1
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Banna HA, Das NK, Ojha M, Koirala D. Advances in chaperone-assisted RNA crystallography using synthetic antibodies. BBA ADVANCES 2023; 4:100101. [PMID: 37655005 PMCID: PMC10466895 DOI: 10.1016/j.bbadva.2023.100101] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 07/13/2023] [Accepted: 08/17/2023] [Indexed: 09/02/2023] Open
Abstract
RNA molecules play essential roles in many biological functions, from gene expression regulation, cellular growth, and metabolism to catalysis. They frequently fold into three-dimensional structures to perform their functions. Therefore, determining RNA structure represents a key step for understanding the structure-function relationships and developing RNA-targeted therapeutics. X-ray crystallography remains a method of choice for determining high-resolution RNA structures, but it has been challenging due to difficulties associated with RNA crystallization and phasing. Several natural and synthetic RNA binding proteins have been used to facilitate RNA crystallography. Having unique properties to help crystal packing and phasing, synthetic antibody fragments, specifically the Fabs, have emerged as promising RNA crystallization chaperones, and so far, over a dozen of RNA structures have been solved using this strategy. Nevertheless, multiple steps in this approach need to be improved, including the recombinant expression of these anti-RNA Fabs, to warrant the full potential of these synthetic Fabs as RNA crystallization chaperones. This review highlights the nuts and bolts and recent advances in the chaperone-assisted RNA crystallography approach, specifically emphasizing the Fab antibody fragments as RNA crystallization chaperones.
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Affiliation(s)
- Hasan Al Banna
- Department of Chemistry and Biochemistry, University of Maryland Baltimore County, Baltimore, MD 21250, USA
| | - Naba Krishna Das
- Department of Chemistry and Biochemistry, University of Maryland Baltimore County, Baltimore, MD 21250, USA
| | - Manju Ojha
- Department of Chemistry and Biochemistry, University of Maryland Baltimore County, Baltimore, MD 21250, USA
| | - Deepak Koirala
- Department of Chemistry and Biochemistry, University of Maryland Baltimore County, Baltimore, MD 21250, USA
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2
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Hlaing ST, Srimanote P, Tongtawe P, Khantisitthiporn O, Glab-Ampai K, Chulanetra M, Thanongsaksrikul J. Isolation and Characterization of scFv Antibody against Internal Ribosomal Entry Site of Enterovirus A71. Int J Mol Sci 2023; 24:9865. [PMID: 37373012 DOI: 10.3390/ijms24129865] [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: 04/07/2023] [Revised: 06/02/2023] [Accepted: 06/06/2023] [Indexed: 06/29/2023] Open
Abstract
Enterovirus A71 (EV-A71) is one of the causative agents of hand-foot-mouth disease, which can be associated with neurocomplications of the central nervous system. A limited understanding of the virus's biology and pathogenesis has led to the unavailability of effective anti-viral treatments. The EV-A71 RNA genome carries type I internal ribosomal entry site (IRES) at 5' UTR that plays an essential role in the viral genomic translation. However, the detailed mechanism of IRES-mediated translation has not been elucidated. In this study, sequence analysis revealed that the domains IV, V, and VI of EV-A71 IRES contained the structurally conserved regions. The selected region was transcribed in vitro and labeled with biotin to use as an antigen for selecting the single-chain variable fragment (scFv) antibody from the naïve phage display library. The so-obtained scFv, namely, scFv #16-3, binds specifically to EV-A71 IRES. The molecular docking showed that the interaction between scFv #16-3 and EV-A71 IRES was mediated by the preferences of amino acid residues, including serine, tyrosine, glycine, lysine, and arginine on the antigen-binding sites contacted the nucleotides on the IRES domains IV and V. The so-produced scFv has the potential to develop as a structural biology tool to study the biology of the EV-A71 RNA genome.
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Affiliation(s)
- Su Thandar Hlaing
- Graduate Program in Biomedical Sciences, Faculty of Allied Health Sciences, Thammasat University, Pathumtani 12120, Thailand
| | - Potjanee Srimanote
- Graduate Program in Biomedical Sciences, Faculty of Allied Health Sciences, Thammasat University, Pathumtani 12120, Thailand
- Thammasat University Research Unit in Molecular Pathogenesis and Immunology of Infectious Diseases, Thammasat University, Pathumthani 12120, Thailand
| | - Pongsri Tongtawe
- Graduate Program in Biomedical Sciences, Faculty of Allied Health Sciences, Thammasat University, Pathumtani 12120, Thailand
| | - Onruedee Khantisitthiporn
- Thammasat University Research Unit in Molecular Pathogenesis and Immunology of Infectious Diseases, Thammasat University, Pathumthani 12120, Thailand
- Department of Medical Technology, Faculty of Allied Health Sciences, Thammasat University, Pathumthani 12120, Thailand
| | - Kittirat Glab-Ampai
- Center of Research Excellence in Therapeutic Proteins and Antibody Engineering, Department of Parasitology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Monrat Chulanetra
- Center of Research Excellence in Therapeutic Proteins and Antibody Engineering, Department of Parasitology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Jeeraphong Thanongsaksrikul
- Graduate Program in Biomedical Sciences, Faculty of Allied Health Sciences, Thammasat University, Pathumtani 12120, Thailand
- Thammasat University Research Unit in Molecular Pathogenesis and Immunology of Infectious Diseases, Thammasat University, Pathumthani 12120, Thailand
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3
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Cleary NG, Bryant PW, Lamson DM, Newman AP, St George K. A custom hepatitis A virus assay for whole-genome sequencing. J Virol Methods 2023; 312:114649. [PMID: 36375537 DOI: 10.1016/j.jviromet.2022.114649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 11/03/2022] [Accepted: 11/07/2022] [Indexed: 11/13/2022]
Abstract
Since 2016, the United States has experienced a resurgence in the number of hepatitis A virus (HAV) cases and outbreaks. These outbreaks have been sustained by person-to-person transmission with cases occurring predominantly in high-risk populations including intravenous drug users, individuals experiencing homelessness, and men who have sex with men. To investigate HAV transmission, a molecular-surveillance system consisting of real-time RT-PCR (rRT-PCR) for detection, and a conventional RT-PCR assay for genotyping of HAV, was established in New York State (NYS) in 2019. Since then, a total of 271 HAV-positive serum samples collected from cases across NYS between 2019 and 2021 were identified by rRT-PCR. To rapidly and efficiently generate HAV whole-genome sequences, a custom AmpliSeq™ panel was designed in collaboration with Thermo Fisher. To streamline the process, sample preparation was performed on an Ion Chef and sequencing on an Ion S5XL. Of the 271 HAV-positive samples, the whole-genome sequencing (WGS) assay successfully generated 134 near-complete, high-quality HAV sequences. Phylogenetic analysis of the VP1-2A region identified 216 IB, 48 IA, and 2 IIIA genotypes, while 5 were unable to be typed due to poor sequence in this key region. The HAV whole-genome sequencing approach provided a more efficient and streamlined approach for genotyping HAV compared to previous methods and resulted in phylogenetic trees with enhanced resolution compared to the HAV VP1-2A region alone.
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Affiliation(s)
- Nora G Cleary
- Laboratory of Viral Diseases, Wadsworth Center, New York State Department of Health, Albany, New York 12208, USA
| | - Patrick W Bryant
- Laboratory of Viral Diseases, Wadsworth Center, New York State Department of Health, Albany, New York 12208, USA.
| | - Daryl M Lamson
- Laboratory of Viral Diseases, Wadsworth Center, New York State Department of Health, Albany, New York 12208, USA
| | - Alexandra P Newman
- Bureau of Communicable Disease Control, New York State Department of Health, Albany, New York 12237, USA
| | - Kirsten St George
- Laboratory of Viral Diseases, Wadsworth Center, New York State Department of Health, Albany, New York 12208, USA; Department of Biomedical Science, University at Albany, SUNY, Albany, New York 12144, USA
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4
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Zhong V, Archibald BN, Brophy JAN. Transcriptional and post-transcriptional controls for tuning gene expression in plants. CURRENT OPINION IN PLANT BIOLOGY 2023; 71:102315. [PMID: 36462457 DOI: 10.1016/j.pbi.2022.102315] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 10/22/2022] [Accepted: 10/27/2022] [Indexed: 06/17/2023]
Abstract
Plant biotechnologists seek to modify plants through genetic reprogramming, but our ability to precisely control gene expression in plants is still limited. Here, we review transcription and translation in the model plants Arabidopsis thaliana and Nicotiana benthamiana with an eye toward control points that may be used to predictably modify gene expression. We highlight differences in gene expression requirements between these plants and other species, and discuss the ways in which our understanding of gene expression has been used to engineer plants. This review is intended to serve as a resource for plant scientists looking to achieve precise control over gene expression.
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Affiliation(s)
- Vivian Zhong
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Bella N Archibald
- Department of Bioengineering, Stanford University, Stanford, CA, USA
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5
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Saon MS, Kirkpatrick CC, Znosko BM. Identification and characterization of RNA pentaloop sequence families. NAR Genom Bioinform 2023; 5:lqac102. [PMID: 36632613 PMCID: PMC9830547 DOI: 10.1093/nargab/lqac102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 10/28/2022] [Accepted: 12/12/2022] [Indexed: 01/11/2023] Open
Abstract
One of the current methods for predicting RNA tertiary structure is fragment-based homology, which predicts tertiary structure from secondary structure. For a successful prediction, this method requires a library of the tertiary structures of small motifs clipped from previously solved RNA 3D structures. Because of the limited number of available tertiary structures, it is not practical to find structures for all sequences of all motifs. Identifying sequence families for motifs can fill the gaps because all sequences within a family are expected to have similar structural features. Currently, a collection of well-characterized sequence families has been identified for tetraloops. Because of their prevalence and biological functions, pentaloop structures should also be well-characterized. In this study, 10 pentaloop sequence families are identified. For each family, the common and distinguishing structural features are highlighted. These sequence families can be used to predict the tertiary structure of pentaloop sequences for which a solved structure is not available.
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Affiliation(s)
- Md Sharear Saon
- Department of Chemistry, Saint Louis University, Saint Louis, MO 63103, USA
| | | | - Brent M Znosko
- To whom correspondence should be addressed. Tel: +1 314 977 8567; Fax: +1 314 977 2521;
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6
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Abstract
Despite excellent vaccines, resurgent outbreaks of hepatitis A have caused thousands of hospitalizations and hundreds of deaths within the United States in recent years. There is no effective antiviral therapy for hepatitis A, and many aspects of the hepatitis A virus (HAV) replication cycle remain to be elucidated. Replication requires the zinc finger protein ZCCHC14 and noncanonical TENT4 poly(A) polymerases with which it associates, but the underlying mechanism is unknown. Here, we show that ZCCHC14 and TENT4A/B are required for viral RNA synthesis following translation of the viral genome in infected cells. Cross-linking immunoprecipitation sequencing (CLIP-seq) experiments revealed that ZCCHC14 binds a small stem-loop in the HAV 5' untranslated RNA possessing a Smaug recognition-like pentaloop to which it recruits TENT4. TENT4 polymerases lengthen and stabilize the 3' poly(A) tails of some cellular and viral mRNAs, but the chemical inhibition of TENT4A/B with the dihydroquinolizinone RG7834 had no impact on the length of the HAV 3' poly(A) tail, stability of HAV RNA, or cap-independent translation of the viral genome. By contrast, RG7834 inhibited the incorporation of 5-ethynyl uridine into nascent HAV RNA, indicating that TENT4A/B function in viral RNA synthesis. Consistent with potent in vitro antiviral activity against HAV (IC50 6.11 nM), orally administered RG7834 completely blocked HAV infection in Ifnar1-/- mice, and sharply reduced serum alanine aminotransferase activities, hepatocyte apoptosis, and intrahepatic inflammatory cell infiltrates in mice with acute hepatitis A. These results reveal requirements for ZCCHC14-TENT4A/B in hepatovirus RNA synthesis, and suggest that TENT4A/B inhibitors may be useful for preventing or treating hepatitis A in humans.
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7
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Krochmal D, Shao Y, Li NS, DasGupta S, Shelke SA, Koirala D, Piccirilli JA. Structural basis for substrate binding and catalysis by a self-alkylating ribozyme. Nat Chem Biol 2022; 18:376-384. [PMID: 35058645 DOI: 10.1038/s41589-021-00950-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Accepted: 11/23/2021] [Indexed: 12/26/2022]
Abstract
Ribozymes that react with small-molecule probes have important applications in transcriptomics and chemical biology, such as RNA labeling and imaging. Understanding the structural basis for these RNA-modifying reactions will enable the development of better tools for studying RNA. Nevertheless, high-resolution structures and underlying catalytic mechanisms for members of this ribozyme class remain elusive. Here, we focus on a self-alkylating ribozyme that catalyzes nitrogen-carbon bond formation between a specific guanine and a 2,3-disubstituted epoxide substrate and report the crystal structures of a self-alkylating ribozyme, including both alkylated and apo forms, at 1.71-Å and 2.49-Å resolution, respectively. The ribozyme assumes an elongated hairpin-like architecture preorganized to accommodate the epoxide substrate in a hook-shaped conformation. Observed reactivity of substrate analogs together with an inverse, log-linear pH dependence of the reaction rate suggests a requirement for epoxide protonation, possibly assisted by the ether oxygens within the substrate.
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Affiliation(s)
- Daniel Krochmal
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, USA
| | - Yaming Shao
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, USA
| | - Nan-Sheng Li
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, USA
| | - Saurja DasGupta
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, USA
| | - Sandip A Shelke
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, USA
| | - Deepak Koirala
- Department of Chemistry and Biochemistry, University of Maryland Baltimore County, Baltimore, MD, USA.
| | - Joseph A Piccirilli
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, USA.
- Department of Chemistry, The University of Chicago, Chicago, IL, USA.
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8
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Bou-Nader C, Bothra A, Garboczi DN, Leppla SH, Zhang J. Structural basis of R-loop recognition by the S9.6 monoclonal antibody. Nat Commun 2022; 13:1641. [PMID: 35347133 PMCID: PMC8960830 DOI: 10.1038/s41467-022-29187-7] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Accepted: 03/02/2022] [Indexed: 12/31/2022] Open
Abstract
R-loops are ubiquitous, dynamic nucleic-acid structures that play fundamental roles in DNA replication and repair, chromatin and transcription regulation, as well as telomere maintenance. The DNA-RNA hybrid–specific S9.6 monoclonal antibody is widely used to map R-loops. Here, we report crystal structures of a S9.6 antigen-binding fragment (Fab) free and bound to a 13-bp hybrid duplex. We demonstrate that S9.6 exhibits robust selectivity in binding hybrids over double-stranded (ds) RNA and in categorically rejecting dsDNA. S9.6 asymmetrically recognizes a compact epitope of two consecutive RNA nucleotides via their 2′-hydroxyl groups and six consecutive DNA nucleotides via their backbone phosphate and deoxyribose groups. Recognition is mediated principally by aromatic and basic residues of the S9.6 heavy chain, which closely track the curvature of the hybrid minor groove. These findings reveal the molecular basis for S9.6 recognition of R-loops, detail its binding specificity, identify a new hybrid-recognition strategy, and provide a framework for S9.6 protein engineering. The S9.6 monoclonal antibody is widely used to map R-loops genome wide. Here, Bou-Nader et al., define the nucleic acid-binding specificity of S9.6 and report its crystal structures free and bound to a hybrid, which reveal the asymmetric recognition of the RNA and DNA strands and its A-form conformation.
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Affiliation(s)
- Charles Bou-Nader
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, 20892, USA
| | - Ankur Bothra
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, MD, 20892, USA
| | - David N Garboczi
- Structural Biology Section, Research Technologies Branch, National Institute of Allergy and Infectious Diseases, Bethesda, MD, 20892, USA
| | - Stephen H Leppla
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, MD, 20892, USA.
| | - Jinwei Zhang
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, 20892, USA.
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9
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Francisco-Velilla R, Embarc-Buh A, Abellan S, Martinez-Salas E. Picornavirus translation strategies. FEBS Open Bio 2022; 12:1125-1141. [PMID: 35313388 PMCID: PMC9157412 DOI: 10.1002/2211-5463.13400] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 02/02/2022] [Accepted: 03/18/2022] [Indexed: 12/15/2022] Open
Abstract
The genome of viruses classified as picornaviruses consists of a single monocistronic positive strand RNA. The coding capacity of these RNA viruses is rather limited, and thus, they rely on the cellular machinery for their viral replication cycle. Upon the entry of the virus into susceptible cells, the viral RNA initially competes with cellular mRNAs for access to the protein synthesis machinery. Not surprisingly, picornaviruses have evolved specialized strategies that successfully allow the expression of viral gene products, which we outline in this review. The main feature of all picornavirus genomes is the presence of a heavily structured RNA element on the 5´UTR, referred to as an internal ribosome entry site (IRES) element, which directs viral protein synthesis as well and, consequently, triggers the subsequent steps required for viral replication. Here, we will summarize recent studies showing that picornavirus IRES elements consist of a modular structure, providing sites of interaction for ribosome subunits, eIFs, and a selective group of RNA‐binding proteins.
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Affiliation(s)
| | - Azman Embarc-Buh
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Madrid, Spain
| | - Salvador Abellan
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Madrid, Spain
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10
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Sorokin II, Vassilenko KS, Terenin IM, Kalinina NO, Agol VI, Dmitriev SE. Non-Canonical Translation Initiation Mechanisms Employed by Eukaryotic Viral mRNAs. BIOCHEMISTRY. BIOKHIMIIA 2021; 86:1060-1094. [PMID: 34565312 PMCID: PMC8436584 DOI: 10.1134/s0006297921090042] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 08/04/2021] [Accepted: 08/04/2021] [Indexed: 12/12/2022]
Abstract
Viruses exploit the translation machinery of an infected cell to synthesize their proteins. Therefore, viral mRNAs have to compete for ribosomes and translation factors with cellular mRNAs. To succeed, eukaryotic viruses adopt multiple strategies. One is to circumvent the need for m7G-cap through alternative instruments for ribosome recruitment. These include internal ribosome entry sites (IRESs), which make translation independent of the free 5' end, or cap-independent translational enhancers (CITEs), which promote initiation at the uncapped 5' end, even if located in 3' untranslated regions (3' UTRs). Even if a virus uses the canonical cap-dependent ribosome recruitment, it can still perturb conventional ribosomal scanning and start codon selection. The pressure for genome compression often gives rise to internal and overlapping open reading frames. Their translation is initiated through specific mechanisms, such as leaky scanning, 43S sliding, shunting, or coupled termination-reinitiation. Deviations from the canonical initiation reduce the dependence of viral mRNAs on translation initiation factors, thereby providing resistance to antiviral mechanisms and cellular stress responses. Moreover, viruses can gain advantage in a competition for the translational machinery by inactivating individual translational factors and/or replacing them with viral counterparts. Certain viruses even create specialized intracellular "translation factories", which spatially isolate the sites of their protein synthesis from cellular antiviral systems, and increase availability of translational components. However, these virus-specific mechanisms may become the Achilles' heel of a viral life cycle. Thus, better understanding of the unconventional mechanisms of viral mRNA translation initiation provides valuable insight for developing new approaches to antiviral therapy.
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Affiliation(s)
- Ivan I Sorokin
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234, Russia
- Institute of Protein Research, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region, 141701, Russia
| | - Konstantin S Vassilenko
- Institute of Protein Research, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia
| | - Ilya M Terenin
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234, Russia
| | - Natalia O Kalinina
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234, Russia
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia
| | - Vadim I Agol
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234, Russia
- Institute of Poliomyelitis, Chumakov Center for Research and Development of Immunobiological Products, Russian Academy of Sciences, Moscow, 108819, Russia
| | - Sergey E Dmitriev
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234, Russia.
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, 119991, Russia
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, 119234, Russia
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Siblings or doppelgängers? Deciphering the evolution of structured cis-regulatory RNAs beyond homology. Biochem Soc Trans 2021; 48:1941-1951. [PMID: 32869842 PMCID: PMC7609027 DOI: 10.1042/bst20191060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 08/04/2020] [Accepted: 08/06/2020] [Indexed: 11/21/2022]
Abstract
Structured cis-regulatory RNAs have evolved across all domains of life, highlighting the utility and plasticity of RNA as a regulatory molecule. Homologous RNA sequences and structures often have similar functions, but homology may also be deceiving. The challenges that derive from trying to assign function to structure and vice versa are not trivial. Bacterial riboswitches, viral and eukaryotic IRESes, CITEs, and 3′ UTR elements employ an array of mechanisms to exert their effects. Bioinformatic searches coupled with biochemical and functional validation have elucidated some shared and many unique ways cis-regulators are employed in mRNA transcripts. As cis-regulatory RNAs are resolved in greater detail, it is increasingly apparent that shared homology can mask the full spectrum of mRNA cis-regulator functional diversity. Furthermore, similar functions may be obscured by lack of obvious sequence similarity. Thus looking beyond homology is crucial for furthering our understanding of RNA-based regulation.
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12
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Kanda T, Sasaki R, Masuzaki R, Moriyama M. Artificial intelligence and machine learning could support drug development for hepatitis A virus internal ribosomal entry sites. Artif Intell Gastroenterol 2021; 2:1-9. [DOI: 10.35712/aig.v2.i1.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 12/29/2020] [Accepted: 02/12/2021] [Indexed: 02/06/2023] Open
Abstract
Hepatitis A virus (HAV) infection is still an important health issue worldwide. Although several effective HAV vaccines are available, it is difficult to perform universal vaccination in certain countries. Therefore, it may be better to develop antivirals against HAV for the prevention of severe hepatitis A. We found that several drugs potentially inhibit HAV internal ribosomal entry site-dependent translation and HAV replication. Artificial intelligence and machine learning could also support screening of anti-HAV drugs, using drug repositioning and drug rescue approaches.
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Affiliation(s)
- Tatsuo Kanda
- Division of Gastroenterology and Hepatology, Department of Medicine, Nihon University School of Medicine, Itabashi-ku 173-8610, Tokyo, Japan
| | - Reina Sasaki
- Division of Gastroenterology and Hepatology, Department of Medicine, Nihon University School of Medicine, Itabashi-ku 173-8610, Tokyo, Japan
| | - Ryota Masuzaki
- Division of Gastroenterology and Hepatology, Department of Medicine, Nihon University School of Medicine, Itabashi-ku 173-8610, Tokyo, Japan
| | - Mitsuhiko Moriyama
- Division of Gastroenterology and Hepatology, Department of Medicine, Nihon University School of Medicine, Itabashi-ku 173-8610, Tokyo, Japan
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13
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Arhab Y, Bulakhov AG, Pestova TV, Hellen CU. Dissemination of Internal Ribosomal Entry Sites (IRES) Between Viruses by Horizontal Gene Transfer. Viruses 2020; 12:v12060612. [PMID: 32512856 PMCID: PMC7354566 DOI: 10.3390/v12060612] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 06/01/2020] [Accepted: 06/02/2020] [Indexed: 12/19/2022] Open
Abstract
Members of Picornaviridae and of the Hepacivirus, Pegivirus and Pestivirus genera of Flaviviridae all contain an internal ribosomal entry site (IRES) in the 5'-untranslated region (5'UTR) of their genomes. Each class of IRES has a conserved structure and promotes 5'-end-independent initiation of translation by a different mechanism. Picornavirus 5'UTRs, including the IRES, evolve independently of other parts of the genome and can move between genomes, most commonly by intratypic recombination. We review accumulating evidence that IRESs are genetic entities that can also move between members of different genera and even between families. Type IV IRESs, first identified in the Hepacivirus genus, have subsequently been identified in over 25 genera of Picornaviridae, juxtaposed against diverse coding sequences. In several genera, members have either type IV IRES or an IRES of type I, II or III. Similarly, in the genus Pegivirus, members contain either a type IV IRES or an unrelated type; both classes of IRES also occur in members of the genus Hepacivirus. IRESs utilize different mechanisms, have different factor requirements and contain determinants of viral growth, pathogenesis and cell type specificity. Their dissemination between viruses by horizontal gene transfer has unexpectedly emerged as an important facet of viral evolution.
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14
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Koirala D, Lewicka A, Koldobskaya Y, Huang H, Piccirilli JA. Synthetic Antibody Binding to a Preorganized RNA Domain of Hepatitis C Virus Internal Ribosome Entry Site Inhibits Translation. ACS Chem Biol 2020; 15:205-216. [PMID: 31765566 DOI: 10.1021/acschembio.9b00785] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Structured RNA elements within the internal ribosome entry site (IRES) of hepatitis C virus (HCV) genome hijack host cell machinery for translation initiation through a cap-independent mechanism. Here, using a phage display selection, we obtained two antibody fragments (Fabs), HCV2 and HCV3, against HCV IRES that bind the RNA with dissociation constants of 32 ± 7 nM and 37 ± 8 nM respectively, specifically recognizing the so-called junction IIIabc (JIIIabc). We used these Fabs as crystallization chaperones and determined the high-resolution crystal structures of JIIIabc-HCV2 and -HCV3 complexes at 1.81 Å and 2.75 Å resolution respectively, revealing an antiparallel four-way junction with the IIIa and IIIc subdomains brought together through tertiary interactions. The RNA conformation observed in the structures supports the structural model for this region derived from cryo-EM data for the HCV IRES-40S ribosome complex, suggesting that the tertiary fold of the RNA preorganizes the domain for interactions with the 40S ribosome. Strikingly, both Fabs and the ribosomal protein eS27 not only interact with a common subset of nucleotides within the JIIIabc but also use physiochemically similar sets of protein residues to do so, suggesting that the RNA surface is well-suited for interactions with proteins, perhaps analogous to the "hot spot" concept elaborated for protein-protein interactions. Using a rabbit reticulocyte lysate-based translation assay with a bicistronic reporter construct, we further demonstrated that Fabs HCV2 and HCV3 specifically inhibit the HCV IRES-directed translation, implicating disruption of the JIIIabc-ribosome interaction as a potential therapeutic strategy against HCV.
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Affiliation(s)
- Deepak Koirala
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, Illinois 60637, United States
| | - Anna Lewicka
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, Illinois 60637, United States
| | - Yelena Koldobskaya
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, Illinois 60637, United States
| | - Hao Huang
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, Illinois 60637, United States
| | - Joseph A. Piccirilli
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, Illinois 60637, United States
- Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, United States
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