated translational recoding, a variety of cotranslational folding or binding events may also stimulate PRF.
Collapse
Affiliation(s)
| | - Matthew H Zimmer
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125
| | - Laura M Chamness
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405
| | - Veronica Nash
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405
| | - Wesley D Penn
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405
| | - Thomas F Miller
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125
| | | | | |
Collapse
|