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Duchon A, Hu WS. HIV-1 RNA genome packaging: it's G-rated. mBio 2024; 15:e0086123. [PMID: 38411060 PMCID: PMC11005445 DOI: 10.1128/mbio.00861-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/28/2024] Open
Abstract
A member of the Retroviridae, human immunodeficiency virus type 1 (HIV-1), uses the RNA genome packaged into nascent virions to transfer genetic information to its progeny. The genome packaging step is a highly regulated and extremely efficient process as a vast majority of virus particles contain two copies of full-length unspliced HIV-1 RNA that form a dimer. Thus, during virus assembly HIV-1 can identify and selectively encapsidate HIV-1 unspliced RNA from an abundant pool of cellular RNAs and various spliced HIV-1 RNAs. Several "G" features facilitate the packaging of a dimeric RNA genome. The viral polyprotein Gag orchestrates virus assembly and mediates RNA genome packaging. During this process, Gag preferentially binds unpaired guanosines within the highly structured 5' untranslated region (UTR) of HIV-1 RNA. In addition, the HIV-1 unspliced RNA provides a scaffold that promotes Gag:Gag interactions and virus assembly, thereby ensuring its packaging. Intriguingly, recent studies have shown that the use of different guanosines at the junction of U3 and R as transcription start sites results in HIV-1 unspliced RNA species with 99.9% identical sequences but dramatically distinct 5' UTR conformations. Consequently, one species of unspliced RNA is preferentially packaged over other nearly identical RNAs. These studies reveal how conformations affect the functions of HIV-1 RNA elements and the complex regulation of HIV-1 replication. In this review, we summarize cis- and trans-acting elements critical for HIV-1 RNA packaging, locations of Gag:RNA interactions that mediate genome encapsidation, and the effects of transcription start sites on the structure and packaging of HIV-1 RNA.
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Affiliation(s)
- Alice Duchon
- Viral Recombination Section, HIV Dynamics and Replication Program, National Cancer Institute, Frederick, Maryland, USA
| | - Wei-Shau Hu
- Viral Recombination Section, HIV Dynamics and Replication Program, National Cancer Institute, Frederick, Maryland, USA
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2
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Cunningham CL, Frye CJ, Makowski JA, Kensinger AH, Shine M, Milback EJ, Lackey PE, Evanseck JD, Mihailescu MR. Effect of the SARS-CoV-2 Delta-associated G15U mutation on the s2m element dimerization and its interactions with miR-1307-3p. RNA (NEW YORK, N.Y.) 2023; 29:1754-1771. [PMID: 37604684 PMCID: PMC10578481 DOI: 10.1261/rna.079627.123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 07/30/2023] [Indexed: 08/23/2023]
Abstract
The s2m, a highly conserved 41-nt hairpin structure in the SARS-CoV-2 genome, serves as an attractive therapeutic target that may have important roles in the virus life cycle or interactions with the host. However, the conserved s2m in Delta SARS-CoV-2, a previously dominant variant characterized by high infectivity and disease severity, has received relatively less attention than that of the original SARS-CoV-2 virus. The focus of this work is to identify and define the s2m changes between Delta and SARS-CoV-2 and the subsequent impact of those changes upon the s2m dimerization and interactions with the host microRNA miR-1307-3p. Bioinformatics analysis of the GISAID database targeting the s2m element reveals a >99% correlation of a single nucleotide mutation at the 15th position (G15U) in Delta SARS-CoV-2. Based on 1H NMR spectroscopy assignments comparing the imino proton resonance region of s2m and the s2m G15U at 19°C, we show that the U15-A29 base pair closes, resulting in a stabilization of the upper stem without overall secondary structure deviation. Increased stability of the upper stem did not affect the chaperone activity of the viral N protein, as it was still able to convert the kissing dimers formed by s2m G15U into a stable duplex conformation, consistent with the s2m reference. However, we show that the s2m G15U mutation drastically impacts the binding of host miR-1307-3p. These findings demonstrate that the observed G15U mutation alters the secondary structure of s2m with subsequent impact on viral binding of host miR-1307-3p, with potential consequences on immune responses.
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Affiliation(s)
- Caylee L Cunningham
- Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, Pennsylvania 15282, USA
| | - Caleb J Frye
- Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, Pennsylvania 15282, USA
| | - Joseph A Makowski
- Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, Pennsylvania 15282, USA
| | - Adam H Kensinger
- Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, Pennsylvania 15282, USA
| | - Morgan Shine
- Department of Biochemistry and Chemistry, Westminster College, New Wilmington, Pennsylvania 16172, USA
| | - Ella J Milback
- Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, Pennsylvania 15282, USA
| | - Patrick E Lackey
- Department of Biochemistry and Chemistry, Westminster College, New Wilmington, Pennsylvania 16172, USA
| | - Jeffrey D Evanseck
- Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, Pennsylvania 15282, USA
| | - Mihaela-Rita Mihailescu
- Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, Pennsylvania 15282, USA
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3
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Chkuaseli T, White K. Dimerization of an umbravirus RNA genome activates subgenomic mRNA transcription. Nucleic Acids Res 2023; 51:8787-8804. [PMID: 37395397 PMCID: PMC10484742 DOI: 10.1093/nar/gkad550] [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: 05/31/2023] [Accepted: 06/16/2023] [Indexed: 07/04/2023] Open
Abstract
Many eukaryotic RNA viruses transcribe subgenomic (sg) mRNAs during infections to control expression of a subset of viral genes. Such transcriptional events are commonly regulated by local or long-range intragenomic interactions that form higher-order RNA structures within these viral genomes. In contrast, here we report that an umbravirus activates sg mRNA transcription via base pair-mediated dimerization of its plus-strand RNA genome. Compelling in vivo and in vitro evidence demonstrate that this viral genome dimerizes via a kissing-loop interaction involving an RNA stem-loop structure located just upstream from its transcriptional initiation site. Both specific and non-specific features of the palindromic kissing-loop complex were found to contribute to transcriptional activation. Structural and mechanistic aspects of the process in umbraviruses are discussed and compared with genome dimerization events in other RNA viruses. Notably, probable dimer-promoting RNA stem-loop structures were also identified in a diverse group of umbra-like viruses, suggesting broader utilization of this unconventional transcriptional strategy.
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Affiliation(s)
- Tamari Chkuaseli
- Department of Biology, York University, Toronto, Ontario M3J 1P3, Canada
| | - K Andrew White
- Department of Biology, York University, Toronto, Ontario M3J 1P3, Canada
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4
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Cunningham CL, Frye CJ, Makowski JA, Kensinger AH, Shine M, Milback EJ, Lackey PE, Evanseck JD, Mihailescu MR. Effect of the SARS-CoV-2 Delta-associated G15U mutation on the s2m element dimerization and its interactions with miR-1307-3p. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.10.528014. [PMID: 36798421 PMCID: PMC9934655 DOI: 10.1101/2023.02.10.528014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
The stem loop 2 motif (s2m), a highly conserved 41-nucleotide hairpin structure in the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) genome, serves as an attractive therapeutic target that may have important roles in the virus life cycle or interactions with the host. However, the conserved s2m in Delta SARS-CoV-2, a previously dominant variant characterized by high infectivity and disease severity, has received relatively less attention than that of the original SARS-CoV-2 virus. The focus of this work is to identify and define the s2m changes between Delta and SARS-CoV-2 and subsequent impact of those changes upon the s2m dimerization and interactions with the host microRNA miR-1307-3p. Bioinformatics analysis of the GISAID database targeting the s2m element reveals a greater than 99% correlation of a single nucleotide mutation at the 15 th position (G15U) in Delta SARS-CoV-2. Based on 1 H NMR assignments comparing the imino proton resonance region of s2m and the G15U at 19°C, we find that the U15-A29 base pair closes resulting in a stabilization of the upper stem without overall secondary structure deviation. Increased stability of the upper stem did not affect the chaperone activity of the viral N protein, as it was still able to convert the kissing dimers formed by s2m G15U into a stable duplex conformation, consistent with the s2m reference. However, we find that the s2m G15U mutation drastically reduces the binding affinity of the host miR-1307-3p. These findings demonstrate that the observed G15U mutation alters the secondary structure of s2m with subsequent impact on viral binding of host miR-1307-3p, with potential consequences on the immune response.
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5
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Chameettachal A, Mustafa F, Rizvi TA. Understanding Retroviral Life Cycle and its Genomic RNA Packaging. J Mol Biol 2023; 435:167924. [PMID: 36535429 DOI: 10.1016/j.jmb.2022.167924] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 12/12/2022] [Accepted: 12/12/2022] [Indexed: 12/23/2022]
Abstract
Members of the family Retroviridae are important animal and human pathogens. Being obligate parasites, their replication involves a series of steps during which the virus hijacks the cellular machinery. Additionally, many of the steps of retrovirus replication are unique among viruses, including reverse transcription, integration, and specific packaging of their genomic RNA (gRNA) as a dimer. Progress in retrovirology has helped identify several molecular mechanisms involved in each of these steps, but many are still unknown or remain controversial. This review summarizes our present understanding of the molecular mechanisms involved in various stages of retrovirus replication. Furthermore, it provides a comprehensive analysis of our current understanding of how different retroviruses package their gRNA into the assembling virions. RNA packaging in retroviruses holds a special interest because of the uniqueness of packaging a dimeric genome. Dimerization and packaging are highly regulated and interlinked events, critical for the virus to decide whether its unspliced RNA will be packaged as a "genome" or translated into proteins. Finally, some of the outstanding areas of exploration in the field of RNA packaging are highlighted, such as the role of epitranscriptomics, heterogeneity of transcript start sites, and the necessity of functional polyA sequences. An in-depth knowledge of mechanisms that interplay between viral and cellular factors during virus replication is critical in understanding not only the virus life cycle, but also its pathogenesis, and development of new antiretroviral compounds, vaccines, as well as retroviral-based vectors for human gene therapy.
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Affiliation(s)
- Akhil Chameettachal
- Department of Microbiology & Immunology, College of Medicine and Health Sciences (CMHS), United Arab Emirates University, Al Ain, United Arab Emirates. https://twitter.com/chameettachal
| | - Farah Mustafa
- Department of Biochemistry, College of Medicine and Health Sciences (CMHS), United Arab Emirates University, Al Ain, United Arab Emirates; Zayed bin Sultan Center for Health Sciences (ZCHS), United Arab Emirates University, Al Ain, United Arab Emirates.
| | - Tahir A Rizvi
- Department of Microbiology & Immunology, College of Medicine and Health Sciences (CMHS), United Arab Emirates University, Al Ain, United Arab Emirates; Zayed bin Sultan Center for Health Sciences (ZCHS), United Arab Emirates University, Al Ain, United Arab Emirates.
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6
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Chaminade F, Darlix JL, Fossé P. RNA Structural Requirements for Nucleocapsid Protein-Mediated Extended Dimer Formation. Viruses 2022; 14:606. [PMID: 35337013 PMCID: PMC8953772 DOI: 10.3390/v14030606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Revised: 03/09/2022] [Accepted: 03/11/2022] [Indexed: 11/16/2022] Open
Abstract
Retroviruses package two copies of their genomic RNA (gRNA) as non-covalently linked dimers. Many studies suggest that the retroviral nucleocapsid protein (NC) plays an important role in gRNA dimerization. The upper part of the L3 RNA stem-loop in the 5' leader of the avian leukosis virus (ALV) is converted to the extended dimer by ALV NC. The L3 hairpin contains three stems and two internal loops. To investigate the roles of internal loops and stems in the NC-mediated extended dimer formation, we performed site-directed mutagenesis, gel electrophoresis, and analysis of thermostability of dimeric RNAs. We showed that the internal loops are necessary for efficient extended dimer formation. Destabilization of the lower stem of L3 is necessary for RNA dimerization, although it is not involved in the linkage structure of the extended dimer. We found that NCs from ALV, human immunodeficiency virus type 1 (HIV-1), and Moloney murine leukemia virus (M-MuLV) cannot promote the formation of the extended dimer when the apical stem contains ten consecutive base pairs. Five base pairs correspond to the maximum length for efficient L3 dimerization induced by the three NCs. L3 dimerization was less efficient with M-MuLV NC than with ALV NC and HIV-1 NC.
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Affiliation(s)
- Françoise Chaminade
- LBPA, UMR8113 CNRS, ENS Paris-Saclay, Université Paris-Saclay, 91190 Gif-sur-Yvette, France;
| | - Jean-Luc Darlix
- Laboratoire de Bioimagerie et Pathologies, UMR7021 CNRS, Faculté de Pharmacie, Université de Strasbourg, 67400 Illkirch, France;
| | - Philippe Fossé
- LBPA, UMR8113 CNRS, ENS Paris-Saclay, Université Paris-Saclay, 91190 Gif-sur-Yvette, France;
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7
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Ye L, Gribling-Burrer AS, Bohn P, Kibe A, Börtlein C, Ambi UB, Ahmad S, Olguin-Nava M, Smith M, Caliskan N, von Kleist M, Smyth RP. Short- and long-range interactions in the HIV-1 5' UTR regulate genome dimerization and packaging. Nat Struct Mol Biol 2022; 29:306-319. [PMID: 35347312 PMCID: PMC9010304 DOI: 10.1038/s41594-022-00746-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 02/14/2022] [Indexed: 11/09/2022]
Abstract
RNA dimerization is the noncovalent association of two human immunodeficiency virus-1 (HIV-1) genomes. It is a conserved step in the HIV-1 life cycle and assumed to be a prerequisite for binding to the viral structural protein Pr55Gag during genome packaging. Here, we developed functional analysis of RNA structure-sequencing (FARS-seq) to comprehensively identify sequences and structures within the HIV-1 5' untranslated region (UTR) that regulate this critical step. Using FARS-seq, we found nucleotides important for dimerization throughout the HIV-1 5' UTR and identified distinct structural conformations in monomeric and dimeric RNA. In the dimeric RNA, key functional domains, such as stem-loop 1 (SL1), polyadenylation signal (polyA) and primer binding site (PBS), folded into independent structural motifs. In the monomeric RNA, SL1 was reconfigured into long- and short-range base pairings with polyA and PBS, respectively. We show that these interactions disrupt genome packaging, and additionally show that the PBS-SL1 interaction unexpectedly couples the PBS with dimerization and Pr55Gag binding. Altogether, our data provide insights into late stages of HIV-1 life cycle and a mechanistic explanation for the link between RNA dimerization and packaging.
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Affiliation(s)
- Liqing Ye
- grid.498164.6Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, Würzburg, Germany
| | - Anne-Sophie Gribling-Burrer
- grid.498164.6Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, Würzburg, Germany
| | - Patrick Bohn
- grid.498164.6Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, Würzburg, Germany
| | - Anuja Kibe
- grid.498164.6Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, Würzburg, Germany
| | - Charlene Börtlein
- grid.498164.6Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, Würzburg, Germany
| | - Uddhav B. Ambi
- grid.498164.6Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, Würzburg, Germany
| | - Shazeb Ahmad
- grid.498164.6Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, Würzburg, Germany
| | - Marco Olguin-Nava
- grid.498164.6Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, Würzburg, Germany
| | - Maureen Smith
- grid.13652.330000 0001 0940 3744P5 Systems Medicine of Infectious Disease, Robert Koch-Institute, Berlin, Germany
| | - Neva Caliskan
- grid.498164.6Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, Würzburg, Germany ,grid.8379.50000 0001 1958 8658Faculty of Medicine, University of Würzburg, Würzburg, Germany
| | - Max von Kleist
- grid.13652.330000 0001 0940 3744P5 Systems Medicine of Infectious Disease, Robert Koch-Institute, Berlin, Germany
| | - Redmond P. Smyth
- grid.498164.6Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, Würzburg, Germany ,grid.8379.50000 0001 1958 8658Faculty of Medicine, University of Würzburg, Würzburg, Germany
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8
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Imperatore JA, Cunningham CL, Pellegrene KA, Brinson R, Marino J, Evanseck J, Mihailescu M. Highly conserved s2m element of SARS-CoV-2 dimerizes via a kissing complex and interacts with host miRNA-1307-3p. Nucleic Acids Res 2021; 50:1017-1032. [PMID: 34908151 PMCID: PMC8789046 DOI: 10.1093/nar/gkab1226] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 11/26/2021] [Accepted: 12/01/2021] [Indexed: 01/14/2023] Open
Abstract
The ongoing COVID-19 pandemic highlights the necessity for a more fundamental understanding of the coronavirus life cycle. The causative agent of the disease, SARS-CoV-2, is being studied extensively from a structural standpoint in order to gain insight into key molecular mechanisms required for its survival. Contained within the untranslated regions of the SARS-CoV-2 genome are various conserved stem-loop elements that are believed to function in RNA replication, viral protein translation, and discontinuous transcription. While the majority of these regions are variable in sequence, a 41-nucleotide s2m element within the genome 3' untranslated region is highly conserved among coronaviruses and three other viral families. In this study, we demonstrate that the SARS-CoV-2 s2m element dimerizes by forming an intermediate homodimeric kissing complex structure that is subsequently converted to a thermodynamically stable duplex conformation. This process is aided by the viral nucleocapsid protein, potentially indicating a role in mediating genome dimerization. Furthermore, we demonstrate that the s2m element interacts with multiple copies of host cellular microRNA (miRNA) 1307-3p. Taken together, our results highlight the potential significance of the dimer structures formed by the s2m element in key biological processes and implicate the motif as a possible therapeutic drug target for COVID-19 and other coronavirus-related diseases.
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Affiliation(s)
- Joshua A Imperatore
- Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, PA 15282, USA
| | - Caylee L Cunningham
- Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, PA 15282, USA
| | - Kendy A Pellegrene
- Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, PA 15282, USA
| | - Robert G Brinson
- Institute for Bioscience and Biotechnology Research, National Institute of Standards and Technology and the University of Maryland, Rockville, MD 20850, USA
| | - John P Marino
- Institute for Bioscience and Biotechnology Research, National Institute of Standards and Technology and the University of Maryland, Rockville, MD 20850, USA
| | - Jeffrey D Evanseck
- Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, PA 15282, USA
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9
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Blakemore RJ, Burnett C, Swanson C, Kharytonchyk S, Telesnitsky A, Munro JB. Stability and conformation of the dimeric HIV-1 genomic RNA 5'UTR. Biophys J 2021; 120:4874-4890. [PMID: 34529947 PMCID: PMC8595565 DOI: 10.1016/j.bpj.2021.09.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 08/13/2021] [Accepted: 09/08/2021] [Indexed: 12/20/2022] Open
Abstract
During HIV-1 assembly, the viral Gag polyprotein specifically selects the dimeric RNA genome for packaging into new virions. The 5′ untranslated region (5′UTR) of the dimeric genome may adopt a conformation that is optimal for recognition by Gag. Further conformational rearrangement of the 5′UTR, promoted by the nucleocapsid (NC) domain of Gag, is predicted during virus maturation. Two 5′UTR dimer conformations, the kissing dimer (KD) and the extended dimer (ED), have been identified in vitro, which differ in the extent of intermolecular basepairing. Whether 5′UTRs from different HIV-1 strains with distinct sequences have access to the same dimer conformations has not been determined. Here, we applied fluorescence cross-correlation spectroscopy and single-molecule Förster resonance energy transfer imaging to demonstrate that 5′UTRs from two different HIV-1 subtypes form (KDs) with divergent stabilities. We further show that both 5′UTRs convert to a stable dimer in the presence of the viral NC protein, adopting a conformation consistent with extensive intermolecular contacts. These results support a unified model in which the genomes of diverse HIV-1 strains adopt an ED conformation.
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Affiliation(s)
- Robert J Blakemore
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine and School of Graduate Biomedical Sciences, Boston, Massachusetts; Graduate Program in Molecular Microbiology, Tufts University Graduate School of Biomedical Sciences, Boston, Massachusetts
| | - Cleo Burnett
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan
| | - Canessa Swanson
- Department of Chemistry and Biochemistry, University of Maryland Baltimore Country, Baltimore, Maryland
| | - Siarhei Kharytonchyk
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan
| | - Alice Telesnitsky
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan
| | - James B Munro
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine and School of Graduate Biomedical Sciences, Boston, Massachusetts; Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, Massachusetts; Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts.
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10
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Chen EC, Maldonado RJK, Parent LJ. Visualizing Rous Sarcoma Virus Genomic RNA Dimerization in the Nucleus, Cytoplasm, and at the Plasma Membrane. Viruses 2021; 13:v13050903. [PMID: 34068261 PMCID: PMC8153106 DOI: 10.3390/v13050903] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 04/30/2021] [Accepted: 05/07/2021] [Indexed: 01/01/2023] Open
Abstract
Retroviruses are unique in that they package their RNA genomes as non-covalently linked dimers. Failure to dimerize their genomes results in decreased infectivity and reduced packaging of genomic RNA into virus particles. Two models of retrovirus genome dimerization have been characterized: in murine leukemia virus (MLV), genomic RNA dimerization occurs co-transcriptionally in the nucleus, resulting in the preferential formation of genome homodimers; whereas in human immunodeficiency virus (HIV-1), genomic RNA dimerization occurs in the cytoplasm and at the plasma membrane, with a random distribution of heterodimers and homodimers. Although in vitro studies have identified the genomic RNA sequences that facilitate dimerization in Rous sarcoma virus (RSV), in vivo characterization of the location and preferences of genome dimerization has not been performed. In this study, we utilized three single molecule RNA imaging approaches to visualize genome dimers of RSV in cultured quail fibroblasts. The formation of genomic RNA heterodimers within cells was dependent on the presence of the dimerization initiation site (DIS) sequence in the L3 stem. Subcellular localization analysis revealed that heterodimers were present the nucleus, cytoplasm, and at the plasma membrane, indicating that genome dimers can form in the nucleus. Furthermore, single virion analysis revealed that RSV preferentially packages genome homodimers into virus particles. Therefore, the mechanism of RSV genomic RNA dimer formation appears more similar to MLV than HIV-1.
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Affiliation(s)
- Eunice C. Chen
- Department of Medicine, Division of Infectious Diseases and Epidemiology, Penn State College of Medicine, Hershey, PA 17033, USA; (E.C.C.); (R.J.K.M.)
| | - Rebecca J. Kaddis Maldonado
- Department of Medicine, Division of Infectious Diseases and Epidemiology, Penn State College of Medicine, Hershey, PA 17033, USA; (E.C.C.); (R.J.K.M.)
| | - Leslie J. Parent
- Department of Medicine, Division of Infectious Diseases and Epidemiology, Penn State College of Medicine, Hershey, PA 17033, USA; (E.C.C.); (R.J.K.M.)
- Department of Microbiology & Immunology, Penn State College of Medicine, Hershey, PA 17033, USA
- Correspondence: ; Tel.: +1-717-531-7199
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11
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Boyd PS, Brown JB, Brown JD, Catazaro J, Chaudry I, Ding P, Dong X, Marchant J, O’Hern CT, Singh K, Swanson C, Summers MF, Yasin S. NMR Studies of Retroviral Genome Packaging. Viruses 2020; 12:v12101115. [PMID: 33008123 PMCID: PMC7599994 DOI: 10.3390/v12101115] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 09/18/2020] [Accepted: 09/26/2020] [Indexed: 12/03/2022] Open
Abstract
Nearly all retroviruses selectively package two copies of their unspliced RNA genomes from a cellular milieu that contains a substantial excess of non-viral and spliced viral RNAs. Over the past four decades, combinations of genetic experiments, phylogenetic analyses, nucleotide accessibility mapping, in silico RNA structure predictions, and biophysical experiments were employed to understand how retroviral genomes are selected for packaging. Genetic studies provided early clues regarding the protein and RNA elements required for packaging, and nucleotide accessibility mapping experiments provided insights into the secondary structures of functionally important elements in the genome. Three-dimensional structural determinants of packaging were primarily derived by nuclear magnetic resonance (NMR) spectroscopy. A key advantage of NMR, relative to other methods for determining biomolecular structure (such as X-ray crystallography), is that it is well suited for studies of conformationally dynamic and heterogeneous systems—a hallmark of the retrovirus packaging machinery. Here, we review advances in understanding of the structures, dynamics, and interactions of the proteins and RNA elements involved in retroviral genome selection and packaging that are facilitated by NMR.
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12
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Wolff P, Ennifar E. Native Electrospray Ionization Mass Spectrometry of RNA-Ligand Complexes. Methods Mol Biol 2020; 2113:111-118. [PMID: 32006311 DOI: 10.1007/978-1-0716-0278-2_9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Native electrospray ionization mass spectrometry (native ESI-MS) is a powerful tool to investigate non-covalent biomolecular interactions. It has been widely used to study protein complexes, but only few examples are described for the analysis of complexes involving RNA-RNA interactions. Here, we provide a detailed protocol for native ESI-MS analysis of RNA complexes. As an example, we present the analysis of the HIV-1 genomic RNA dimerization initiation site (DIS) extended duplex dimer bound to the aminoglycoside antibiotic lividomycin.
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Affiliation(s)
- Philippe Wolff
- Architecture et Réactivité de l'ARN - CNRS UPR 9002, Institut de Biologie Moléculaire et Cellulaire, Université de Strasbourg, Strasbourg, France. .,Plateforme protéomique Strasbourg Esplanade, FRC1589 du CNRS, Université de Strasbourg, Strasbourg, France.
| | - Eric Ennifar
- Architecture et Réactivité de l'ARN - CNRS UPR 9002, Institut de Biologie Moléculaire et Cellulaire, Université de Strasbourg, Strasbourg, France
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13
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Wojciechowska M, Dudek M, Trylska J. Thermodynamics of the pseudo-knot in helix 18 of 16S ribosomal RNA. Biopolymers 2018; 109:e23116. [PMID: 29570767 DOI: 10.1002/bip.23116] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 02/24/2018] [Accepted: 02/27/2018] [Indexed: 01/13/2023]
Abstract
A fragment of E. coli 16S rRNA formed by nucleotides 500 to 545 is termed helix 18. Nucleotides 505-507 and 524-526 form a pseudo-knot and its distortion affects ribosome function. Helix 18 isolated from the ribosome context is thus an interesting fragment to investigate the structural properties and folding of RNA with pseudo-knots. With all-atom molecular dynamics simulations, spectroscopic and gel electrophoresis experiments, we investigated thermodynamics of helix 18, with a focus on its pseudo-knot. In solution studies at ambient conditions we observed dimerization of helix 18. We proposed that the loop, containing nucleotides forming the pseudo-knot, interacts with another monomer of helix 18. The native dimer is difficult to break but introducing mutations in the pseudo-knot indeed assured a monomeric form of helix 18. Molecular dynamics simulations at 310 K confirmed the stability of the pseudo-knot but at elevated temperatures this pseudo-knot was the first part of helix 18 to lose the hydrogen bond pattern. To further determine helix 18 stability, we analyzed the interactions of helix 18 with short oligomers complementary to a nucleotide stretch containing the pseudo-knot. The formation of higher-order structures by helix 18 impacts hybridization efficiency of peptide nucleic acid and 2'-O methyl RNA oligomers.
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Affiliation(s)
- Monika Wojciechowska
- Centre of New Technologies, University of Warsaw, Banacha 2C, Warsaw, 02-09, Poland
| | - Marta Dudek
- Centre of New Technologies, University of Warsaw, Banacha 2C, Warsaw, 02-09, Poland.,School of Molecular Biology, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, Warsaw, 02-106, Poland.,First Faculty of Medicine, Department of Hematology, Oncology and Internal Diseases, Medical University of Warsaw, Al. Żwirki i Wigury 61, Warsaw, 02-091, Poland
| | - Joanna Trylska
- Centre of New Technologies, University of Warsaw, Banacha 2C, Warsaw, 02-09, Poland
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14
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Dubois N, Marquet R, Paillart JC, Bernacchi S. Retroviral RNA Dimerization: From Structure to Functions. Front Microbiol 2018; 9:527. [PMID: 29623074 PMCID: PMC5874298 DOI: 10.3389/fmicb.2018.00527] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Accepted: 03/08/2018] [Indexed: 01/18/2023] Open
Abstract
The genome of the retroviruses is a dimer composed by two homologous copies of genomic RNA (gRNA) molecules of positive polarity. The dimerization process allows two gRNA molecules to be non-covalently linked together through intermolecular base-pairing. This step is critical for the viral life cycle and is highly conserved among retroviruses with the exception of spumaretroviruses. Furthermore, packaging of two gRNA copies into viral particles presents an important evolutionary advantage for immune system evasion and drug resistance. Recent studies reported RNA switches models regulating not only gRNA dimerization, but also translation and packaging, and a spatio-temporal characterization of viral gRNA dimerization within cells are now at hand. This review summarizes our current understanding on the structural features of the dimerization signals for a variety of retroviruses (HIVs, MLV, RSV, BLV, MMTV, MPMV…), the mechanisms of RNA dimer formation and functional implications in the retroviral cycle.
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Affiliation(s)
- Noé Dubois
- Architecture et Réactivité de l'ARN, UPR 9002, IBMC, CNRS, Université de Strasbourg, Strasbourg, France
| | - Roland Marquet
- Architecture et Réactivité de l'ARN, UPR 9002, IBMC, CNRS, Université de Strasbourg, Strasbourg, France
| | - Jean-Christophe Paillart
- Architecture et Réactivité de l'ARN, UPR 9002, IBMC, CNRS, Université de Strasbourg, Strasbourg, France
| | - Serena Bernacchi
- Architecture et Réactivité de l'ARN, UPR 9002, IBMC, CNRS, Université de Strasbourg, Strasbourg, France
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15
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Bernacchi S, Abd El-Wahab EW, Dubois N, Hijnen M, Smyth RP, Mak J, Marquet R, Paillart JC. HIV-1 Pr55 Gag binds genomic and spliced RNAs with different affinity and stoichiometry. RNA Biol 2016; 14:90-103. [PMID: 27841704 DOI: 10.1080/15476286.2016.1256533] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
The HIV-1 Pr55Gag precursor specifically selects genomic RNA (gRNA) from a large variety of cellular and spliced viral RNAs (svRNAs), however the molecular mechanisms of this selective recognition remains poorly understood. To gain better understanding of this process, we analyzed the interactions between Pr55Gag and a large panel of viral RNA (vRNA) fragments encompassing the main packaging signal (Psi) and its flanking regions by fluorescence spectroscopy. We showed that the gRNA harbors a high affinity binding site which is absent from svRNA species, suggesting that this site might be crucial for selecting the HIV-1 genome. Our stoichiometry analysis of protein/RNA complexes revealed that few copies of Pr55Gag specifically associate with the 5' region of the gRNA. Besides, we found that gRNA dimerization significantly impacts Pr55Gag binding, and we confirmed that the internal loop of stem-loop 1 (SL1) in Psi is crucial for specific interaction with Pr55Gag. Our analysis of gRNA fragments of different length supports the existence of a long-range tertiary interaction involving sequences upstream and downstream of the Psi region. This long-range interaction might promote optimal exposure of SL1 for efficient Pr55Gag recognition. Altogether, our results shed light on the molecular mechanisms allowing the specific selection of gRNA by Pr55Gag among a variety of svRNAs, all harboring SL1 in their first common exon.
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Affiliation(s)
- Serena Bernacchi
- a Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN , Strasbourg , France
| | - Ekram W Abd El-Wahab
- a Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN , Strasbourg , France
| | - Noé Dubois
- a Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN , Strasbourg , France
| | - Marcel Hijnen
- b Centre for Virology, Burnet Institute , Melbourne , Victoria , Australia.,c Department of Biochemistry and Molecular Biology , Monash University , Clayton , Victoria , Australia
| | - Redmond P Smyth
- a Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN , Strasbourg , France
| | - Johnson Mak
- b Centre for Virology, Burnet Institute , Melbourne , Victoria , Australia.,c Department of Biochemistry and Molecular Biology , Monash University , Clayton , Victoria , Australia.,d School of Medicine, Faculty of Health, Deakin University , Geelong , Victoria , Australia.,e Commonwealth Scientific and Industrial Research Organization, Livestock Industries, Australian Animal Health Laboratory , Geelong , Victoria , Australia
| | - Roland Marquet
- a Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN , Strasbourg , France
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16
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17
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NMR detection of intermolecular interaction sites in the dimeric 5'-leader of the HIV-1 genome. Proc Natl Acad Sci U S A 2016; 113:13033-13038. [PMID: 27791166 DOI: 10.1073/pnas.1614785113] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
HIV type-1 (HIV-1) contains a pseudodiploid RNA genome that is selected for packaging and maintained in virions as a noncovalently linked dimer. Genome dimerization is mediated by conserved elements within the 5'-leader of the RNA, including a palindromic dimer initiation signal (DIS) that has been proposed to form kissing hairpin and/or extended duplex intermolecular contacts. Here, we have applied a 2H-edited NMR approach to directly probe for intermolecular interactions in the full-length, dimeric HIV-1 5'-leader (688 nucleotides; 230 kDa). The interface is extensive and includes DIS:DIS base pairing in an extended duplex state as well as intermolecular pairing between elements of the upstream Unique-5' (U5) sequence and those near the gag start site (AUG). Other pseudopalindromic regions of the leader, including the transcription activation (TAR), polyadenylation (PolyA), and primer binding (PBS) elements, do not participate in intermolecular base pairing. Using a 2H-edited one-dimensional NMR approach, we also show that the extended interface structure forms on a time scale similar to that of overall RNA dimerization. Our studies indicate that a kissing dimer-mediated structure, if formed, exists only transiently and readily converts to the extended interface structure, even in the absence of the HIV-1 nucleocapsid protein or other RNA chaperones.
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18
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Abstract
RNA/RNA interactions are essential for genomic RNA dimerization and regulation of gene expression. Intermolecular loop-loop base pairing is a widespread and functionally important tertiary structure motif in RNA machinery. However, computational prediction of intermolecular loop-loop base pairing is challenged by the entropy and free energy calculation due to the conformational constraint and the intermolecular interactions. In this chapter, we describe a recently developed statistical mechanics-based method for the prediction of RNA/RNA complex structures and stabilities. The method is based on the virtual bond RNA folding model (Vfold). The main emphasis in the method is placed on the evaluation of the entropy and free energy for the loops, especially tertiary kissing loops. The method also uses recursive partition function calculations and two-step screening algorithm for large, complicated structures of RNA/RNA complexes. As case studies, we use the HIV-1 Mal dimer and the siRNA/HIV-1 mutant (T4) to illustrate the method.
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Affiliation(s)
- Xiaojun Xu
- Department of Physics, Informatics Institute, University of Missouri, Columbia, MI, USA.,Department of Biochemistry, Informatics Institute, University of Missouri, Columbia, MI, USA.,Center for RNA Biology, University of Rochester Medical Center, Rochester, NY, USA
| | - Shi-Jie Chen
- Department of Physics, Informatics Institute, University of Missouri, Columbia, MI, USA.,Department of Biochemistry, Informatics Institute, University of Missouri, Columbia, MI, USA.,Center for RNA Biology, University of Rochester Medical Center, Rochester, NY, USA
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HIV-1 RNA genome dimerizes on the plasma membrane in the presence of Gag protein. Proc Natl Acad Sci U S A 2015; 113:E201-8. [PMID: 26712001 DOI: 10.1073/pnas.1518572113] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Retroviruses package a dimeric genome comprising two copies of the viral RNA. Each RNA contains all of the genetic information for viral replication. Packaging a dimeric genome allows the recovery of genetic information from damaged RNA genomes during DNA synthesis and promotes frequent recombination to increase diversity in the viral population. Therefore, the strategy of packaging dimeric RNA affects viral replication and viral evolution. Although its biological importance is appreciated, very little is known about the genome dimerization process. HIV-1 RNA genomes dimerize before packaging into virions, and RNA interacts with the viral structural protein Gag in the cytoplasm. Thus, it is often hypothesized that RNAs dimerize in the cytoplasm and the RNA-Gag complex is transported to the plasma membrane for virus assembly. In this report, we tagged HIV-1 RNAs with fluorescent proteins, via interactions of RNA-binding proteins and motifs in the RNA genomes, and studied their behavior at the plasma membrane by using total internal reflection fluorescence microscopy. We showed that HIV-1 RNAs dimerize not in the cytoplasm but on the plasma membrane. Dynamic interactions occur among HIV-1 RNAs, and stabilization of the RNA dimer requires Gag protein. Dimerization often occurs at an early stage of the virus assembly process. Furthermore, the dimerization process is probably mediated by the interactions of two RNA-Gag complexes, rather than two RNAs. These findings advance the current understanding of HIV-1 assembly and reveal important insights into viral replication mechanisms.
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20
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Tran T, Liu Y, Marchant J, Monti S, Seu M, Zaki J, Yang AL, Bohn J, Ramakrishnan V, Singh R, Hernandez M, Vega A, Summers MF. Conserved determinants of lentiviral genome dimerization. Retrovirology 2015; 12:83. [PMID: 26420212 PMCID: PMC4588261 DOI: 10.1186/s12977-015-0209-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 09/18/2015] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND Retroviruses selectively package two copies of their unspliced genomes by what appears to be a dimerization-dependent RNA packaging mechanism. Dimerization of human immunodeficiency virus Type-1 (HIV-1) genomes is initiated by "kissing" interactions between GC-rich palindromic loop residues of a conserved hairpin (DIS), and is indirectly promoted by long-range base pairing between residues overlapping the gag start codon (AUG) and an upstream Unique 5' element (U5). The DIS and U5:AUG structures are phylogenetically conserved among divergent retroviruses, suggesting conserved functions. However, some studies suggest that the DIS of HIV-2 does not participate in dimerization, and that U5:AUG pairing inhibits, rather than promotes, genome dimerization. We prepared RNAs corresponding to native and mutant forms of the 5' leaders of HIV-1 (NL4-3 strain), HIV-2 (ROD strain), and two divergent strains of simian immunodeficiency virus (SIV; cpz-TAN1 and -US strains), and probed for potential roles of the DIS and U5:AUG base pairing on intrinsic and NC-dependent dimerization by mutagenesis, gel electrophoresis, and NMR spectroscopy. RESULTS Dimeric forms of the native HIV-2 and SIV leaders were only detectable using running buffers that contained Mg(2+), indicating that these dimers are more labile than that of the HIV-1 leader. Mutations designed to promote U5:AUG base pairing promoted dimerization of the HIV-2 and SIV RNAs, whereas mutations that prevented U5:AUG pairing inhibited dimerization. Chimeric HIV-2 and SIV leader RNAs containing the dimer-promoting loop of HIV-1 (DIS) exhibited HIV-1 leader-like dimerization properties, whereas an HIV-1NL4-3 mutant containing the SIVcpzTAN1 DIS loop behaved like the SIVcpzTAN1 leader. The cognate NC proteins exhibited varying abilities to promote dimerization of the retroviral leader RNAs, but none were able to convert labile dimers to non-labile dimers. CONCLUSIONS The finding that U5:AUG formation promotes dimerization of the full-length HIV-1, HIV-2, SIVcpzUS, and SIVcpzTAN1 5' leaders suggests that these retroviruses utilize a common RNA structural switch mechanism to modulate function. Differences in native and NC-dependent dimerization propensity and lability are due to variations in the compositions of the DIS loop residues rather than other sequences within the leader RNAs. Although NC is a well-known RNA chaperone, its role in dimerization has the hallmarks of a classical riboswitch.
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Affiliation(s)
- Thao Tran
- Howard Hughes Medical Institute, Department of Chemistry and Biochemistry, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD, 21250, USA.
| | - Yuanyuan Liu
- Howard Hughes Medical Institute, Department of Chemistry and Biochemistry, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD, 21250, USA.
| | - Jan Marchant
- Howard Hughes Medical Institute, Department of Chemistry and Biochemistry, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD, 21250, USA.
| | - Sarah Monti
- Howard Hughes Medical Institute, Department of Chemistry and Biochemistry, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD, 21250, USA.
| | - Michelle Seu
- Howard Hughes Medical Institute, Department of Chemistry and Biochemistry, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD, 21250, USA.
| | - Jessica Zaki
- Howard Hughes Medical Institute, Department of Chemistry and Biochemistry, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD, 21250, USA.
| | - Ae Lim Yang
- Howard Hughes Medical Institute, Department of Chemistry and Biochemistry, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD, 21250, USA.
| | - Jennifer Bohn
- Howard Hughes Medical Institute, Department of Chemistry and Biochemistry, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD, 21250, USA.
| | - Venkateswaran Ramakrishnan
- Howard Hughes Medical Institute, Department of Chemistry and Biochemistry, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD, 21250, USA.
| | - Rashmi Singh
- Howard Hughes Medical Institute, Department of Chemistry and Biochemistry, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD, 21250, USA.
| | - Mateo Hernandez
- Howard Hughes Medical Institute, Department of Chemistry and Biochemistry, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD, 21250, USA.
| | - Alexander Vega
- Howard Hughes Medical Institute, Department of Chemistry and Biochemistry, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD, 21250, USA.
| | - Michael F Summers
- Howard Hughes Medical Institute, Department of Chemistry and Biochemistry, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD, 21250, USA.
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21
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van Bel N, Ghabri A, Das AT, Berkhout B. The HIV-1 leader RNA is exquisitely sensitive to structural changes. Virology 2015; 483:236-52. [DOI: 10.1016/j.virol.2015.03.050] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2014] [Revised: 03/05/2015] [Accepted: 03/27/2015] [Indexed: 01/14/2023]
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22
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Abstract
Despite the success of RNA secondary structure prediction for simple, short RNAs, the problem of predicting RNAs with long-range tertiary folds remains. Furthermore, RNA 3D structure prediction is hampered by the lack of the knowledge about the tertiary contacts and their thermodynamic parameters. Low-resolution structural modeling enables us to estimate the conformational entropies for a number of tertiary folds through rigorous statistical mechanical calculations. The models lead to 3D tertiary folds at coarse-grained level. The coarse-grained structures serve as the initial structures for all-atom molecular dynamics refinement to build the final all-atom 3D structures. In this paper, we present an overview of RNA computational models for secondary and tertiary structures’ predictions and then focus on a recently developed RNA statistical mechanical model—the Vfold model. The main emphasis is placed on the physics behind the models, including the treatment of the non-canonical interactions in secondary and tertiary structure modelings, and the correlations to RNA functions.
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Affiliation(s)
- Xiaojun Xu
- />Department of Physics, University of Missouri, Columbia, MO 65211 USA
- />Department of Biochemistry, University of Missouri, Columbia, MO 65211 USA
- />Informatics Institute, University of Missouri, Columbia, MO 65211 USA
| | - Shi-Jie Chen
- />Department of Physics, University of Missouri, Columbia, MO 65211 USA
- />Department of Biochemistry, University of Missouri, Columbia, MO 65211 USA
- />Informatics Institute, University of Missouri, Columbia, MO 65211 USA
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23
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Blond A, Ennifar E, Tisné C, Micouin L. The design of RNA binders: targeting the HIV replication cycle as a case study. ChemMedChem 2014; 9:1982-96. [PMID: 25100137 DOI: 10.1002/cmdc.201402259] [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: 06/23/2014] [Indexed: 01/08/2023]
Abstract
The human immunodeficiency virus 1 (HIV-1) replication cycle is finely tuned with many important steps involving RNA-RNA or protein-RNA interactions, all of them being potential targets for the development of new antiviral compounds. This cycle can also be considered as a good benchmark for the evaluation of early-stage strategies aiming at designing drugs that bind to RNA, with the possibility to correlate in vitro activities with antiviral properties. In this review, we highlight different approaches developed to interfere with four important steps of the HIV-1 replication cycle: the early stage of reverse transcription, the transactivation of viral transcription, the nuclear export of partially spliced transcripts and the dimerization step.
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Affiliation(s)
- Aurélie Blond
- Laboratoire de Chimie et Biochimie Pharmacologiques et Toxicologiques, UMR 8601, CNRS, Université Paris Descartes, Sorbonne Paris Cité, Faculté des Sciences Fondamentales et Biomédicales, 45 Rue des Saints Pères, 75006 Paris (France)
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24
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van Bel N, van der Velden Y, Bonnard D, Le Rouzic E, Das AT, Benarous R, Berkhout B. The allosteric HIV-1 integrase inhibitor BI-D affects virion maturation but does not influence packaging of a functional RNA genome. PLoS One 2014; 9:e103552. [PMID: 25072705 PMCID: PMC4114784 DOI: 10.1371/journal.pone.0103552] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Accepted: 05/20/2014] [Indexed: 12/30/2022] Open
Abstract
The viral integrase (IN) is an essential protein for HIV-1 replication. IN inserts the viral dsDNA into the host chromosome, thereby aided by the cellular co-factor LEDGF/p75. Recently a new class of integrase inhibitors was described: allosteric IN inhibitors (ALLINIs). Although designed to interfere with the IN-LEDGF/p75 interaction to block HIV DNA integration during the early phase of HIV-1 replication, the major impact was surprisingly found on the process of virus maturation during the late phase, causing a reverse transcription defect upon infection of target cells. Virus particles produced in the presence of an ALLINI are misformed with the ribonucleoprotein located outside the virus core. Virus assembly and maturation are highly orchestrated and regulated processes in which several viral proteins and RNA molecules closely interact. It is therefore of interest to study whether ALLINIs have unpredicted pleiotropic effects on these RNA-related processes. We confirm that the ALLINI BI-D inhibits virus replication and that the produced virus is non-infectious. Furthermore, we show that the wild-type level of HIV-1 genomic RNA is packaged in virions and these genomes are in a dimeric state. The tRNAlys3 primer for reverse transcription was properly placed on this genomic RNA and could be extended ex vivo. In addition, the packaged reverse transcriptase enzyme was fully active when extracted from virions. As the RNA and enzyme components for reverse transcription are properly present in virions produced in the presence of BI-D, the inhibition of reverse transcription is likely to reflect the mislocalization of the components in the aberrant virus particle.
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Affiliation(s)
- Nikki van Bel
- Laboratory of Experimental Virology, Department of Medical Microbiology, Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands
| | - Yme van der Velden
- Laboratory of Experimental Virology, Department of Medical Microbiology, Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands
| | | | | | - Atze T. Das
- Laboratory of Experimental Virology, Department of Medical Microbiology, Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands
| | | | - Ben Berkhout
- Laboratory of Experimental Virology, Department of Medical Microbiology, Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands
- * E-mail:
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25
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Mundigala H, Michaux JB, Feig AL, Ennifar E, Rueda D. HIV-1 DIS stem loop forms an obligatory bent kissing intermediate in the dimerization pathway. Nucleic Acids Res 2014; 42:7281-9. [PMID: 24813449 PMCID: PMC4066764 DOI: 10.1093/nar/gku332] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The HIV-1 dimerization initiation sequence (DIS) is a conserved palindrome in the apical loop of a conserved hairpin motif in the 5′-untranslated region of its RNA genome. DIS hairpin plays an important role in genome dimerization by forming a ‘kissing complex’ between two complementary hairpins. Understanding the kinetics of this interaction is key to exploiting DIS as a possible human immunodeficiency virus (HIV) drug target. Here, we present a single-molecule Förster resonance energy transfer (smFRET) study of the dimerization reaction kinetics. Our data show the real-time formation and dissociation dynamics of individual kissing complexes, as well as the formation of the mature extended duplex complex that is ultimately required for virion packaging. Interestingly, the single-molecule trajectories reveal the presence of a previously unobserved bent intermediate required for extended duplex formation. The universally conserved A272 is essential for the formation of this intermediate, which is stabilized by Mg2+, but not by K+ cations. We propose a 3D model of a possible bent intermediate and a minimal dimerization pathway consisting of three steps with two obligatory intermediates (kissing complex and bent intermediate) and driven by Mg2+ ions.
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Affiliation(s)
- Hansini Mundigala
- Department of Chemistry, Wayne State University, Detroit, MI 48236, USA
| | | | - Andrew L Feig
- Department of Chemistry, Wayne State University, Detroit, MI 48236, USA
| | - Eric Ennifar
- Architecture et Réactivité de l'ARN, Université de Strasbourg, Institut de Biologie Moléculaire et Cellulaire du CNRS, F-67084 Strasbourg, France
| | - David Rueda
- Department of Chemistry, Wayne State University, Detroit, MI 48236, USA Department of Medicine, Section of Virology, Imperial College, London W12 0NN, UK Single Molecule Imaging Group, MRC Clinical Sciences Center, Imperial College, London W12 0NN, UK
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26
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Abstract
The 5' untranslated leader region of the human immunodeficiency virus type 1 (HIV-1) RNA genome is a strongly conserved sequence that encodes several regulatory motifs important for viral replication. Most of these motifs are exposed as hairpin structures, including the dimerization initiation signal (DIS), the major splice donor site (SD), and the packaging signal (Ψ), which are connected by short single-stranded regions. Mutational analysis revealed many functions of these hairpins, but only a few studies have focused on the single-stranded purine-rich sequences. Using the in vivo SELEX (systematic evolution of ligands by exponential enrichment) approach, we probed the sequence space in these regions that is compatible with efficient HIV-1 replication and analyzed the impact on the RNA secondary structure of the leader RNA. Our results show a strong sequence requirement for the DIS hairpin flanking regions. We postulate that these sequences are important for the binding of specific protein factors that support leader RNA-mediated functions. The sequence between the SD and Ψ hairpins seems to have a less prominent role, despite the strong conservation of the stretch of 5 A residues in natural isolates. We hypothesize that this may reflect the subtle evolutionary pressure on HIV-1 to acquire an A-rich RNA genome. In silico analyses indicate that sequences are avoided in all 3 single-stranded domains that affect the local or overall leader RNA folding. IMPORTANCE Many regulatory RNA sequences are clustered in the untranslated leader domain of the HIV-1 RNA genome. Several RNA hairpin structures in this domain have been proposed to fulfill specific roles, e.g., mediating RNA dimer formation to facilitate HIV-1 recombination. We now focus on the importance of a few well-conserved single-stranded sequences that connect these hairpins. We created libraries of HIV-1 variants in which these segments were randomized and selected the best-replicating variants. For two segments we document the selection of the (nearly) wild-type sequence, thus demonstrating the importance of these primary nucleotide sequences and the power of the in vivo SELEX approach. However, for the third segment a large variety of sequences is compatible with efficient HIV-1 replication. Interestingly, the A-rich sequence of this segment is highly conserved among HIV-1 isolates, which likely reflects the evolutionary tendency of HIV-1 to adopt A-rich sequences.
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27
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Aduri R, Briggs KT, Gorelick RJ, Marino JP. Molecular determinants of HIV-1 NCp7 chaperone activity in maturation of the HIV-1 dimerization initiation site. Nucleic Acids Res 2012; 41:2565-80. [PMID: 23275531 PMCID: PMC3575791 DOI: 10.1093/nar/gks1350] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Human immunodeficiency virus genome dimerization is initiated through an RNA-RNA kissing interaction formed via the dimerization initiation site (DIS) loop sequence, which has been proposed to be converted to a more thermodynamically stable linkage by the viral p7 form of the nucleocapsid protein (NC). Here, we systematically probed the role of specific amino acids of NCp7 in its chaperone activity in the DIS conversion using 2-aminopurine (2-AP) fluorescence and nuclear magnetic resonance spectroscopy. Through comparative analysis of NCp7 mutants, the presence of positively charged residues in the N-terminus was found to be essential for both helix destabilization and strand transfer functions. It was also observed that the presence and type of the Zn finger is important for NCp7 chaperone activity, but not the order of the Zn fingers. Swapping single aromatic residues between Zn fingers had a significant effect on NCp7 activity; however, these mutants did not exhibit the same activity as mutants in which the order of the Zn fingers was changed, indicating a functional role for other flanking residues. RNA chaperone activity is further correlated with NCp7 structure and interaction with RNA through comparative analysis of nuclear magnetic resonance spectra of NCp7 variants, and complexes of these proteins with the DIS dimer.
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Affiliation(s)
- Raviprasad Aduri
- Institute for Bioscience and Biotechnology Research of the University of Maryland and the National Institute of Standards and Technology, Rockville, MD 20850, USA
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28
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Kim T, Shapiro BA. The role of salt concentration and magnesium binding in HIV-1 subtype-A and subtype-B kissing loop monomer structures. J Biomol Struct Dyn 2012; 31:495-510. [PMID: 22881341 DOI: 10.1080/07391102.2012.706072] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
The subtype-B monomers of the human immunodeficiency virus type-1 (HIV-1) have experimentally been shown to dimerize at high salt concentration or in the presence of magnesium, while the dimerization of the subtype-A monomers requires magnesium binding at the G273 or G274 phosphate groups regardless of salt concentration. We used explicit solvent molecular dynamics (MD) simulations to investigate the conformational changes in subtype-A and -B monomers in different salt concentrations, and we found that our MD simulation results are consistent with those of experiments. At low salt concentration, hairpin loop structures of both subtypes were deformed and bases in the hairpin loop were turned inside. At high salt concentrations, the subtype-B monomer maintained the hairpin loop shape and most bases in the hairpin loop pointed out, while the subtype-A monomer showed a severe deformation. We also found that the flanking bases in the subtype-B stabilize the hairpin loop, while the flanking base G273 in the subtype-A caused a significant deformation. However, a bound magnesium ion at the G273 or G274 phosphate groups controlled the behavior of the G273 base and prevented the subtype-A monomer from deformation. We also applied restraints to both subtypes to examine the role of high salt concentration or magnesium binding. While restraints were applied, both subtypes at 0 M salt concentration maintained their shapes. However, when restraints were removed, they deformed significantly. Therefore, we suggest that the dimerization of both subtypes requires the proper conformation of the monomers which is induced by the appropriate salt strength and magnesium ion binding.
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Affiliation(s)
- Taejin Kim
- Center for Cancer Research Nanobiology Program, Frederick National Laboratory for Cancer Research, Frederick , MD 20872, USA
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Abstract
Transitions between the different conformational states play a critical role in many RNA catalytic and regulatory functions. In this study, we use the Kinetic Monte Carlo method to investigate the kinetic mechanism for the conformational switches between bistable RNA hairpins. We find three types of conformational switch pathways for RNA hairpins: refolding after complete unfolding, folding through basepair-exchange pathways and through pseudoknot-assisted pathways, respectively. The result of the competition between the three types of pathways depends mainly on the location of the rate-limiting base stacks (such as the GC base stacks) in the structures. Depending on the structural relationships between the two bistable hairpins, the conformational switch can follow single or multiple dominant pathways. The predicted folding pathways are supported by the activation energy results derived from the Arrhenius plot as well as the NMR spectroscopy data.
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Affiliation(s)
- Xiaojun XU
- Department of Physics and Department of Biochemistry University of Missouri, Columbia, MO 65211
| | - Shi-Jie CHEN
- Department of Physics and Department of Biochemistry University of Missouri, Columbia, MO 65211
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Batisse J, Guerrero S, Bernacchi S, Sleiman D, Gabus C, Darlix JL, Marquet R, Tisné C, Paillart JC. The role of Vif oligomerization and RNA chaperone activity in HIV-1 replication. Virus Res 2012; 169:361-76. [PMID: 22728817 DOI: 10.1016/j.virusres.2012.06.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2012] [Revised: 06/04/2012] [Accepted: 06/12/2012] [Indexed: 11/28/2022]
Abstract
The viral infectivity factor (Vif) is essential for the productive infection and dissemination of HIV-1 in non-permissive cells that involve most natural HIV-1 target cells. Vif counteracts the packaging of two cellular cytidine deaminases named APOBEC3G (A3G) and A3F by diverse mechanisms including the recruitment of an E3 ubiquitin ligase complex and the proteasomal degradation of A3G/A3F, the inhibition of A3G mRNA translation or by a direct competition mechanism. In addition, Vif appears to be an active partner of the late steps of viral replication by participating in virus assembly and Gag processing, thus regulating the final stage of virion formation notably genomic RNA dimerization and by inhibiting the initiation of reverse transcription. Vif is a small pleiotropic protein with multiple domains, and recent studies highlighted the importance of Vif conformation and flexibility in counteracting A3G and in binding RNA. In this review, we will focus on the oligomerization and RNA chaperone properties of Vif and show that the intrinsic disordered nature of some Vif domains could play an important role in virus assembly and replication. Experimental evidence demonstrating the RNA chaperone activity of Vif will be presented.
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Affiliation(s)
- Julien Batisse
- Architecture et Réactivité de l'ARN, Université de Strasbourg, CNRS, Institut de Biologie Moléculaire et Cellulaire, 15 rue René Descartes, 67084 Strasbourg, France
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31
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Sleiman D, Goldschmidt V, Barraud P, Marquet R, Paillart JC, Tisné C. Initiation of HIV-1 reverse transcription and functional role of nucleocapsid-mediated tRNA/viral genome interactions. Virus Res 2012; 169:324-39. [PMID: 22721779 DOI: 10.1016/j.virusres.2012.06.006] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Revised: 06/05/2012] [Accepted: 06/06/2012] [Indexed: 12/28/2022]
Abstract
HIV-1 reverse transcription is initiated from a tRNA(Lys)(3) molecule annealed to the viral RNA at the primer binding site (PBS). The annealing of tRNA(Lys)(3) requires the opening of its three-dimensional structure and RNA rearrangements to form an efficient initiation complex recognized by the reverse transcriptase. This annealing is mediated by the nucleocapsid protein (NC). In this paper, we first review the actual knowledge about HIV-1 viral RNA and tRNA(Lys)(3) structures. Then, we summarize the studies explaining how NC chaperones the formation of the tRNA(Lys)(3)/PBS binary complex. Additional NMR data that investigated the NC interaction with tRNA(Lys)(3) D-loop are presented. Lastly, we focused on the additional interactions occurring between tRNA(Lys)(3) and the viral RNA and showed that they are dependent on HIV-1 isolates, i.e. the sequence and the structure of the viral RNA.
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Affiliation(s)
- Dona Sleiman
- Laboratoire de Cristallographie et RMN biologiques, Université Paris-Descartes, CNRS UMR 8015, 4 avenue de l'Observatoire, 75006 Paris, France
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32
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Cao S, Chen SJ. Structure and stability of RNA/RNA kissing complex: with application to HIV dimerization initiation signal. RNA (NEW YORK, N.Y.) 2011; 17:2130-43. [PMID: 22028361 PMCID: PMC3222126 DOI: 10.1261/rna.026658.111] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2011] [Accepted: 09/12/2011] [Indexed: 05/24/2023]
Abstract
We develop a statistical mechanical model to predict the structure and folding stability of the RNA/RNA kissing-loop complex. One of the key ingredients of the theory is the conformational entropy for the RNA/RNA kissing complex. We employ the recently developed virtual bond-based RNA folding model (Vfold model) to evaluate the entropy parameters for the different types of kissing loops. A benchmark test against experiments suggests that the entropy calculation is reliable. As an application of the model, we apply the model to investigate the structure and folding thermodynamics for the kissing complex of the HIV-1 dimerization initiation signal. With the physics-based energetic parameters, we compute the free energy landscape for the HIV-1 dimer. From the energy landscape, we identify two minimal free energy structures, which correspond to the kissing-loop dimer and the extended-duplex dimer, respectively. The results support the two-step dimerization process for the HIV-1 replication cycle. Furthermore, based on the Vfold model and energy minimization, the theory can predict the native structure as well as the local minima in the free energy landscape. The root-mean-square deviations (RMSDs) for the predicted kissing-loop dimer and extended-duplex dimer are ~3.0 Å. The method developed here provides a new method to study the RNA/RNA kissing complex.
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Affiliation(s)
- Song Cao
- Department of Physics and Department of Biochemistry, University of Missouri, Columbia, Missouri 65211, USA
| | - Shi-Jie Chen
- Department of Physics and Department of Biochemistry, University of Missouri, Columbia, Missouri 65211, USA
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Jalaguier P, Turcotte K, Danylo A, Cantin R, Tremblay MJ. Efficient production of HIV-1 virus-like particles from a mammalian expression vector requires the N-terminal capsid domain. PLoS One 2011; 6:e28314. [PMID: 22140574 PMCID: PMC3227654 DOI: 10.1371/journal.pone.0028314] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Accepted: 11/06/2011] [Indexed: 11/19/2022] Open
Abstract
It is now well accepted that the structural protein Pr55(Gag) is sufficient by itself to produce HIV-1 virus-like particles (VLPs). This polyprotein precursor contains different domains including matrix, capsid, SP1, nucleocapsid, SP2 and p6. In the present study, we wanted to determine by mutagenesis which region(s) is essential to the production of VLPs when Pr55(Gag) is inserted in a mammalian expression vector, which allows studying the protein of interest in the absence of other viral proteins. To do so, we first studied a minimal Pr55(Gag) sequence called Gag min that was used previously. We found that Gag min fails to produce VLPs when expressed in an expression vector instead of within a molecular clone. This failure occurs early in the cell at the assembly of viral proteins. We then generated a series of deletion and substitution mutants, and examined their ability to produce VLPs by combining biochemical and microscopic approaches. We demonstrate that the matrix region is not necessary, but that the efficiency of VLP production depends strongly on the presence of its basic region. Moreover, the presence of the N-terminal domain of capsid is required for VLP production when Gag is expressed alone. These findings, combined with previous observations indicating that HIV-1 Pr55(Gag)-derived VLPs act as potent stimulators of innate and acquired immunity, make the use of this strategy worth considering for vaccine development.
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Affiliation(s)
- Pascal Jalaguier
- Centre de Recherche en Infectiologie, Centre Hospitalier Universitaire de Québec – CHUL, Québec, Canada
| | - Karine Turcotte
- Centre de Recherche en Infectiologie, Centre Hospitalier Universitaire de Québec – CHUL, Québec, Canada
| | - Alexis Danylo
- Centre de Recherche en Infectiologie, Centre Hospitalier Universitaire de Québec – CHUL, Québec, Canada
| | - Réjean Cantin
- Centre de Recherche en Infectiologie, Centre Hospitalier Universitaire de Québec – CHUL, Québec, Canada
| | - Michel J. Tremblay
- Centre de Recherche en Infectiologie, Centre Hospitalier Universitaire de Québec – CHUL, Québec, Canada
- Département de Microbiologie-Infectiologie et Immunologie, Faculté de médecine, Université Laval, Québec, Canada
- * E-mail:
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34
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[What's going on post-budding?]. Uirusu 2011; 61:91-8. [PMID: 21972560 DOI: 10.2222/jsv.61.91] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
In general, the retrovirus particles become infectious on post-budding with cleavages of structural protein Gag by viral protease. Protease defective mutants bud particles normally, but the particles are non-infectious and called donuts-like particle because of their morphology. The viral genomes inside the donuts-like particles form very fragile dimer, which are far different from those in wild-type particles. The ordered particle maturation process is essential for infectivity of virus, but its mechanism largely remains unclear. We have constructed HIV-1 Gag cleavage site mutants to enable the steady state observation of virion maturation steps, and precisely study Gag processing, RNA dimerization, virion morphology and infectivity. As results, we found that these process progressed synchronously, but each transition point did not coincide completely. The mutual relationship between viral protein and RNA maturation is discussed for a further understanding of the retroviral life cycle.
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35
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Lu K, Heng X, Summers MF. Structural determinants and mechanism of HIV-1 genome packaging. J Mol Biol 2011; 410:609-33. [PMID: 21762803 DOI: 10.1016/j.jmb.2011.04.029] [Citation(s) in RCA: 186] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Revised: 04/11/2011] [Accepted: 04/11/2011] [Indexed: 11/30/2022]
Abstract
Like all retroviruses, the human immunodeficiency virus selectively packages two copies of its unspliced RNA genome, both of which are utilized for strand-transfer-mediated recombination during reverse transcription-a process that enables rapid evolution under environmental and chemotherapeutic pressures. The viral RNA appears to be selected for packaging as a dimer, and there is evidence that dimerization and packaging are mechanistically coupled. Both processes are mediated by interactions between the nucleocapsid domains of a small number of assembling viral Gag polyproteins and RNA elements within the 5'-untranslated region of the genome. A number of secondary structures have been predicted for regions of the genome that are responsible for packaging, and high-resolution structures have been determined for a few small RNA fragments and protein-RNA complexes. However, major questions regarding the RNA structures (and potentially the structural changes) that are responsible for dimeric genome selection remain unanswered. Here, we review efforts that have been made to identify the molecular determinants and mechanism of human immunodeficiency virus type 1 genome packaging.
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Affiliation(s)
- Kun Lu
- Howard Hughes Medical Institute and Department of Chemistry and Biochemistry, University of Maryland Baltimore County, Baltimore, MD 21250, USA
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Pallesen J. Structure of the HIV-1 5' untranslated region dimer alone and in complex with gold nanocolloids: support of a TAR-TAR-containing 5' dimer linkage site (DLS) and a 3' DIS-DIS-containing DLS. Biochemistry 2011; 50:6170-7. [PMID: 21663314 DOI: 10.1021/bi200488h] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The formation of a genomic RNA dimer is critical for the HIV-1 replication cycle, and dimerization is known to initiate within the 5'UTR (5' untranslated region) of the viral RNA. However, the 5'UTR constitutes the 335 terminal nucleotides, and because of this considerable size, it has been difficult to study the global structure using conventional structural methods. Here, the atomic force microscope has been used to directly visualize the dimer formed from RNAs including HIV-1 nucleotides 1-744. Gold nanocolloids were deposited on the primer binding site regions in the dimer as an internal control. The dimer showed distinct ring morphology with up to two gold nanocolloids deposited within the ring and one or two strands extending from the ring. This morphology implies a dimer including a DIS-DIS (dimerization initiation site)-containing 3' dimer linkage site (DLS) and a TAR-TAR (trans-activation region)-containing 5'DLS. Furthermore, the dimer was formed under the influence of Mg(2+) and was imaged with an atomic force microscope under buffer conditions. The overall ring morphology containing a 5'DLS and a 3'DLS with one or two strands extending from it was conserved in these atomic force microscopy images. This indicates that the observed dimer morphology is physiologically significant. Moreover, evidence of multiple dimer interstrand contacts downstream of the major splice donor were observed, which indicates a component in the selection of full-length genomic RNA in dimer formation during virion packaging.
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Affiliation(s)
- Jesper Pallesen
- Department of Biochemistry and Molecular Biophysics, Howard Hughes Medical Institute, Columbia University, New York, New York 10032, United States.
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37
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Piekna-Przybylska D, Bambara RA. Requirements for efficient minus strand strong-stop DNA transfer in human immunodeficiency virus 1. RNA Biol 2011; 8:230-6. [PMID: 21444998 DOI: 10.4161/rna.8.2.14802] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
After HIV-1 enters a human cell, its RNA genome is converted into double stranded DNA during the multistep process of reverse transcription. First (minus) strand DNA synthesis is initiated near the 5' end of the viral RNA, where only a short fragment of the genome is copied. In order to continue DNA synthesis the virus employs a complicated mechanism, which enables transferring of the growing minus strand DNA to a remote position at the genomic 3' end. This is called minus strand DNA transfer. The transfer enables regeneration of long terminal repeat sequences, which are crucial for viral genomic DNA integration into the host chromosome. Numerous factors have been identified that stimulate minus strand DNA transfer. In this review we focus on describing protein-RNA and RNA-RNA interactions, as well as RNA structural features, known to facilitate this step in reverse transcription.
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Affiliation(s)
- Dorota Piekna-Przybylska
- Department of Biochemistry and Biophysics, and the Center for RNA Biology, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
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38
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Ohishi M, Nakano T, Sakuragi S, Shioda T, Sano K, Sakuragi JI. The relationship between HIV-1 genome RNA dimerization, virion maturation and infectivity. Nucleic Acids Res 2010; 39:3404-17. [PMID: 21186186 PMCID: PMC3082877 DOI: 10.1093/nar/gkq1314] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The relationship between virion protein maturation and genomic RNA dimerization of human immunodeficiency virus type 1 (HIV-1) remains incompletely understood. We have constructed HIV-1 Gag cleavage site mutants to enable the steady state observation of virion maturation steps, and precisely study Gag processing, RNA dimerization, virion morphology and infectivity. Within the virion maturation process, the RNA dimer stabilization begins during the primary cleavage (p2-NC) of Pr55 Gag. However, the primary cleavage alone is not sufficient, and the ensuing cleavages are required for the completion of dimerization. From our observations, the increase of cleavage products may not put a threshold on the transition from fragile to stable dimeric RNA. Most of the RNA dimerization process did not require viral core formation, and particle morphology dynamics during viral maturation did not completely synchronize with the transition of dimeric RNA status. Although the endogenous virion RT activity was fully acquired at the initial step of maturation, the following process was necessary for viral DNA production in infected cell, suggesting the maturation of viral RNA/protein plays critical role for viral infectivity other than RT process.
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Affiliation(s)
- Masahisa Ohishi
- Department of Viral Infections, Research Institute for Microbial Diseases, Osaka University Suita, Osaka 565-0871, Japan
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39
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Wu T, Datta SA, Mitra M, Gorelick RJ, Rein A, Levin JG. Fundamental differences between the nucleic acid chaperone activities of HIV-1 nucleocapsid protein and Gag or Gag-derived proteins: biological implications. Virology 2010; 405:556-67. [PMID: 20655566 PMCID: PMC2963451 DOI: 10.1016/j.virol.2010.06.042] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2010] [Revised: 05/16/2010] [Accepted: 06/23/2010] [Indexed: 01/31/2023]
Abstract
The HIV-1 Gag polyprotein precursor has multiple domains including nucleocapsid (NC). Although mature NC and NC embedded in Gag are nucleic acid chaperones (proteins that remodel nucleic acid structure), few studies include detailed analysis of the chaperone activity of partially processed Gag proteins and comparison with NC and Gag. Here we address this issue by using a reconstituted minus-strand transfer system. NC and NC-containing Gag proteins exhibited annealing and duplex destabilizing activities required for strand transfer. Surprisingly, unlike NC, with increasing concentrations, Gag proteins drastically inhibited the DNA elongation step. This result is consistent with "nucleic acid-driven multimerization" of Gag and the reported slow dissociation of Gag from bound nucleic acid, which prevent reverse transcriptase from traversing the template ("roadblock" mechanism). Our findings illustrate one reason why NC (and not Gag) has evolved as a critical cofactor in reverse transcription, a paradigm that might also extend to other retrovirus systems.
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Affiliation(s)
- Tiyun Wu
- Laboratory of Molecular Genetics, Program in Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Building 6B, Room 216, 6 Center Drive, Bethesda, MD 20892-2780, USA
| | - Siddhartha A.K. Datta
- HIV Drug Resistance Program, National Cancer Institute-Frederick, Frederick, MD 21702-1201, USA
| | - Mithun Mitra
- Laboratory of Molecular Genetics, Program in Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Building 6B, Room 216, 6 Center Drive, Bethesda, MD 20892-2780, USA
| | - Robert J. Gorelick
- AIDS and Cancer Virus Program, SAIC-Frederick, Inc., National Cancer Institute-Frederick, Frederick, MD 21702-1201, USA
| | - Alan Rein
- HIV Drug Resistance Program, National Cancer Institute-Frederick, Frederick, MD 21702-1201, USA
| | - Judith G. Levin
- Laboratory of Molecular Genetics, Program in Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Building 6B, Room 216, 6 Center Drive, Bethesda, MD 20892-2780, USA
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Jalalirad M, Laughrea M. Formation of immature and mature genomic RNA dimers in wild-type and protease-inactive HIV-1: differential roles of the Gag polyprotein, nucleocapsid proteins NCp15, NCp9, NCp7, and the dimerization initiation site. Virology 2010; 407:225-36. [PMID: 20828778 DOI: 10.1016/j.virol.2010.08.013] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2010] [Revised: 08/06/2010] [Accepted: 08/13/2010] [Indexed: 12/22/2022]
Abstract
Formation of immature genomic RNA (gRNA) dimers is exquisitely nucleocapsid (NC)-dependent in protease-inactive (PR-in) HIV-1. This establishes that Pr55gag/Pr160gag-pol has NC-dependent chaperone activity within intact HIV-1. Mutations in the proximal zinc finger and the linker of the NC sequence of Pr55gag/Pr160gag-pol abolish gRNA dimerization in PR-in HIV-1. In wild type, where the NC of Pr55gag is processed into progressively smaller proteins termed NCp15 (NCp7-p1-p6), NCp9 (NCp7-p1) and NCp7, formation of immature dimers is much swifter than in PR-in HIV-1. NCp7 and NCp15 direct this rapid accumulation. NCp9 is sluggish in this process, but it stimulates the transition from immature to mature gRNA dimer as well as NCp7 and much better than NCp15. The amino-terminus, proximal zinc finger, linker, and distal zinc finger of NCp7 contribute to this maturation event in intact HIV-1. The DIS is a dimerization initiation site for all immature gRNA dimers, irrespective of their mechanism of formation.
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Affiliation(s)
- Mohammad Jalalirad
- McGill AIDS Center, Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal QC, Canada H3T 1E2
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Ristic N, Chin MPS. Mutations in matrix and SP1 repair the packaging specificity of a Human Immunodeficiency Virus Type 1 mutant by reducing the association of Gag with spliced viral RNA. Retrovirology 2010; 7:73. [PMID: 20825656 PMCID: PMC2941742 DOI: 10.1186/1742-4690-7-73] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2010] [Accepted: 09/08/2010] [Indexed: 12/02/2022] Open
Abstract
Background The viral genome of HIV-1 contains several secondary structures that are important for regulating viral replication. The stem-loop 1 (SL1) sequence in the 5' untranslated region directs HIV-1 genomic RNA dimerization and packaging into the virion. Without SL1, HIV-1 cannot replicate in human T cell lines. The replication restriction phenotype in the SL1 deletion mutant appears to be multifactorial, with defects in viral RNA dimerization and packaging in producer cells as well as in reverse transcription of the viral RNA in infected cells. In this study, we sought to characterize SL1 mutant replication restrictions and provide insights into the underlying mechanisms of compensation in revertants. Results HIV-1 lacking SL1 (NLΔSL1) did not replicate in PM-1 cells until two independent non-synonymous mutations emerged: G913A in the matrix domain (E42K) on day 18 postinfection and C1907T in the SP1 domain (P10L) on day 11 postinfection. NLΔSL1 revertants carrying either compensatory mutation showed enhanced infectivity in PM-1 cells. The SL1 revertants produced significantly more infectious particles per nanogram of p24 than did NLΔSL1. The SL1 deletion mutant packaged less HIV-1 genomic RNA and more cellular RNA, particularly signal recognition particle RNA, in the virion than the wild-type. NLΔSL1 also packaged 3- to 4-fold more spliced HIV mRNA into the virion, potentially interfering with infectious virus production. In contrast, both revertants encapsidated 2.5- to 5-fold less of these HIV-1 mRNA species. Quantitative RT-PCR analysis of RNA cross-linked with Gag in formaldehyde-fixed cells demonstrated that the compensatory mutations reduced the association between Gag and spliced HIV-1 RNA, thereby effectively preventing these RNAs from being packaged into the virion. The reduction of spliced viral RNA in the virion may have a major role in facilitating infectious virus production, thus restoring the infectivity of NLΔSL1. Conclusions HIV-1 evolved to overcome a deletion in SL1 and restored infectivity by acquiring compensatory mutations in the N-terminal matrix or SP1 domain of Gag. These data shed light on the functions of the N-terminal matrix and SP1 domains and suggest that both regions may have a role in Gag interactions with spliced viral RNA.
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Affiliation(s)
- Natalia Ristic
- Aaron Diamond AIDS Research Center, The Rockefeller University, New York, New York, USA
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42
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Ennifar E, Walter P, Dumas P. Cation-dependent cleavage of the duplex form of the subtype-B HIV-1 RNA dimerization initiation site. Nucleic Acids Res 2010; 38:5807-16. [PMID: 20460458 PMCID: PMC2943608 DOI: 10.1093/nar/gkq344] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The crystal structure of subtype-B HIV-1 genomic RNA Dimerization Initiation Site duplex revealed chain cleavage at a specific position resulting in 3'-phosphate and 5'-hydroxyl termini. A crystallographic analysis showed that Ba(2+), Mn(2+), Co(2+) and Zn(2+) bind specifically on a guanine base close to the cleaved position. The crystal structures also point to a necessary conformational change to induce an 'in-line' geometry at the cleavage site. In solution, divalent cations increased the rate of cleavage with pH/pKa compensation, indicating that a cation-bound hydroxide anion is responsible for the cleavage. We propose a 'Trojan horse' mechanism, possibly of general interest, wherein a doubly charged cation hosted near the cleavage site as a 'harmless' species is further transformed in situ into an 'aggressive' species carrying a hydroxide anion.
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Affiliation(s)
| | | | - Philippe Dumas
- *To whom correspondence should be addressed. Tel: +33 388 41 70 02; Fax: +33 388 60 22 18;
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43
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Chung J, Ulyanov NB, Guilbert C, Mujeeb A, James TL. Binding characteristics of small molecules that mimic nucleocapsid protein-induced maturation of stem-loop 1 of HIV-1 RNA. Biochemistry 2010; 49:6341-51. [PMID: 20565056 PMCID: PMC2921804 DOI: 10.1021/bi100660r] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
As a retrovirus, the human immunodeficiency virus (HIV-1) packages two copies of the RNA genome as a dimer in the infectious virion. Dimerization is initiated at the dimer initiation site (DIS) which encompasses stem-loop 1 (SL1) in the 5'-UTR of the genome. Study of genomic dimerization has been facilitated by the discovery that short RNA fragments containing SL1 can dimerize spontaneously without any protein factors. On the basis of the palindromic nature of SL1, a kissing loop model has been proposed. First, a metastable kissing dimer is formed via standard Watson-Crick base pairs and then converted into a more stable extended dimer by the viral nucleocapsid protein (NCp7). This dimer maturation in vitro is believed to mimic initial steps in the RNA maturation in vivo, which is correlated with viral infectivity. We previously discovered a small molecule activator, Lys-Ala-7-amido-4-methylcoumarin (KA-AMC), which facilitates dimer maturation in vitro, and determined aspects of its structure-activity relationship. In this report, we present measurements of the binding affinity of the activators and characterization of their interactions with the SL1 RNA. Guanidinium groups and increasing positive charge on the side chain enhance affinity and activity, but features in the aromatic ring at least partially decouple affinity from activity. Although KA-AMC can bind to multiple structural motifs, the NMR study showed KA-AMC preferentially binds to unique structural motifs, such as the palindromic loop and the G-rich internal loop in the SL1 RNA. NCp7 binds to SL1 only 1 order of magnitude more tightly than the best small molecule ligand tested. This study provides guidelines for the design of superior small molecules that bind to the SL1 RNA that have the potential of being developed as an antiviral by interfering with SL1-NCp7 interaction at the packaging and/or maturation stages.
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Affiliation(s)
| | - Nikolai B. Ulyanov
- Department of Pharmaceutical Chemistry, University of California, San Francisco, 600 16 Street, San Francisco, California 94158-2517
| | - Christophe Guilbert
- Department of Pharmaceutical Chemistry, University of California, San Francisco, 600 16 Street, San Francisco, California 94158-2517
| | | | - Thomas L. James
- Department of Pharmaceutical Chemistry, University of California, San Francisco, 600 16 Street, San Francisco, California 94158-2517
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Sánchez-Luque FJ, Reyes-Darias JA, Puerta-Fernández E, Berzal-Herranz A. Inhibition of HIV-1 replication and dimerization interference by dual inhibitory RNAs. Molecules 2010; 15:4757-72. [PMID: 20657391 PMCID: PMC6257581 DOI: 10.3390/molecules15074757] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2010] [Revised: 06/28/2010] [Accepted: 07/01/2010] [Indexed: 02/05/2023] Open
Abstract
The 5'-untranslated region (5'UTR) of the HIV-1 RNA is an attractive target for engineered ribozymes due to its high sequence and structural conservation. This region encodes several conserved structural RNA domains essential in key processes of the viral replication and infection cycles. This paper reports the inhibitory effects of catalytic antisense RNAs composed of two inhibitory RNA domains: an engineered ribozyme targeting the 5' UTR and a decoy or antisense domain of the dimerization initiation site (DIS). These chimeric molecules are able to cleave the HIV-1 5'UTR efficiently and prevent viral genome dimerization in vitro. Furthermore, catalytic antisense RNAs inhibited viral production up to 90% measured as p24 antigen levels in ex vivo assays. The use of chimeric RNA molecules targeting different domains represents an attractive antiviral strategy to be explored for the prevention of side effects from current drugs and of the rapid emergence of escape variants of HIV-1.
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Affiliation(s)
- Francisco J. Sánchez-Luque
- Instituto de Parasitología y Biomedicina “López-Neyra”, CSIC, P.T. Ciencias de la Salud, Av. del Conocimiento s/n, Armilla, 18100 Granada, Spain; E-Mails: (F.J.S.-L.); (J.A.R.-D.)
| | - José A. Reyes-Darias
- Instituto de Parasitología y Biomedicina “López-Neyra”, CSIC, P.T. Ciencias de la Salud, Av. del Conocimiento s/n, Armilla, 18100 Granada, Spain; E-Mails: (F.J.S.-L.); (J.A.R.-D.)
| | - Elena Puerta-Fernández
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-CSIC. Américo Vespucio s/n, Isla de la Cartuja, 41092 Sevilla, Spain; E-Mail: (E.P.-F.)
| | - Alfredo Berzal-Herranz
- Instituto de Parasitología y Biomedicina “López-Neyra”, CSIC, P.T. Ciencias de la Salud, Av. del Conocimiento s/n, Armilla, 18100 Granada, Spain; E-Mails: (F.J.S.-L.); (J.A.R.-D.)
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +34 958 181 648; Fax: +34 958 181 632
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Joubert MK, Kinsley N, Capovilla A, Sewell BT, Jaffer MA, Khati M. A Modeled Structure of an Aptamer−gp120 Complex Provides Insight into the Mechanism of HIV-1 Neutralization. Biochemistry 2010; 49:5880-90. [DOI: 10.1021/bi100301k] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | - Nichole Kinsley
- Elevation Biotech, 8 Blackwood Avenue, Parktown, Johannesburg 2193, South Africa
| | - Alexio Capovilla
- Elevation Biotech, 8 Blackwood Avenue, Parktown, Johannesburg 2193, South Africa
- Department of Molecular Medicine and Haematology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg 2193, South Africa
| | - B. Trevor Sewell
- Electron Microscope Unit, University of Cape Town, Rondebosch 7701, South Africa
| | - Mohamed A. Jaffer
- Electron Microscope Unit, University of Cape Town, Rondebosch 7701, South Africa
| | - Makobetsa Khati
- CSIR Biosciences, P.O. Box 395, Pretoria 0001, South Africa
- Department of Medicine, Groote Schuur Hospital and University of Cape Town, Cape Town, South Africa
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Athavale SS, Ouyang W, McPike MP, Hudson BS, Borer PN. Effects of the nature and concentration of salt on the interaction of the HIV-1 nucleocapsid protein with SL3 RNA. Biochemistry 2010; 49:3525-33. [PMID: 20359247 DOI: 10.1021/bi901279e] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The mature nucleocapsid protein of HIV-1, NCp7, and the NC domains in gag precursors are attractive targets for anti-AIDS drug discovery. The stability of the 1:1 complex of NCp7 with a 20mer mimic of stem-loop 3 RNA (SL3, also called psi-RNA, in the packaging domain of genomic RNA) is strongly affected by changes in ionic strength. NC domains recognize and specifically package genomic HIV-1 RNA, while electrostatic attractions and high concentrations of protein and RNA drive NCp7 to completely coat the RNA in the mature virion. The specific interactions of NCp7 binding to loop bases of SL3 produce 1:1 complexes in solutions that have a NaCl concentration of >or=0.2 M, while the electrostatic interactions can dominate at <or=0.15 M NaCl, leading to complexes that have a mainly 1:2 RNA:protein ratio. Persistent, nonequilibrium mixtures of 1:1 and protein-excess complexes can exist at these lower salt concentrations, where the distribution of complexes depends on the order of addition of RNA and protein. Adding salt causes rapid rearrangement of metastable multiprotein complexes to a 1:1 ratio. The stability of complexes is also affected by the nature of the added salt, with 0.018 M MgCl(2) and added 0.200 M NaCl producing the same K(d) (21 +/- 2 nM); acetate ion stabilizes the 1:1 complex by a factor of more than 2 compared to the same concentration of chloride ion. Maintaining a salt concentration of 0.2 M NaCl or 18 mM MgCl(2) is sufficient for experiments to distinguish drug candidates that disrupt the specific SL3-NCp7 interactions in the 1:1 complex.
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Affiliation(s)
- Shreyas S Athavale
- Department of Chemistry, Syracuse University, Syracuse, New York 13244, USA
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Goldschmidt V, Miller Jenkins LM, de Rocquigny H, Darlix JL, Mély Y. The nucleocapsid protein of HIV-1 as a promising therapeutic target for antiviral drugs. ACTA ACUST UNITED AC 2010. [DOI: 10.2217/hiv.10.3] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The nucleocapsid protein (NCp7) is a major HIV-1 structural protein that plays key roles in viral replication, mainly through its conserved zinc fingers that direct specific interactions with the viral nucleic acids. Owing to its high degree of conservation and critical functions, NCp7 represents a target of choice for drugs that can potentially complement HAART, thus possibly impairing the circulation of drug-resistant HIV-1 strains. Zinc ejectors showing potent antiretroviral activity were developed, but early generations suffered from limited selectively and significant toxicity. Compounds with improved selectivity have been developed and are being explored as topical microbicide candidates. Several classes of molecules inhibiting the interaction of NCp7 with the viral nucleic acids have also been developed. Although small molecules would be more suited for drug development, most molecules selected by screening showed limited antiretroviral activity. Peptides and RNA aptamers appear to be more promising, but the mechanism of their antiretroviral activity remains elusive. Substantial and more concerted efforts are needed to further develop anti-HIV drugs targeting NCp7 and bring them to the clinic.
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Affiliation(s)
- Valérie Goldschmidt
- Laboratoire de Biophotonique et Pharmacologie, UMR-CNRS 7213, Faculté de Pharmacie, Université de Strasbourg, 74 route du Rhin, 67401 Illkirch-Cedex, France
| | - Lisa M Miller Jenkins
- Laboratory of Cell Biology, NCI, National Institutes of Health, Bethesda, MD 20892, USA
| | - Hugues de Rocquigny
- Laboratoire de Biophotonique et Pharmacologie, UMR-CNRS 7213, Faculté de Pharmacie, Université de Strasbourg, 74 route du Rhin, 67401 Illkirch-Cedex, France
| | - Jean-Luc Darlix
- LaboRetro, Unité de Virologie Humaine INSERM 758, Ecole Normale Supérieure de Lyon, 46 allée d’Italie, 69364 Lyon, France
| | - Yves Mély
- Laboratoire de Biophotonique et Pharmacologie, UMR-CNRS 7213, Faculté de Pharmacie, Université de Strasbourg, 74 route du Rhin, 67401 Illkirch-Cedex, France
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Kaluzhny DN, Minyat EE. Interaction of the dimeric form of retroviral RNA with paromonycin and magnesium as revealed using 2-aminopurine fluorescence. Mol Biol 2009. [DOI: 10.1134/s0026893309040141] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Turner KB, Kohlway AS, Hagan NA, Fabris D. Noncovalent probes for the investigation of structure and dynamics of protein-nucleic acid assemblies: the case of NC-mediated dimerization of genomic RNA in HIV-1. Biopolymers 2009; 91:283-96. [PMID: 18946871 DOI: 10.1002/bip.21107] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The nature of specific RNA-RNA and protein-RNA interactions involved in the process of genome dimerization and isomerization in HIV-1, which is mediated in vitro by stemloop 1 (SL1) of the packaging signal and by the nucleocapsid (NC) domain of the viral Gag polyprotein, was investigated by using archetypical nucleic acid ligands as noncovalent probes. Small-molecule ligands make contact with their target substrates through complex combinations of H-bonds, salt bridges, and hydrophobic interactions. Therefore, their binding patterns assessed by electrospray ionization mass spectrometry can provide valuable insights into the factors determining specific recognition between species involved in biopolymer assemblies. In the case of SL1, dimerization and isomerization create unique structural features capable of sustaining stable interactions with classic nucleic acid ligands. The binding modes exhibited by intercalators and minor groove binders were adversely affected by the significant distortion of the duplex formed by palindrome annealing in the kissing-loop (KL) dimer, whereas the modes observed for the corresponding extended duplex (ED) confirmed a more regular helical structure. Consistent with the ability to establish electrostatic interactions with highly negative pockets typical of helix anomalies, polycationic aminoglycosides bound to the stem-bulge motif conserved in all SL1 conformers, to the unpaired nucleotides located at the hinge between kissing hairpins in KL, and to the exposed bases flanking the palindrome duplex in ED. The patterns afforded by intercalators and minor groove binders did not display detectable variations when the corresponding NC-SL1 complexes were submitted to probing. In contrast, aminoglycosides displayed the ability to compete with the protein for overlapping sites, producing opposite effects on the isomerization process. Indeed, displacing NC from the stem-bulges of the KL dimer induced inhibition of stem melting and decreased the efficiency of isomerization. Competition for the hinge region, instead, eliminated the NC stabilization of a grip motif formed by nucleobases of opposite strands, thus facilitating the strand-exchange required for isomerization. These noncovalent probes provided further evidence that the structural context of the actual binding sites has significant influence on the chaperone activities of NC, which should be taken in account when developing potential drug candidates aimed at disrupting genome dimerization and isomerization in HIV-1.
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Affiliation(s)
- Kevin B Turner
- Department of Chemistry and Biochemistry, University of Maryland Baltimore County, Baltimore, MD, USA
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Sarzyńska J, Réblová K, Šponer J, Kuliński T. Conformational transitions of flanking purines in HIV-1 RNA dimerization initiation site kissing complexes studied by CHARMM explicit solvent molecular dynamics. Biopolymers 2008; 89:732-46. [DOI: 10.1002/bip.21001] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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