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Fuentes Y, Olguín V, López-Ulloa B, Mendonça D, Ramos H, Abdalla A, Guajardo-Contreras G, Niu M, Rojas-Araya B, Mouland A, López-Lastra M. Heterogeneous nuclear ribonucleoprotein K promotes cap-independent translation initiation of retroviral mRNAs. Nucleic Acids Res 2024; 52:2625-2647. [PMID: 38165048 PMCID: PMC10954487 DOI: 10.1093/nar/gkad1221] [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: 04/25/2023] [Revised: 12/07/2023] [Accepted: 12/15/2023] [Indexed: 01/03/2024] Open
Abstract
Translation initiation of the human immunodeficiency virus-type 1 (HIV-1) genomic mRNA (vRNA) is cap-dependent or mediated by an internal ribosome entry site (IRES). The HIV-1 IRES requires IRES-transacting factors (ITAFs) for function. In this study, we evaluated the role of the heterogeneous nuclear ribonucleoprotein K (hnRNPK) as a potential ITAF for the HIV-1 IRES. In HIV-1-expressing cells, the depletion of hnRNPK reduced HIV-1 vRNA translation. Furthermore, both the depletion and overexpression of hnRNPK modulated HIV-1 IRES activity. Phosphorylations and protein arginine methyltransferase 1 (PRMT1)-induced asymmetrical dimethylation (aDMA) of hnRNPK strongly impacted the protein's ability to promote the activity of the HIV-1 IRES. We also show that hnRNPK acts as an ITAF for the human T cell lymphotropic virus-type 1 (HTLV-1) IRES, present in the 5'UTR of the viral sense mRNA, but not for the IRES present in the antisense spliced transcript encoding the HTLV-1 basic leucine zipper protein (sHBZ). This study provides evidence for a novel role of the host hnRNPK as an ITAF that stimulates IRES-mediated translation initiation for the retroviruses HIV-1 and HTLV-1.
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Affiliation(s)
- Yazmín Fuentes
- Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Departamento de Enfermedades Infecciosas e Inmunología Pediátrica, Escuela de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile
| | - Valeria Olguín
- Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Departamento de Enfermedades Infecciosas e Inmunología Pediátrica, Escuela de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile
| | - Brenda López-Ulloa
- Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Departamento de Enfermedades Infecciosas e Inmunología Pediátrica, Escuela de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile
| | - Dafne Mendonça
- Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Departamento de Enfermedades Infecciosas e Inmunología Pediátrica, Escuela de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile
| | - Hade Ramos
- Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Departamento de Enfermedades Infecciosas e Inmunología Pediátrica, Escuela de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile
| | - Ana Luiza Abdalla
- HIV-1 RNA Trafficking Laboratory, Lady Davis Institute at the Jewish General Hospital, Montréal, Quebec H3T 1E2, Canada
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec H4A 3J1, Canada
| | - Gabriel Guajardo-Contreras
- HIV-1 RNA Trafficking Laboratory, Lady Davis Institute at the Jewish General Hospital, Montréal, Quebec H3T 1E2, Canada
- Department of Medicine, McGill University, Montreal, Quebec H4A 3J1, Canada
| | - Meijuan Niu
- HIV-1 RNA Trafficking Laboratory, Lady Davis Institute at the Jewish General Hospital, Montréal, Quebec H3T 1E2, Canada
| | - Barbara Rojas-Araya
- Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Departamento de Enfermedades Infecciosas e Inmunología Pediátrica, Escuela de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile
| | - Andrew J Mouland
- HIV-1 RNA Trafficking Laboratory, Lady Davis Institute at the Jewish General Hospital, Montréal, Quebec H3T 1E2, Canada
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec H4A 3J1, Canada
- Department of Medicine, McGill University, Montreal, Quebec H4A 3J1, Canada
| | - Marcelo López-Lastra
- Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Departamento de Enfermedades Infecciosas e Inmunología Pediátrica, Escuela de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile
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Fernández-García L, Ahumada-Marchant C, Lobos-Ávila P, Brauer B, Bustos FJ, Arriagada G. The Mytilus chilensis Steamer-like Element-1 Retrotransposon Antisense mRNA Harbors an Internal Ribosome Entry Site That Is Modulated by hnRNPK. Viruses 2024; 16:403. [PMID: 38543768 PMCID: PMC10974842 DOI: 10.3390/v16030403] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Revised: 02/29/2024] [Accepted: 03/03/2024] [Indexed: 05/23/2024] Open
Abstract
LTR-retrotransposons are transposable elements characterized by the presence of long terminal repeats (LTRs) directly flanking an internal coding region. They share genome organization and replication strategies with retroviruses. Steamer-like Element-1 (MchSLE-1) is an LTR-retrotransposon identified in the genome of the Chilean blue mussel Mytilus chilensis. MchSLE-1 is transcribed; however, whether its RNA is also translated and the mechanism underlying such translation remain to be elucidated. Here, we characterize the MchSLE-1 translation mechanism. We found that the MchSLE-1 5' and 3'LTRs command transcription of sense and antisense RNAs, respectively. Using luciferase reporters commanded by the untranslated regions (UTRs) of MchSLE-1, we found that in vitro 5'UTR sense is unable to initiate translation, whereas the antisense 5'UTR initiates translation even when the eIF4E-eIF4G interaction was disrupted, suggesting the presence of an internal ribosomal entry site (IRES). The antisense 5'UTR IRES activity was tested using bicistronic reporters. The antisense 5'UTR has IRES activity only when the mRNA is transcribed in the nucleus, suggesting that nuclear RNA-binding proteins are required to modulate its activity. Indeed, heterogeneous nuclear ribonucleoprotein K (hnRNPK) was identified as an IRES trans-acting factor (ITAF) of the MchSLE-1 IRES. To our knowledge, this is the first report describing an IRES in an antisense mRNA derived from a mussel LTR-retrotransposon.
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Affiliation(s)
| | | | | | | | | | - Gloria Arriagada
- Instituto de Ciencias Biomedicas, Facultad de Medicina y Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago 83700071, Chile; (L.F.-G.); (C.A.-M.); (P.L.-Á.); (B.B.); (F.J.B.)
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3
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Clarke JP, Thibault PA, Fatima S, Salapa HE, Kalyaanamoorthy S, Ganesan A, Levin MC. Sequence- and structure-specific RNA oligonucleotide binding attenuates heterogeneous nuclear ribonucleoprotein A1 dysfunction. Front Mol Biosci 2023; 10:1178439. [PMID: 37426420 PMCID: PMC10325567 DOI: 10.3389/fmolb.2023.1178439] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Accepted: 06/01/2023] [Indexed: 07/11/2023] Open
Abstract
The RNA binding protein heterogeneous nuclear ribonucleoprotein A1 (A1) regulates RNA metabolism, which is crucial to maintaining cellular homeostasis. A1 dysfunction mechanistically contributes to reduced cell viability and loss, but molecular mechanisms of how A1 dysfunction affects cell viability and loss, and methodologies to attenuate its dysfunction, are lacking. Utilizing in silico molecular modeling and an in vitro optogenetic system, this study examined the consequences of RNA oligonucleotide (RNAO) treatment on attenuating A1 dysfunction and its downstream cellular effects. In silico and thermal shift experiments revealed that binding of RNAOs to the RNA Recognition Motif 1 of A1 is stabilized by sequence- and structure-specific RNAO-A1 interactions. Using optogenetics to model A1 cellular dysfunction, we show that sequence- and structure-specific RNAOs significantly attenuated abnormal cytoplasmic A1 self-association kinetics and A1 cytoplasmic clustering. Downstream of A1 dysfunction, we demonstrate that A1 clustering affects the formation of stress granules, activates cell stress, and inhibits protein translation. With RNAO treatment, we show that stress granule formation is attenuated, cell stress is inhibited, and protein translation is restored. This study provides evidence that sequence- and structure-specific RNAO treatment attenuates A1 dysfunction and its downstream effects, thus allowing for the development of A1-specific therapies that attenuate A1 dysfunction and restore cellular homeostasis.
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Affiliation(s)
- Joseph P. Clarke
- Department of Health Sciences, College of Medicine, University of Saskatchewan, Saskatoon, SK, Canada
- Office of the Saskatchewan Multiple Sclerosis Clinical Research Chair, University of Saskatchewan, Saskatoon, SK, Canada
| | - Patricia A. Thibault
- Office of the Saskatchewan Multiple Sclerosis Clinical Research Chair, University of Saskatchewan, Saskatoon, SK, Canada
- Department of Medicine, Neurology Division, University of Saskatchewan, Saskatoon, SK, Canada
| | - Sakina Fatima
- ArGan’s Lab, School of Pharmacy, Faculty of Science, University of Waterloo, Waterloo, ON, Canada
| | - Hannah E. Salapa
- Office of the Saskatchewan Multiple Sclerosis Clinical Research Chair, University of Saskatchewan, Saskatoon, SK, Canada
- Department of Medicine, Neurology Division, University of Saskatchewan, Saskatoon, SK, Canada
| | - Subha Kalyaanamoorthy
- Department of Chemistry, Faculty of Science, University of Waterloo, Waterloo, ON, Canada
| | - Aravindhan Ganesan
- ArGan’s Lab, School of Pharmacy, Faculty of Science, University of Waterloo, Waterloo, ON, Canada
| | - Michael C. Levin
- Department of Health Sciences, College of Medicine, University of Saskatchewan, Saskatoon, SK, Canada
- Office of the Saskatchewan Multiple Sclerosis Clinical Research Chair, University of Saskatchewan, Saskatoon, SK, Canada
- Department of Medicine, Neurology Division, University of Saskatchewan, Saskatoon, SK, Canada
- Department of Anatomy, Physiology and Pharmacology, University of Saskatchewan, Saskatoon, SK, Canada
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Cellular Targets of HIV-1 Protease: Just the Tip of the Iceberg? Viruses 2023; 15:v15030712. [PMID: 36992421 PMCID: PMC10053624 DOI: 10.3390/v15030712] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 03/05/2023] [Accepted: 03/07/2023] [Indexed: 03/12/2023] Open
Abstract
Human immunodeficiency virus 1 (HIV-1) viral protease (PR) is one of the most studied viral enzymes and a crucial antiviral target. Despite its well-characterized role in virion maturation, an increasing body of research is starting to focus on its ability to cleave host cell proteins. Such findings are apparently in contrast with the dogma of HIV-1 PR activity being restricted to the interior of nascent virions and suggest catalytic activity within the host cell environment. Given the limited amount of PR present in the virion at the time of infection, such events mainly occur during late viral gene expression, mediated by newly synthesized Gag-Pol polyprotein precursors, rather than before proviral integration. HIV-1 PR mainly targets proteins involved in three different processes: those involved in translation, those controlling cell survival, and restriction factors responsible for innate/intrinsic antiviral responses. Indeed, by cleaving host cell translation initiation factors, HIV-1 PR can impair cap-dependent translation, thus promoting IRES-mediated translation of late viral transcripts and viral production. By targeting several apoptotic factors, it modulates cell survival, thus promoting immune evasion and viral dissemination. Additionally, HIV-1 PR counteracts restriction factors incorporated in the virion that would otherwise interfere with nascent virus vitality. Thus, HIV-1 PR appears to modulate host cell function at different times and locations during its life cycle, thereby ensuring efficient viral persistency and propagation. However, we are far from having a complete picture of PR-mediated host cell modulation, which is emerging as a field that needs further investigation.
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Upstream of N-Ras (Unr/CSDE1) Interacts with NCp7 and Gag, Modulating HIV-1 IRES-Mediated Translation Initiation. Viruses 2022; 14:v14081798. [PMID: 36016420 PMCID: PMC9413769 DOI: 10.3390/v14081798] [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: 07/21/2022] [Revised: 08/11/2022] [Accepted: 08/15/2022] [Indexed: 11/25/2022] Open
Abstract
The Human Immunodeficiency Virus-1 (HIV-1) nucleocapsid protein (NC) as a mature protein or as a domain of the Gag precursor plays important roles in the early and late phases of the infection. To better understand its roles, we searched for new cellular partners and identified the RNA-binding protein Unr/CSDE1, Upstream of N-ras, whose interaction with Gag and NCp7 was confirmed by co-immunoprecipitation and FRET-FLIM. Unr interaction with Gag was found to be RNA-dependent and mediated by its NC domain. Using a dual luciferase assay, Unr was shown to act as an ITAF (IRES trans-acting factor), increasing the HIV-1 IRES-dependent translation. Point mutations of the HIV-1 IRES in a consensus Unr binding motif were found to alter both the IRES activity and its activation by Unr, suggesting a strong dependence of the IRES on Unr. Interestingly, Unr stimulatory effect is counteracted by NCp7, while Gag increases the Unr-promoted IRES activity, suggesting a differential Unr effect on the early and late phases of viral infection. Finally, knockdown of Unr in HeLa cells leads to a decrease in infection by a non-replicative lentivector, proving its functional implication in the early phase of viral infection.
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Slobodin B, Sehrawat U, Lev A, Hayat D, Zuckerman B, Fraticelli D, Ogran A, Ben-Shmuel A, Bar-David E, Levy H, Ulitsky I, Dikstein R. Cap-independent translation and a precisely located RNA sequence enable SARS-CoV-2 to control host translation and escape anti-viral response. Nucleic Acids Res 2022; 50:8080-8092. [PMID: 35849342 PMCID: PMC9371909 DOI: 10.1093/nar/gkac615] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 06/09/2022] [Accepted: 07/04/2022] [Indexed: 12/29/2022] Open
Abstract
Translation of SARS-CoV-2-encoded mRNAs by the host ribosomes is essential for its propagation. Following infection, the early expressed viral protein NSP1 binds the ribosome, represses translation, and induces mRNA degradation, while the host elicits an anti-viral response. The mechanisms enabling viral mRNAs to escape this multifaceted repression remain obscure. Here we show that expression of NSP1 leads to destabilization of multi-exon cellular mRNAs, while intron-less transcripts, such as viral mRNAs and anti-viral interferon genes, remain relatively stable. We identified a conserved and precisely located cap-proximal RNA element devoid of guanosines that confers resistance to NSP1-mediated translation inhibition. Importantly, the primary sequence rather than the secondary structure is critical for protection. We further show that the genomic 5'UTR of SARS-CoV-2 drives cap-independent translation and promotes expression of NSP1 in an eIF4E-independent and Torin1-resistant manner. Upon expression, NSP1 further enhances cap-independent translation. However, the sub-genomic 5'UTRs are highly sensitive to eIF4E availability, rendering viral propagation partially sensitive to Torin1. We conclude that the combined NSP1-mediated degradation of spliced mRNAs and translation inhibition of single-exon genes, along with the unique features present in the viral 5'UTRs, ensure robust expression of viral mRNAs. These features can be exploited as potential therapeutic targets.
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Affiliation(s)
- Boris Slobodin
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Urmila Sehrawat
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot 76100, Israel.,Department of Cancer Biology and Genetics, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Anastasia Lev
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Daniel Hayat
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Binyamin Zuckerman
- Department of Biological Regulation, The Weizmann Institute of Science, Rehovot 76100, Israel.,Gladstone/UCSF Center for Cell Circuitry, Gladstone Institutes, San Francisco, CA 94158, USA
| | - Davide Fraticelli
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Ariel Ogran
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Amir Ben-Shmuel
- Department of Infectious Diseases, Israel Institute for Biological Research, Ness-Ziona 7410001 Israel
| | - Elad Bar-David
- Department of Infectious Diseases, Israel Institute for Biological Research, Ness-Ziona 7410001 Israel
| | - Haim Levy
- Department of Infectious Diseases, Israel Institute for Biological Research, Ness-Ziona 7410001 Israel
| | - Igor Ulitsky
- Department of Biological Regulation, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Rivka Dikstein
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot 76100, Israel
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RNA-Binding Proteins as Regulators of Internal Initiation of Viral mRNA Translation. Viruses 2022; 14:v14020188. [PMID: 35215780 PMCID: PMC8879377 DOI: 10.3390/v14020188] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 01/03/2022] [Accepted: 01/14/2022] [Indexed: 12/17/2022] Open
Abstract
Viruses are obligate intracellular parasites that depend on the host’s protein synthesis machinery for translating their mRNAs. The viral mRNA (vRNA) competes with the host mRNA to recruit the translational machinery, including ribosomes, tRNAs, and the limited eukaryotic translation initiation factor (eIFs) pool. Many viruses utilize non-canonical strategies such as targeting host eIFs and RNA elements known as internal ribosome entry sites (IRESs) to reprogram cellular gene expression, ensuring preferential translation of vRNAs. In this review, we discuss vRNA IRES-mediated translation initiation, highlighting the role of RNA-binding proteins (RBPs), other than the canonical translation initiation factors, in regulating their activity.
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8
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Ramos H, Monette A, Niu M, Barrera A, López-Ulloa B, Fuentes Y, Guizar P, Pino K, DesGroseillers L, Mouland A, López-Lastra M. The double-stranded RNA-binding protein, Staufen1, is an IRES-transacting factor regulating HIV-1 cap-independent translation initiation. Nucleic Acids Res 2022; 50:411-429. [PMID: 34893869 PMCID: PMC8754648 DOI: 10.1093/nar/gkab1188] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 11/06/2021] [Accepted: 11/16/2021] [Indexed: 02/05/2023] Open
Abstract
Translation initiation of the viral genomic mRNA (vRNA) of human immunodeficiency virus-type 1 (HIV-1) can be mediated by a cap- or an internal ribosome entry site (IRES)-dependent mechanism. A previous report shows that Staufen1, a cellular double-stranded (ds) RNA-binding protein (RBP), binds to the 5'untranslated region (5'UTR) of the HIV-1 vRNA and promotes its cap-dependent translation. In this study, we now evaluate the role of Staufen1 as an HIV-1 IRES-transacting factor (ITAF). We first confirm that Staufen1 associates with both the HIV-1 vRNA and the Gag protein during HIV-1 replication. We found that in HIV-1-expressing cells, siRNA-mediated depletion of Staufen1 reduces HIV-1 vRNA translation. Using dual-luciferase bicistronic mRNAs, we show that the siRNA-mediated depletion and cDNA-mediated overexpression of Staufen1 acutely regulates HIV-1 IRES activity. Furthermore, we show that Staufen1-vRNA interaction is required for the enhancement of HIV-1 IRES activity. Interestingly, we find that only Staufen1 harboring an intact dsRNA-binding domain 3 (dsRBD3) rescues HIV-1 IRES activity in Staufen1 CRISPR-Cas9 gene edited cells. Finally, we show that the expression of Staufen1-dsRBD3 alone enhances HIV-1 IRES activity. This study provides evidence of a novel role for Staufen1 as an ITAF promoting HIV-1 vRNA IRES activity.
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Affiliation(s)
- Hade Ramos
- Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Departamento de Enfermedades Infecciosas e Inmunología Pediátrica, Escuela de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile
| | - Anne Monette
- HIV-1 RNA Trafficking Laboratory, Lady Davis Institute at the Jewish General Hospital, Montréal, Québec H3T 1E2, Canada
| | - Meijuan Niu
- HIV-1 RNA Trafficking Laboratory, Lady Davis Institute at the Jewish General Hospital, Montréal, Québec H3T 1E2, Canada
| | - Aldo Barrera
- Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Departamento de Enfermedades Infecciosas e Inmunología Pediátrica, Escuela de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile
| | - Brenda López-Ulloa
- Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Departamento de Enfermedades Infecciosas e Inmunología Pediátrica, Escuela de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile
| | - Yazmín Fuentes
- Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Departamento de Enfermedades Infecciosas e Inmunología Pediátrica, Escuela de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile
| | - Paola Guizar
- HIV-1 RNA Trafficking Laboratory, Lady Davis Institute at the Jewish General Hospital, Montréal, Québec H3T 1E2, Canada
- Department of Medicine, McGill University, Montréal, Québec H4A 3J1, Canada
| | - Karla Pino
- Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Departamento de Enfermedades Infecciosas e Inmunología Pediátrica, Escuela de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile
| | - Luc DesGroseillers
- Department of Biochemistry and Molecular Medicine, University of Montreal, P.O. Box 6128, Station Centre Ville, Montreal, Québec H3C 3J7, Canada
| | - Andrew J Mouland
- HIV-1 RNA Trafficking Laboratory, Lady Davis Institute at the Jewish General Hospital, Montréal, Québec H3T 1E2, Canada
- Department of Medicine, McGill University, Montréal, Québec H4A 3J1, Canada
| | - Marcelo López-Lastra
- Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Departamento de Enfermedades Infecciosas e Inmunología Pediátrica, Escuela de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile
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9
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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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10
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Barrera A, Ramos H, Vera-Otarola J, Fernández-García L, Angulo J, Olguín V, Pino K, Mouland AJ, López-Lastra M. Post-translational modifications of hnRNP A1 differentially modulate retroviral IRES-mediated translation initiation. Nucleic Acids Res 2020; 48:10479-10499. [PMID: 32960212 PMCID: PMC7544202 DOI: 10.1093/nar/gkaa765] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2019] [Revised: 08/09/2020] [Accepted: 09/02/2020] [Indexed: 12/20/2022] Open
Abstract
The full-length mRNAs of the human immunodeficiency virus type-1 (HIV-1), the human T-cell lymphotropic virus type-1 (HTLV-1), and the mouse mammary tumor virus (MMTV) harbor IRESs. The activity of the retroviral-IRESs requires IRES-transacting factors (ITAFs), being hnRNP A1, a known ITAF for the HIV-1 IRES. In this study, we show that hnRNP A1 is also an ITAF for the HTLV-1 and MMTV IRESs. The MMTV IRES proved to be more responsive to hnRNP A1 than either the HTLV-1 or the HIV-1 IRESs. The impact of post-translational modifications of hnRNP A1 on HIV-1, HTLV-1 and MMTV IRES activity was also assessed. Results show that the HIV-1 and HTLV-1 IRESs were equally responsive to hnRNP A1 and its phosphorylation mutants S4A/S6A, S4D/S6D and S199A/D. However, the S4D/S6D mutant stimulated the activity from the MMTV-IRES to levels significantly higher than the wild type hnRNP A1. PRMT5-induced symmetrical di-methylation of arginine residues of hnRNP A1 enabled the ITAF to stimulate the HIV-1 and HTLV-1 IRESs while reducing the stimulatory ability of the ITAF over the MMTV IRES. We conclude that retroviral IRES activity is not only dependent on the recruited ITAFs but also relies on how these proteins are modified at the post-translational level.
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Affiliation(s)
- Aldo Barrera
- Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Departamento de Enfermedades Infecciosas e Inmunología Pediátrica, Escuela de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile
| | - Hade Ramos
- Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Departamento de Enfermedades Infecciosas e Inmunología Pediátrica, Escuela de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile
| | - Jorge Vera-Otarola
- Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Departamento de Enfermedades Infecciosas e Inmunología Pediátrica, Escuela de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile
| | - Leandro Fernández-García
- Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Departamento de Enfermedades Infecciosas e Inmunología Pediátrica, Escuela de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile
| | - Jenniffer Angulo
- Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Departamento de Enfermedades Infecciosas e Inmunología Pediátrica, Escuela de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile
| | - Valeria Olguín
- Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Departamento de Enfermedades Infecciosas e Inmunología Pediátrica, Escuela de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile
| | - Karla Pino
- Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Departamento de Enfermedades Infecciosas e Inmunología Pediátrica, Escuela de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile
| | - Andrew J Mouland
- HIV-1 RNA Trafficking Laboratory, Lady Davis Institute at the Jewish General Hospital, Montréal, Québec H3T 1E2, Canada
- Department of Medicine, McGill University, Montréal, Québec H4A 3J1, Canada
| | - Marcelo López-Lastra
- Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Departamento de Enfermedades Infecciosas e Inmunología Pediátrica, Escuela de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile
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11
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Barrera A, Olguín V, Vera-Otarola J, López-Lastra M. Cap-independent translation initiation of the unspliced RNA of retroviruses. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2020; 1863:194583. [PMID: 32450258 DOI: 10.1016/j.bbagrm.2020.194583] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 05/12/2020] [Accepted: 05/18/2020] [Indexed: 12/12/2022]
Abstract
Retroviruses are a unique family of RNA viruses that utilize a virally encoded reverse transcriptase (RT) to replicate their genomic RNA (gRNA) through a proviral DNA intermediate. The provirus is permanently integrated into the host cell chromosome and is expressed by the host cell transcription, RNA processing, and translation machinery. Retroviral messenger RNAs (mRNAs) entirely resemble a cellular mRNA as they have a 5'cap structure, 5'untranslated region (UTR), an open reading frame (ORF), 3'UTR, and a 3'poly(A) tail. The primary transcription product interacts with the cellular RNA processing machinery and is spliced, exported to the cytoplasm, and translated. However, a proportion of the pre-mRNA subverts typical RNA processing giving rise to the full-length RNA. In the cytoplasm, the full-length retroviral RNA fulfills a dual role acting as mRNA and as the gRNA. Simple retroviruses generate two pools of full-length RNA, one for each purpose. However, complex retroviruses have a single pool of full-length RNA, which is destined for translation or encapsidation. As for eukaryotic mRNAs, translational control of retroviral protein synthesis is mostly exerted at the step of initiation. Interestingly, some retroviral mRNAs, both simple and complex, use a dual mechanism to initiate protein synthesis, a cap-dependent initiation mechanism, or via internal initiation using an internal ribosome entry site (IRES). In this review, we describe and discuss data regarding the molecular mechanism driving the canonical cap-dependent and IRES-mediated translation initiation for retroviral mRNA, focusing the discussion mainly on the most studied retroviral mRNA, the HIV-1 mRNA.
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Affiliation(s)
- Aldo Barrera
- Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Centro de Investigaciones Médicas, Departamento de Enfermedades Infecciosas e Inmunología Pediátrica, Escuela de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile
| | - Valeria Olguín
- Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Centro de Investigaciones Médicas, Departamento de Enfermedades Infecciosas e Inmunología Pediátrica, Escuela de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile
| | - Jorge Vera-Otarola
- Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Centro de Investigaciones Médicas, Departamento de Enfermedades Infecciosas e Inmunología Pediátrica, Escuela de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile
| | - Marcelo López-Lastra
- Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Centro de Investigaciones Médicas, Departamento de Enfermedades Infecciosas e Inmunología Pediátrica, Escuela de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile.
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12
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Palavecino CE, Carrasco-Véliz N, Quest AFG, Garrido MP, Valenzuela-Valderrama M. The 5' untranslated region of the anti-apoptotic protein Survivin contains an inhibitory upstream AUG codon. Biochem Biophys Res Commun 2020; 526:898-905. [PMID: 32279998 DOI: 10.1016/j.bbrc.2020.03.160] [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: 03/13/2020] [Accepted: 03/28/2020] [Indexed: 12/20/2022]
Abstract
Survivin (BIRC5) is an anti-apoptotic protein that is important in cancer. Mechanisms responsible for controlling Survivin levels in cells include transcriptional regulation and modulation of protein stability via post-translational modifications; however to date, translational control has been poorly studied. Here, we focused particularly on the primary control elements present in the Survivin 5' untranslated region (5'UTR). Bioinformatic analysis of ribosome occupancy on the Survivin 5'UTR revealed the presence of elongating ribosomes upstream of the canonical initiator AUG, suggesting an alternative upstream initiator AUG (uAUG) might exist. This uAUG was found out-of-frame at position -71 and appeared as a conserved element in mammals. RACE analysis revealed different transcriptional start sites for BIRC5, which indicated that translational control by this uAUG is restricted to longer 5'UTR variants. We studied the activity of the uAUG in different cell types by cloning the Survivin 5'UTR DNA sequence (wild-type and mutated variants) upstream of renilla luciferase (RLuc) into a pcDNA3 plasmid. Changes in RLuc activity were determined by luminescence assays and Western blotting. Results showed that when this uAUG was mutated to AUU or AGG in the cloned Survivin 5'UTR, RLuc activity was significantly increased. Similar results were obtained when uAUG was positioned inframe with the RLuc initiator AUG. Immunodetection of Renilla (35 kDa) by Western blotting revealed the presence of a second band (37 kDa approximately) in cells transfected with the Inframe reporter constructs, indicating that the uAUG was functional in our experimental conditions. In conclusion, our experimental data demonstrate the presence of an alternative and inhibitory initiator uAUG in the Survivin 5' UTR. This inhibitory uAUG may help understanding how Survivin expression is downregulated under physiological or pathological conditions.
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Affiliation(s)
- Christian E Palavecino
- Laboratorio de Microbiología Celular, Instituto de Investigación e Innovación en Salud, Facultad de Ciencias de la Salud, Universidad Central de Chile, Lord Cochrane 418, Santiago, 8320000, Chile
| | - Nicolás Carrasco-Véliz
- Laboratorio de Microbiología Celular, Instituto de Investigación e Innovación en Salud, Facultad de Ciencias de la Salud, Universidad Central de Chile, Lord Cochrane 418, Santiago, 8320000, Chile
| | - Andrew F G Quest
- Centro de Estudios Avanzados en Enfermedades Crónicas (ACCDiS), Sergio Livingstone 1007, Independencia, 8380492, Santiago, Chile; Laboratorio de Comunicaciones Celulares, Centro de Estudios en Ejercicio, Metabolismo y Cáncer (CEMC), Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Avenida Independencia 1027, Independencia, 8380453, Chile
| | - Maritza P Garrido
- Laboratorio de Endocrinología y Biología de la Reproducción, Departamento de Obstetricia y Ginecología, Hospital Clínico Universidad de Chile, Avenida Santos Dumont 999, Independencia, 8380456, Chile
| | - Manuel Valenzuela-Valderrama
- Laboratorio de Microbiología Celular, Instituto de Investigación e Innovación en Salud, Facultad de Ciencias de la Salud, Universidad Central de Chile, Lord Cochrane 418, Santiago, 8320000, Chile; Centro de Estudios Avanzados en Enfermedades Crónicas (ACCDiS), Sergio Livingstone 1007, Independencia, 8380492, Santiago, Chile.
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13
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Ishaq M, Marshall H, Natarajan V. GADD34 attenuates HIV-1 replication by viral 5'-UTR TAR RNA-mediated translational inhibition. Virology 2020; 540:119-131. [PMID: 31778897 PMCID: PMC6957764 DOI: 10.1016/j.virol.2019.11.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Revised: 11/07/2019] [Accepted: 11/08/2019] [Indexed: 10/25/2022]
Abstract
Role of GADD34, a protein that is induced following cellular stress, in HIV-1 replication was investigated. GADD34 was induced during the late phase of HIV-1 infection. siRNA-knockdown of GADD34 stimulated whereas overexpression of GADD34 inhibited HIV-1 replication. GADD34 N-terminal ER-binding-helix amino acid region 1-192 alone was found to be sufficient for the inhibition of HIV-1 replication whereas protein-phosphatase -1-binding domain and eIF-2α-phosphatase activity of GADD34 were not crucial for anti-HIV-1 activity. GADD34 did not alter the HIV-1 RNA levels but reduced the viral protein expression suggesting that GADD34 interferes in HIV protein synthesis. Studies on the effect of HIV-1-5'-UTR and its mutants on a human promoter-driven luciferase expression indicated that GADD34-inhibition was mediated by 5'-UTR/TAR RNA, probably by modulating TAR RNA structure. In summary, our data support a novel function of GADD34 as a putative anti-HIV-1 restriction factor.
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Affiliation(s)
- Mohammad Ishaq
- Laboratory of Molecular Cell Biology, Leidos Biomedical Research Inc, Frederick National Laboratory for Cancer Research, P.O. Box B, Frederick, MD, 21702, USA.
| | - Heather Marshall
- Laboratory of Molecular Cell Biology, Leidos Biomedical Research Inc, Frederick National Laboratory for Cancer Research, P.O. Box B, Frederick, MD, 21702, USA
| | - Ven Natarajan
- Laboratory of Molecular Cell Biology, Leidos Biomedical Research Inc, Frederick National Laboratory for Cancer Research, P.O. Box B, Frederick, MD, 21702, USA.
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14
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Cáceres CJ, Angulo J, Lowy F, Contreras N, Walters B, Olivares E, Allouche D, Merviel A, Pino K, Sargueil B, Thompson SR, López-Lastra M. Non-canonical translation initiation of the spliced mRNA encoding the human T-cell leukemia virus type 1 basic leucine zipper protein. Nucleic Acids Res 2019; 46:11030-11047. [PMID: 30215750 PMCID: PMC6237760 DOI: 10.1093/nar/gky802] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 08/28/2018] [Indexed: 02/06/2023] Open
Abstract
Human T-cell leukemia virus type 1 (HTLV-1) is the etiological agent of adult T-cell leukemia (ATL). The HTLV-1 basic leucine zipper protein (HBZ) is expressed in all cases of ATL and is directly associated with virus pathogenicity. The two isoforms of the HBZ protein are synthesized from antisense messenger RNAs (mRNAs) that are either spliced (sHBZ) or unspliced (usHBZ) versions of the HBZ transcript. The sHBZ and usHBZ mRNAs have entirely different 5′untranslated regions (5′UTR) and are differentially expressed in cells, with the sHBZ protein being more abundant. Here, we show that differential expression of the HBZ isoforms is regulated at the translational level. Translation initiation of the usHBZ mRNA relies on a cap-dependent mechanism, while the sHBZ mRNA uses internal initiation. Based on the structural data for the sHBZ 5′UTR generated by SHAPE in combination with 5′ and 3′ deletion mutants, the minimal region harboring IRES activity was mapped to the 5′end of the sHBZ mRNA. In addition, the sHBZ IRES recruited the 40S ribosomal subunit upstream of the initiation codon, and IRES activity was found to be dependent on the ribosomal protein eS25 and eIF5A.
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Affiliation(s)
- C Joaquín Cáceres
- Departamento de Enfermedades Infecciosas e Inmunología Pediátrica, Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Centro de Investigaciones Médicas, Escuela de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile
| | - Jenniffer Angulo
- Departamento de Enfermedades Infecciosas e Inmunología Pediátrica, Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Centro de Investigaciones Médicas, Escuela de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile
| | - Fernando Lowy
- Departamento de Enfermedades Infecciosas e Inmunología Pediátrica, Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Centro de Investigaciones Médicas, Escuela de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile
| | - Nataly Contreras
- Departamento de Enfermedades Infecciosas e Inmunología Pediátrica, Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Centro de Investigaciones Médicas, Escuela de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile
| | - Beth Walters
- Department of Microbiology, University of Alabama at Birmingham, Birmingham AL 35294, USA
| | - Eduardo Olivares
- Departamento de Enfermedades Infecciosas e Inmunología Pediátrica, Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Centro de Investigaciones Médicas, Escuela de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile
| | - Delphine Allouche
- CNRS UMR 8015, Laboratoire de cristallographie et RMN Biologique, Université Paris Descartes, 4 avenue de l'Observatoire, 75270 Paris Cedex 06, France
| | - Anne Merviel
- CNRS UMR 8015, Laboratoire de cristallographie et RMN Biologique, Université Paris Descartes, 4 avenue de l'Observatoire, 75270 Paris Cedex 06, France
| | - Karla Pino
- Departamento de Enfermedades Infecciosas e Inmunología Pediátrica, Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Centro de Investigaciones Médicas, Escuela de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile
| | - Bruno Sargueil
- CNRS UMR 8015, Laboratoire de cristallographie et RMN Biologique, Université Paris Descartes, 4 avenue de l'Observatoire, 75270 Paris Cedex 06, France
| | - Sunnie R Thompson
- Department of Microbiology, University of Alabama at Birmingham, Birmingham AL 35294, USA
| | - Marcelo López-Lastra
- Departamento de Enfermedades Infecciosas e Inmunología Pediátrica, Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Centro de Investigaciones Médicas, Escuela de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile
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15
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Focus on Translation Initiation of the HIV-1 mRNAs. Int J Mol Sci 2018; 20:ijms20010101. [PMID: 30597859 PMCID: PMC6337239 DOI: 10.3390/ijms20010101] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Revised: 12/21/2018] [Accepted: 12/22/2018] [Indexed: 01/04/2023] Open
Abstract
To replicate and disseminate, viruses need to manipulate and modify the cellular machinery for their own benefit. We are interested in translation, which is one of the key steps of gene expression and viruses that have developed several strategies to hijack the ribosomal complex. The type 1 human immunodeficiency virus is a good paradigm to understand the great diversity of translational control. Indeed, scanning, leaky scanning, internal ribosome entry sites, and adenosine methylation are used by ribosomes to translate spliced and unspliced HIV-1 mRNAs, and some require specific cellular factors, such as the DDX3 helicase, that mediate mRNA export and translation. In addition, some viral and cellular proteins, including the HIV-1 Tat protein, also regulate protein synthesis through targeting the protein kinase PKR, which once activated, is able to phosphorylate the eukaryotic translation initiation factor eIF2α, which results in the inhibition of cellular mRNAs translation. Finally, the infection alters the integrity of several cellular proteins, including initiation factors, that directly or indirectly regulates translation events. In this review, we will provide a global overview of the current situation of how the HIV-1 mRNAs interact with the host cellular environment to produce viral proteins.
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16
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Mailliot J, Martin F. Viral internal ribosomal entry sites: four classes for one goal. WILEY INTERDISCIPLINARY REVIEWS. RNA 2018; 9. [PMID: 29193740 DOI: 10.1002/wrna.1458] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Revised: 09/19/2017] [Accepted: 10/02/2017] [Indexed: 12/22/2022]
Abstract
To ensure efficient propagation, viruses need to rapidly produce viral proteins after cell entrance. Since viral genomes do not encode any components of the protein biosynthesis machinery, viral proteins must be produced by the host cell. To hi-jack the host cellular translation, viruses use a great variety of distinct strategies. Many single-stranded positive-sensed RNA viruses contain so-called internal ribosome entry sites (IRESs). IRESs are structural RNA motifs that have evolved to specific folds that recruit the host ribosomes on the viral coding sequences in order to synthesize viral proteins. In host canonical translation, recruitment of the translation machinery components is essentially guided by the 5' cap (m7 G) of mRNA. In contrast, IRESs are able to promote efficient ribosome assembly internally and in cap-independent manner. IRESs have been categorized into four classes, based on their length, nucleotide sequence, secondary and tertiary structures, as well as their mode of action. Classes I and II require the assistance of cellular auxiliary factors, the eukaryotic intiation factors (eIF), for efficient ribosome assembly. Class III IRESs require only a subset of eIFs whereas Class IV, which are the more compact, can promote translation without any eIFs. Extensive functional and structural investigations of IRESs over the past decades have allowed a better understanding of their mode of action for viral translation. Because viral translation has a pivotal role in the infectious program, IRESs are therefore attractive targets for therapeutic purposes. WIREs RNA 2018, 9:e1458. doi: 10.1002/wrna.1458 This article is categorized under: Translation > Ribosome Structure/Function Translation > Translation Mechanisms RNA Interactions with Proteins and Other Molecules > RNA-Protein Complexes.
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Affiliation(s)
- Justine Mailliot
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS UMR7104, INSERM U964, Illkirch-Graffenstaden, France
| | - Franck Martin
- Institut de Biologie Moléculaire et Cellulaire, "Architecture et Réactivité de l'ARN" CNRS UPR9002, Université De Strasbourg, Strasbourg, France
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Boeras I, Seufzer B, Brady S, Rendahl A, Heng X, Boris-Lawrie K. The basal translation rate of authentic HIV-1 RNA is regulated by 5'UTR nt-pairings at junction of R and U5. Sci Rep 2017; 7:6902. [PMID: 28761163 PMCID: PMC5537239 DOI: 10.1038/s41598-017-06883-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Accepted: 06/19/2017] [Indexed: 11/25/2022] Open
Abstract
The paradigm protein synthesis rate is regulated by structural complexity of the 5′untranslated region (UTR) derives from bacterial and other riboswitches. In-solution, HIV-1 5′UTR forms two interchangeable long-range nucleotide (nt) -pairings, one sequesters the gag start codon promoting dimerization while the other sequesters the dimer initiation signal preventing dimerization. While the effect of these nt-pairings on dimerization and packaging has been documented their effect on authentic HIV translation in cellulo has remained elusive until now. HIVNL4-3 5′UTR substitutions were designed to individually stabilize the dimer-prone or monomer-prone conformations, validated in-solution, and introduced to molecular clones. The effect of 5′UTR conformation on ribosome loading to HIV unspliced RNA and rate of Gag polypeptide synthesis was quantified in cellulo. Monomer- and dimer-prone 5′UTRs displayed equivalent, basal rate of translation. Gain-of-function substitution U103, in conjunction with previously defined nt-pairings that reorient AUG to flexible nt-pairing, significantly activated the translation rate, indicating the basal translation rate is under positive selection. The observed translation up-mutation focuses attention to nt-pairings at the junction of R and U5, a poorly characterized structure upstream of the characterized HIV riboswitch and demonstrates the basal translation rate of authentic HIV RNA is regulated independently of monomer:dimer equilibrium of the 5′UTR.
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Affiliation(s)
- I Boeras
- University of Minnesota, Department of Veterinary and Biomedical Sciences, 1971 Commonwealth, Saint Paul, MN, 55108, USA
| | - B Seufzer
- University of Minnesota, Department of Veterinary and Biomedical Sciences, 1971 Commonwealth, Saint Paul, MN, 55108, USA
| | - S Brady
- University of Missouri, Department of Biochemistry, 503 S. College Ave, Columbia, MO, 65211, USA
| | - A Rendahl
- University of Minnesota, Department of Veterinary and Biomedical Sciences, 1971 Commonwealth, Saint Paul, MN, 55108, USA
| | - X Heng
- University of Missouri, Department of Biochemistry, 503 S. College Ave, Columbia, MO, 65211, USA.
| | - K Boris-Lawrie
- University of Minnesota, Department of Veterinary and Biomedical Sciences, 1971 Commonwealth, Saint Paul, MN, 55108, USA.
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18
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Regulation of human immunodeficiency virus type 1 (HIV-1) mRNA translation. Biochem Soc Trans 2017; 45:353-364. [PMID: 28408475 DOI: 10.1042/bst20160357] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 01/06/2017] [Accepted: 01/11/2017] [Indexed: 12/17/2022]
Abstract
Human immunodeficiency virus type 1 (HIV-1) mRNA translation is a complex process that uses the host translation machinery to synthesise viral proteins. Several mechanisms for HIV-1 mRNA translation initiation have been proposed including (1) cap-dependent, eIF4E-dependent, (2) cap-dependent, cap-binding complex-dependent, (3) internal ribosome entry sites, and (4) ribosome shunting. While these mechanisms promote HIV-1 mRNA translation in the context of in vitro systems and subgenomic constructs, there are substantial knowledge gaps in understanding how they regulate viral protein production in the context of full-length virus infection. In this review, we will summarise the different translation mechanisms used by HIV-1 mRNAs and the challenges in understanding how they regulate protein synthesis during viral infection.
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19
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Cáceres CJ, Angulo J, Contreras N, Pino K, Vera-Otarola J, López-Lastra M. Targeting deoxyhypusine hydroxylase activity impairs cap-independent translation initiation driven by the 5'untranslated region of the HIV-1, HTLV-1, and MMTV mRNAs. Antiviral Res 2016; 134:192-206. [PMID: 27633452 DOI: 10.1016/j.antiviral.2016.09.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Accepted: 09/12/2016] [Indexed: 12/14/2022]
Abstract
Replication of the human immunodeficiency virus type 1 (HIV-1) is dependent on eIF5A hypusination. Hypusine is formed post-translationally on the eIF5A precursor by two consecutive enzymatic steps; a reversible reaction involving the enzyme deoxyhypusine synthase (DHS) and an irreversible step involving the enzyme deoxyhypusine hydroxylase (DOHH). In this study we explored the effect of inhibiting DOHH activity and therefore eIF5A hypusination, on HIV-1 gene expression. Results show that the expression of proteins from an HIV-1 molecular clone is reduced when DOHH activity is inhibited by Deferiprone (DFP) or Ciclopirox (CPX). Next we evaluated the requirement of DOHH activity for internal ribosome entry site (IRES)-mediated translation initiation driven by the 5'untranslated region (5'UTR) of the full length HIV-1 mRNA. Results show that HIV-1 IRES activity relies on DOHH protein concentration and enzymatic activity. Similar results were obtained for IRES-dependent translation initiation mediated by 5'UTR of the human T-cell lymphotropic virus type 1 (HTLV-1) and the mouse mammary tumor virus (MMTV) mRNAs. Interestingly, activity of the poliovirus IRES, was less sensitive to the targeting of DOHH suggesting that not all viral IRESs are equally dependent on the cellular concentration or the activity of DOHH. In summary we present evidence indicating that the cellular concentration of DOHH and its enzymatic activity play a role in HIV-1, HTLV-1 and MMTV IRES-mediated translation initiation.
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Affiliation(s)
- C Joaquín Cáceres
- Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Departamento de Enfermedades Infecciosas e Inmunología Pediátrica, Escuela de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile
| | - Jenniffer Angulo
- Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Departamento de Enfermedades Infecciosas e Inmunología Pediátrica, Escuela de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile
| | - Nataly Contreras
- Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Departamento de Enfermedades Infecciosas e Inmunología Pediátrica, Escuela de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile
| | - Karla Pino
- Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Departamento de Enfermedades Infecciosas e Inmunología Pediátrica, Escuela de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile
| | - Jorge Vera-Otarola
- Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Departamento de Enfermedades Infecciosas e Inmunología Pediátrica, Escuela de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile
| | - Marcelo López-Lastra
- Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Departamento de Enfermedades Infecciosas e Inmunología Pediátrica, Escuela de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile.
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20
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Daudé C, Décimo D, Trabaud MA, André P, Ohlmann T, de Breyne S. HIV-1 sequences isolated from patients promote expression of shorter isoforms of the Gag polyprotein. Arch Virol 2016; 161:3495-3507. [PMID: 27659676 DOI: 10.1007/s00705-016-3073-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 09/15/2016] [Indexed: 12/24/2022]
Abstract
Human immunodeficiency virus type 1 (HIV-1) unspliced mRNA drives the expression of both Gag and Gag-Pol polyproteins by using both cap- and internal ribosome entry site (IRES)-dependent translation initiation mechanisms. An IRES has been described in the matrix coding region that is involved in the production of shorter isoforms of Gag. However, up to now, this has only been shown with sequences derived from the HIV-1 laboratory strains (NL4.3 and HXB2) and never from clinical HIV-1 isolates. We have isolated ~70 sequences from HIV-1-positive patients that we have sequenced and cloned into an expression vector to monitor their ability to drive translation of Gag p55 and the shorter isoforms both in vitro and ex vivo. The results indicate that (1) the translational efficiency from the AUG-p55 varies significantly among the different isolates; (2) expression initiated at AUG-p40 codon is independent of translation initiation at the AUG-p55 triplet; and (3) all sequences promote expression of shorter Gag isoforms, in particular in Jurkat T cells, in which internal initiation occurs exclusively and directly at the AUG-p40 codon. The composition of the first ~800 nucleotides of the HIV-1 unspliced mRNA modulates the expression initiated both at the AUG-p55 and AUG-p40 codons and may impact viral production and replication. Interestingly, the AUG-p40 codon and its surrounding nucleotide context are conserved amongst clinical isolates and are used as a translation initiation site to produce a shorter Gag isoform.
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Affiliation(s)
- Christelle Daudé
- CIRI, International Center for Infectiology Research, Université de Lyon, 46 Allée d'Italie, 69364, Lyon, France.,Inserm, U1111, 46 Allée d'Italie, 69364, Lyon, France.,Ecole Normale Supérieure de Lyon, 46 Allée d'Italie, 69364, Lyon, France.,Université Claude Bernard Lyon 1, 46 Allée d'Italie, 69364, Lyon, France.,CNRS, UMR5308, 46 Allée d'Italie, 69364, Lyon, France.,Waking team, Lyon Neuroscience Research Center, CNRS UMR5292, INSERM U1028, Université Claude Bernard, Lyon, France
| | - Didier Décimo
- CIRI, International Center for Infectiology Research, Université de Lyon, 46 Allée d'Italie, 69364, Lyon, France.,Inserm, U1111, 46 Allée d'Italie, 69364, Lyon, France.,Ecole Normale Supérieure de Lyon, 46 Allée d'Italie, 69364, Lyon, France.,Université Claude Bernard Lyon 1, 46 Allée d'Italie, 69364, Lyon, France.,CNRS, UMR5308, 46 Allée d'Italie, 69364, Lyon, France
| | | | - Patrice André
- CIRI, International Center for Infectiology Research, Université de Lyon, 46 Allée d'Italie, 69364, Lyon, France.,Inserm, U1111, 46 Allée d'Italie, 69364, Lyon, France.,Ecole Normale Supérieure de Lyon, 46 Allée d'Italie, 69364, Lyon, France.,Université Claude Bernard Lyon 1, 46 Allée d'Italie, 69364, Lyon, France.,CNRS, UMR5308, 46 Allée d'Italie, 69364, Lyon, France.,Hospices Civils de Lyon, Lyon, France
| | - Théophile Ohlmann
- CIRI, International Center for Infectiology Research, Université de Lyon, 46 Allée d'Italie, 69364, Lyon, France. .,Inserm, U1111, 46 Allée d'Italie, 69364, Lyon, France. .,Ecole Normale Supérieure de Lyon, 46 Allée d'Italie, 69364, Lyon, France. .,Université Claude Bernard Lyon 1, 46 Allée d'Italie, 69364, Lyon, France. .,CNRS, UMR5308, 46 Allée d'Italie, 69364, Lyon, France. .,Hospices Civils de Lyon, Lyon, France.
| | - Sylvain de Breyne
- CIRI, International Center for Infectiology Research, Université de Lyon, 46 Allée d'Italie, 69364, Lyon, France. .,Inserm, U1111, 46 Allée d'Italie, 69364, Lyon, France. .,Ecole Normale Supérieure de Lyon, 46 Allée d'Italie, 69364, Lyon, France. .,Université Claude Bernard Lyon 1, 46 Allée d'Italie, 69364, Lyon, France. .,CNRS, UMR5308, 46 Allée d'Italie, 69364, Lyon, France.
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21
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Carvajal F, Vallejos M, Walters B, Contreras N, Hertz MI, Olivares E, Cáceres CJ, Pino K, Letelier A, Thompson SR, López-Lastra M. Structural domains within the HIV-1 mRNA and the ribosomal protein S25 influence cap-independent translation initiation. FEBS J 2016; 283:2508-27. [PMID: 27191820 DOI: 10.1111/febs.13756] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Revised: 04/28/2016] [Accepted: 05/13/2016] [Indexed: 12/14/2022]
Abstract
The 5' leader of the HIV-1 genomic RNA is a multifunctional region that folds into secondary/tertiary structures that regulate multiple processes during viral replication including translation initiation. In this work, we examine the internal ribosome entry site (IRES) located in the 5' leader that drives translation initiation of the viral Gag protein under conditions that hinder cap-dependent translation initiation. We show that activity of the HIV-1 IRES relies on ribosomal protein S25 (eS25). Additionally, a mechanistic and mutational analysis revealed that the HIV-1 IRES is modular in nature and that once the 40S ribosomal subunit is recruited to the IRES, translation initiates without the need of ribosome scanning. These findings elucidate a mechanism of initiation by the HIV-1 IRES whereby a number of highly structured sites present within the HIV-1 5' leader leads to the recruitment of the 40S subunit directly at the site of initiation of protein synthesis.
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Affiliation(s)
- Felipe Carvajal
- Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Departamento de Enfermedades Infecciosas e Inmunología Pediátrica, Escuela de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Maricarmen Vallejos
- Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Departamento de Enfermedades Infecciosas e Inmunología Pediátrica, Escuela de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Beth Walters
- Department of Microbiology, University of Alabama at Birmingham, AL, USA
| | - Nataly Contreras
- Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Departamento de Enfermedades Infecciosas e Inmunología Pediátrica, Escuela de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Marla I Hertz
- Department of Microbiology, University of Alabama at Birmingham, AL, USA
| | - Eduardo Olivares
- Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Departamento de Enfermedades Infecciosas e Inmunología Pediátrica, Escuela de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Carlos J Cáceres
- Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Departamento de Enfermedades Infecciosas e Inmunología Pediátrica, Escuela de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Karla Pino
- Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Departamento de Enfermedades Infecciosas e Inmunología Pediátrica, Escuela de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Alejandro Letelier
- Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Departamento de Enfermedades Infecciosas e Inmunología Pediátrica, Escuela de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Sunnie R Thompson
- Department of Microbiology, University of Alabama at Birmingham, AL, USA
| | - Marcelo López-Lastra
- Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Departamento de Enfermedades Infecciosas e Inmunología Pediátrica, Escuela de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
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22
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Smirnova VV, Terenin IM, Khutornenko AA, Andreev DE, Dmitriev SE, Shatsky IN. Does HIV-1 mRNA 5'-untranslated region bear an internal ribosome entry site? Biochimie 2016; 121:228-37. [DOI: 10.1016/j.biochi.2015.12.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Accepted: 12/11/2015] [Indexed: 12/18/2022]
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23
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Rojas-Araya B, Ohlmann T, Soto-Rifo R. Translational Control of the HIV Unspliced Genomic RNA. Viruses 2015; 7:4326-51. [PMID: 26247956 PMCID: PMC4576183 DOI: 10.3390/v7082822] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Revised: 05/18/2015] [Accepted: 07/17/2015] [Indexed: 01/16/2023] Open
Abstract
Post-transcriptional control in both HIV-1 and HIV-2 is a highly regulated process that commences in the nucleus of the host infected cell and finishes by the expression of viral proteins in the cytoplasm. Expression of the unspliced genomic RNA is particularly controlled at the level of RNA splicing, export, and translation. It appears increasingly obvious that all these steps are interconnected and they result in the building of a viral ribonucleoprotein complex (RNP) that must be efficiently translated in the cytosolic compartment. This review summarizes our knowledge about the genesis, localization, and expression of this viral RNP.
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Affiliation(s)
- Bárbara Rojas-Araya
- Molecular and Cellular Virology Laboratory, Program of Virology, Institute of Biomedical Sciences, Faculty of Medicine, University of Chile, Independencia 834100, Santiago, Chile.
| | - Théophile Ohlmann
- CIRI, International Center for Infectiology Research, Université de Lyon, Lyon 69007, France.
- Inserm, U1111, Lyon 69007, France.
- Ecole Normale Supérieure de Lyon, Lyon 69007, France.
- Université Lyon 1, Centre International de Recherche en Infectiologie, Lyon 69007, France.
- CNRS, UMR5308, Lyon 69007, France.
| | - Ricardo Soto-Rifo
- Molecular and Cellular Virology Laboratory, Program of Virology, Institute of Biomedical Sciences, Faculty of Medicine, University of Chile, Independencia 834100, Santiago, Chile.
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24
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Moss WN, Steitz JA. In silico discovery and modeling of non-coding RNA structure in viruses. Methods 2015; 91:48-56. [PMID: 26116541 DOI: 10.1016/j.ymeth.2015.06.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Revised: 06/17/2015] [Accepted: 06/22/2015] [Indexed: 11/30/2022] Open
Abstract
This review covers several computational methods for discovering structured non-coding RNAs in viruses and modeling their putative secondary structures. Here we will use examples from two target viruses to highlight these approaches: influenza A virus-a relatively small, segmented RNA virus; and Epstein-Barr virus-a relatively large DNA virus with a complex transcriptome. Each system has unique challenges to overcome and unique characteristics to exploit. From these particular cases, generically useful approaches can be derived for the study of additional viral targets.
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Affiliation(s)
- Walter N Moss
- Department of Molecular Biophysics and Biochemistry, Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT 06536, USA
| | - Joan A Steitz
- Department of Molecular Biophysics and Biochemistry, Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT 06536, USA.
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25
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Guerrero S, Batisse J, Libre C, Bernacchi S, Marquet R, Paillart JC. HIV-1 replication and the cellular eukaryotic translation apparatus. Viruses 2015; 7:199-218. [PMID: 25606970 PMCID: PMC4306834 DOI: 10.3390/v7010199] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Accepted: 01/12/2015] [Indexed: 12/13/2022] Open
Abstract
Eukaryotic translation is a complex process composed of three main steps: initiation, elongation, and termination. During infections by RNA- and DNA-viruses, the eukaryotic translation machinery is used to assure optimal viral protein synthesis. Human immunodeficiency virus type I (HIV-1) uses several non-canonical pathways to translate its own proteins, such as leaky scanning, frameshifting, shunt, and cap-independent mechanisms. Moreover, HIV-1 modulates the host translation machinery by targeting key translation factors and overcomes different cellular obstacles that affect protein translation. In this review, we describe how HIV-1 proteins target several components of the eukaryotic translation machinery, which consequently improves viral translation and replication.
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Affiliation(s)
- Santiago Guerrero
- Architecture et Réactivité de l'ARN, CNRS, Université de Strasbourg, Institut de Biologie Moléculaire et Cellulaire, 15 rue René Descartes, 67084 Strasbourg cedex, France.
| | - Julien Batisse
- Architecture et Réactivité de l'ARN, CNRS, Université de Strasbourg, Institut de Biologie Moléculaire et Cellulaire, 15 rue René Descartes, 67084 Strasbourg cedex, France.
| | - Camille Libre
- Architecture et Réactivité de l'ARN, CNRS, Université de Strasbourg, Institut de Biologie Moléculaire et Cellulaire, 15 rue René Descartes, 67084 Strasbourg cedex, France.
| | - Serena Bernacchi
- Architecture et Réactivité de l'ARN, CNRS, Université de Strasbourg, Institut de Biologie Moléculaire et Cellulaire, 15 rue René Descartes, 67084 Strasbourg cedex, France.
| | - Roland Marquet
- Architecture et Réactivité de l'ARN, CNRS, Université de Strasbourg, Institut de Biologie Moléculaire et Cellulaire, 15 rue René Descartes, 67084 Strasbourg cedex, France.
| | - Jean-Christophe Paillart
- Architecture et Réactivité de l'ARN, CNRS, Université de Strasbourg, Institut de Biologie Moléculaire et Cellulaire, 15 rue René Descartes, 67084 Strasbourg cedex, France.
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26
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Ohlmann T, Mengardi C, López-Lastra M. Translation initiation of the HIV-1 mRNA. ACTA ACUST UNITED AC 2014; 2:e960242. [PMID: 26779410 DOI: 10.4161/2169074x.2014.960242] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Revised: 05/23/2014] [Accepted: 06/17/2014] [Indexed: 12/17/2022]
Abstract
Translation initiation of the full-length mRNA of the human immunodeficiency virus can occur via several different mechanisms to maintain production of viral structural proteins throughout the replication cycle. HIV-1 viral protein synthesis can occur by the use of both a cap-dependant and IRES-driven mechanism depending on the physiological conditions of the cell and the status of the ongoing infection. For both of these mechanisms there is a need for several viral and cellular co-factors for optimal translation of the viral mRNA. In this review we will describe the mechanism used by the full-length mRNA to initiate translation highlighting the role of co-factors within this process. A particular emphasis will be given to the role of the DDX3 RNA helicase in HIV-1 mRNA translation initiation.
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Affiliation(s)
- Théophile Ohlmann
- CIRI; International Center for Infectiology Research; Université de Lyon; Lyon, France; Inserm; Lyon, France; Ecole Normale Supérieure de Lyon; Lyon, France; Université Lyon 1; Center International de Recherche en Infectiologie; Lyon, France; CNRS; Lyon, France
| | - Chloé Mengardi
- CIRI; International Center for Infectiology Research; Université de Lyon; Lyon, France; Inserm; Lyon, France; Ecole Normale Supérieure de Lyon; Lyon, France; Université Lyon 1; Center International de Recherche en Infectiologie; Lyon, France; CNRS; Lyon, France
| | - Marcelo López-Lastra
- Laboratorio de Virología Molecular; Instituto Milenio de Inmunología e Inmunoterapia; Centro de Investigaciones Médicas; Escuela de Medicina; Pontificia Universidad Católica de Chile ; Santiago, Chile
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27
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Burugu S, Daher A, Meurs EF, Gatignol A. HIV-1 translation and its regulation by cellular factors PKR and PACT. Virus Res 2014; 193:65-77. [PMID: 25064266 DOI: 10.1016/j.virusres.2014.07.014] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Revised: 07/13/2014] [Accepted: 07/14/2014] [Indexed: 12/24/2022]
Abstract
The synthesis of proteins from viral mRNA is the first step towards viral assembly. Viruses are dependent upon the cellular translation machinery to synthesize their own proteins. The synthesis of proteins from the human immunodeficiency virus (HIV) type 1 and 2 RNAs utilize several alternative mechanisms. The regulation of viral protein production requires a constant interplay between viral requirements and the cell response to viral infection. Among the antiviral cell responses, the interferon-induced RNA activated protein kinase, PKR, regulates the cellular and viral translation. During HIV-1 infection, PKR activation is highly regulated by viral and cellular factors. The cellular TAR RNA Binding Protein, TRBP, the Adenosine Deaminase acting on RNA, ADAR1, and the PKR Activator, PACT, play important roles. Recent data show that PACT changes its function from activator to inhibitor in HIV-1 infected cells. Therefore, HIV-1 has evolved to replicate in cells in which TRBP, ADAR1 and PACT prevent PKR activation to allow efficient viral protein synthesis. This proper translation will initiate the assembly of viral particles.
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Affiliation(s)
- Samantha Burugu
- Virus-cell Interactions Laboratory, Lady Davis Institute for Medical Research, Montréal, QC, Canada; Department of Microbiology and Immunology, McGill University, Montréal, QC, Canada
| | - Aïcha Daher
- Virus-cell Interactions Laboratory, Lady Davis Institute for Medical Research, Montréal, QC, Canada
| | - Eliane F Meurs
- Institut Pasteur, Department of Virology, Hepacivirus and Innate Immunity Unit, Paris, France
| | - Anne Gatignol
- Virus-cell Interactions Laboratory, Lady Davis Institute for Medical Research, Montréal, QC, Canada; Department of Microbiology and Immunology, McGill University, Montréal, QC, Canada; Department of Medicine, Division of Experimental Medicine, McGill University, Montréal, QC, Canada.
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28
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The 5' untranslated region of the human T-cell lymphotropic virus type 1 mRNA enables cap-independent translation initiation. J Virol 2014; 88:5936-55. [PMID: 24623421 DOI: 10.1128/jvi.00279-14] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
UNLABELLED The human T-cell leukemia virus type 1 (HTLV-1) is a complex human retrovirus that causes adult T cell leukemia and of HTLV-associated myelopathy/tropical spastic paraparesis. The mRNA of some complex retroviruses, including the human and simian immunodeficiency viruses (HIV and SIV), can initiate translation using a canonical cap-dependent mechanism or through an internal ribosome entry site (IRES). In this study, we present strong evidence showing that like HIV-1 and SIV, the 5'-untranslated region (5'UTR) of the HTLV-1 full-length mRNA harbors an IRES. Cap-independent translational activity was evaluated and demonstrated using dual luciferase bicistronic mRNAs in rabbit reticulocyte lysate, in mammalian cell culture, and in Xenopus laevis oocytes. Characterization of the HTLV-1 IRES shows that its activity is dependent on the ribosomal protein S25 (RPS25) and that its function is highly sensitive to the drug edeine. Together, these findings suggest that the 5'UTR of the HTLV-1 full-length mRNA enables internal recruitment of the eukaryotic translation initiation complex. However, the recognition of the initiation codon requires ribosome scanning. These results suggest that, after internal recruitment by the HTLV-1 IRES, a scanning step takes place for the 40S ribosomal subunit to be positioned at the translation initiation codon. IMPORTANCE The mechanism by which retroviral mRNAs recruit the 40S ribosomal subunit internally is not understood. This study provides new insights into the mechanism of translation initiation used by the human T-cell lymphotropic virus type 1 (HTLV-1). The results show that the HTLV-1 mRNA can initiate translation via a noncanonical mechanism mediated by an internal ribosome entry site (IRES). This study also provides evidence showing the involvement of cellular proteins in HTLV-1 IRES-mediated translation initiation. Together, the data presented in this report significantly contribute to the understanding of HTLV-1 gene expression.
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29
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Amorim R, Costa SM, Cavaleiro NP, da Silva EE, da Costa LJ. HIV-1 transcripts use IRES-initiation under conditions where Cap-dependent translation is restricted by poliovirus 2A protease. PLoS One 2014; 9:e88619. [PMID: 24520405 PMCID: PMC3919812 DOI: 10.1371/journal.pone.0088619] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Accepted: 01/14/2014] [Indexed: 11/18/2022] Open
Abstract
The 30 different species of mRNAs synthesized during the HIV-1 replication cycle are all capped and polyadenilated. Internal ribosome entry sites have been recognized in the 5' untranslated region of some mRNA species of HIV-1, which would contribute to an alternative mechanism of initiation of mRNA translation. However, the Cap-dependent translation is assumed to be the main mechanism driving the initiation of HIV-1 protein synthesis. In this work, we describe a cell system in which lower to higher levels of transient expression of the poliovirus 2A protease strongly inhibited cellular Cap-dependent translation with no toxic effect to the cells during a 72-hour time frame. In this system, the synthesis of HIV-1 proteins was inhibited in a temporal dose-dependent way. Higher levels of 2A protease expression severely inhibited HIV-1 protein synthesis during the first 24 hours of infection consequently inhibiting viral production and infectivity. Intermediate to lower levels of 2A Protease expression caused the inhibition of viral protein synthesis only during the first 48 hours of viral replication. After this period both protein synthesis and viral release were recovered to the control levels. However, the infectivity of viral progeny was still partially inhibited. These results indicate that two mechanisms of mRNA translation initiation contribute to the synthesis of HIV-1 proteins; during the first 24-48 hours of viral replication HIV-1 protein synthesis is strongly dependent on Cap-initiation, while at later time points IRES-driven translation initiation is sufficient to produce high amounts of viral particles.
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Affiliation(s)
- Raquel Amorim
- Instituto de Microbiologia, Departamento de Virologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Sara Mesquita Costa
- Instituto de Microbiologia, Departamento de Virologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Nathalia Pereira Cavaleiro
- Instituto de Microbiologia, Departamento de Virologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Edson Elias da Silva
- Laboratório de Enterovírus, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
| | - Luciana Jesus da Costa
- Instituto de Microbiologia, Departamento de Virologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
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30
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Chang W, Jääskeläinen M, Li SP, Schulman AH. BARE retrotransposons are translated and replicated via distinct RNA pools. PLoS One 2013; 8:e72270. [PMID: 23940808 PMCID: PMC3735527 DOI: 10.1371/journal.pone.0072270] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Accepted: 07/14/2013] [Indexed: 01/02/2023] Open
Abstract
The replication of Long Terminal Repeat (LTR) retrotransposons, which can constitute over 80% of higher plant genomes, resembles that of retroviruses. A major question for retrotransposons and retroviruses is how the two conflicting roles of their transcripts, in translation and reverse transcription, are balanced. Here, we show that the BARE retrotransposon, despite its organization into just one open reading frame, produces three distinct classes of transcripts. One is capped, polyadenylated, and translated, but cannot be copied into cDNA. The second is not capped or polyadenylated, but is destined for packaging and ultimate reverse transcription. The third class is capped, polyadenylated, and spliced to favor production of a subgenomic RNA encoding only Gag, the protein forming virus-like particles. Moreover, the BARE2 subfamily, which cannot synthesize Gag and is parasitic on BARE1, does not produce the spliced sub-genomic RNA for translation but does make the replication competent transcripts, which are packaged into BARE1 particles. To our knowledge, this is first demonstration of distinct RNA pools for translation and transcription for any retrotransposon.
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Affiliation(s)
- Wei Chang
- Institute of Biotechnology, Viikki Biocenter, University of Helsinki, Helsinki, Finland
| | - Marko Jääskeläinen
- Institute of Biotechnology, Viikki Biocenter, University of Helsinki, Helsinki, Finland
| | - Song-ping Li
- Genome-Scale Biology Program, University of Helsinki, Biomedicum, Helsinki, Finland
| | - Alan H. Schulman
- Institute of Biotechnology, Viikki Biocenter, University of Helsinki, Helsinki, Finland
- Biotechnology and Food Research, MTT Agrifood Research Finland, Jokioinen, Finland
- * E-mail:
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Monette A, Valiente-Echeverría F, Rivero M, Cohen ÉA, Lopez-Lastra M, Mouland AJ. Dual mechanisms of translation initiation of the full-length HIV-1 mRNA contribute to gag synthesis. PLoS One 2013; 8:e68108. [PMID: 23861855 PMCID: PMC3702555 DOI: 10.1371/journal.pone.0068108] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Accepted: 05/25/2013] [Indexed: 01/01/2023] Open
Abstract
The precursor group-specific antigen (pr55Gag) is central to HIV-1 assembly. Its expression alone is sufficient to assemble into virus-like particles. It also selects the genomic RNA for encapsidation and is involved in several important virus-host interactions for viral assembly and restriction, making its synthesis essential for aspects of viral replication. Here, we show that the initiation of translation of the HIV-1 genomic RNA is mediated through both a cap-dependent and an internal ribosome entry site (IRES)-mediated mechanisms. In support of this notion, pr55Gag synthesis was maintained at 70% when cap-dependent translation initiation was blocked by the expression of eIF4G- and PABP targeting viral proteases in two in vitro systems and in HIV-1-expressing cells directly infected with poliovirus. While our data reveal that IRES-dependent translation of the viral genomic RNA ensures pr55Gag expression, the synthesis of other HIV-1 proteins, including that of pr160Gag/Pol, Vpr and Tat is suppressed early during progressive poliovirus infection. The data presented herein implies that the unspliced HIV-1 genomic RNA utilizes both cap-dependent and IRES-dependent translation initiation to supply pr55Gag for virus assembly and production.
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MESH Headings
- Cell Line
- Gene Expression Regulation, Viral
- Gene Order
- Genetic Vectors/genetics
- Genome, Viral
- HIV-1/genetics
- HIV-1/metabolism
- Humans
- Peptide Chain Initiation, Translational
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- RNA, Viral/genetics
- RNA, Viral/metabolism
- Regulatory Sequences, Ribonucleic Acid
- gag Gene Products, Human Immunodeficiency Virus/biosynthesis
- tat Gene Products, Human Immunodeficiency Virus/genetics
- tat Gene Products, Human Immunodeficiency Virus/metabolism
- vpr Gene Products, Human Immunodeficiency Virus/genetics
- vpr Gene Products, Human Immunodeficiency Virus/metabolism
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Affiliation(s)
- Anne Monette
- HIV-1 Trafficking Laboratory, Lady Davis Institute at the Jewish General Hospital, Montréal, Québec, Canada
- Department of Medicine, Division of Experimental Medicine, McGill University, Montreal, Quebec, Canada
| | - Fernando Valiente-Echeverría
- HIV-1 Trafficking Laboratory, Lady Davis Institute at the Jewish General Hospital, Montréal, Québec, Canada
- Department of Medicine, Division of Experimental Medicine, McGill University, Montreal, Quebec, Canada
| | - Matias Rivero
- Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Centro de Investigaciones Médicas, Escuela de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Éric A. Cohen
- Laboratory of Human Retrovirology, Institut de recherches cliniques de Montréal, Montréal, Quebec, Canada
| | - Marcelo Lopez-Lastra
- Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Centro de Investigaciones Médicas, Escuela de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
- * E-mail: (MLL); (AJM)
| | - Andrew J. Mouland
- HIV-1 Trafficking Laboratory, Lady Davis Institute at the Jewish General Hospital, Montréal, Québec, Canada
- Department of Medicine, Division of Experimental Medicine, McGill University, Montreal, Quebec, Canada
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada
- * E-mail: (MLL); (AJM)
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Valiente-Echeverría F, Vallejos M, Monette A, Pino K, Letelier A, Huidobro-Toro JP, Mouland AJ, López-Lastra M. A cis-acting element present within the Gag open reading frame negatively impacts on the activity of the HIV-1 IRES. PLoS One 2013; 8:e56962. [PMID: 23451120 PMCID: PMC3581557 DOI: 10.1371/journal.pone.0056962] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2012] [Accepted: 01/16/2013] [Indexed: 12/29/2022] Open
Abstract
Translation initiation from the human immunodeficiency virus type-1 (HIV-1) mRNA can occur through a cap or an IRES dependent mechanism. Cap-dependent translation initiation of the HIV-1 mRNA can be inhibited by the instability element (INS)-1, a cis-acting regulatory element present within the gag open reading frame (ORF). In this study we evaluated the impact of the INS-1 on HIV-1 IRES-mediated translation initiation. Using heterologous bicistronic mRNAs, we show that the INS-1 negatively impact on HIV-1 IRES-driven translation in in vitro and in cell-based experiments. Additionally, our results show that the inhibitory effect of the INS-1 is not general to all IRESes since it does not hinder translation driven by the HCV IRES. The inhibition by the INS-1 was partially rescued in cells by the overexpression of the viral Rev protein or hnRNPA1.
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Affiliation(s)
- Fernando Valiente-Echeverría
- Laboratorio de Virología Molecular, Instituto Milenio de Inmunología e Inmunoterapia, Centro de Investigaciones Médicas, Escuela de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
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de Breyne S, Soto-Rifo R, López-Lastra M, Ohlmann T. Translation initiation is driven by different mechanisms on the HIV-1 and HIV-2 genomic RNAs. Virus Res 2012; 171:366-81. [PMID: 23079111 DOI: 10.1016/j.virusres.2012.10.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Revised: 10/05/2012] [Accepted: 10/08/2012] [Indexed: 02/08/2023]
Abstract
The human immunodeficiency virus (HIV) unspliced full length genomic RNA possesses features of an eukaryotic cellular mRNA as it is capped at its 5' end and polyadenylated at its 3' extremity. This genomic RNA is used both for the production of the viral structural and enzymatic proteins (Gag and Pol, respectively) and as genome for encapsidation in the newly formed viral particle. Although both of these processes are critical for viral replication, they should be controlled in a timely manner for a coherent progression into the viral cycle. Some of this regulation is exerted at the level of translational control and takes place on the viral 5' untranslated region and the beginning of the gag coding region. In this review, we have focused on the different initiation mechanisms (cap- and internal ribosome entry site (IRES)-dependent) that are used by the HIV-1 and HIV-2 genomic RNAs and the cellular and viral factors that can modulate their expression. Interestingly, although HIV-1 and HIV-2 share many similarities in the overall clinical syndrome they produce, in some aspects of their replication cycle, and in the structure of their respective genome, they exhibit some differences in the way that ribosomes are recruited on the gag mRNA to initiate translation and produce the viral proteins; this will be discussed in the light of the literature.
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