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Gien H, Morse M, McCauley MJ, Rouzina I, Gorelick RJ, Williams MC. Cationic Residues of the HIV-1 Nucleocapsid Protein Enable DNA Condensation to Maintain Viral Core Particle Stability during Reverse Transcription. Viruses 2024; 16:872. [PMID: 38932164 PMCID: PMC11209390 DOI: 10.3390/v16060872] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2024] [Revised: 04/30/2024] [Accepted: 05/23/2024] [Indexed: 06/28/2024] Open
Abstract
The HIV-1 nucleocapsid protein (NC) is a multifunctional viral protein necessary for HIV-1 replication. Recent studies have demonstrated that reverse transcription (RT) completes in the intact viral capsid, and the timing of RT and uncoating are correlated. How the small viral core stably contains the ~10 kbp double stranded (ds) DNA product of RT, and the role of NC in this process, are not well understood. We showed previously that NC binds and saturates dsDNA in a non-specific electrostatic binding mode that triggers uniform DNA self-attraction, condensing dsDNA into a tight globule against extending forces up to 10 pN. In this study, we use optical tweezers and atomic force microscopy to characterize the role of NC's basic residues in dsDNA condensation. Basic residue mutations of NC lead to defective interaction with the dsDNA substrate, with the constant force plateau condensation observed with wild-type (WT) NC missing or diminished. These results suggest that NC's high positive charge is essential to its dsDNA condensing activity, and electrostatic interactions involving NC's basic residues are responsible in large part for the conformation, size, and stability of the dsDNA-protein complex inside the viral core. We observe DNA re-solubilization and charge reversal in the presence of excess NC, consistent with the electrostatic nature of NC-induced DNA condensation. Previous studies of HIV-1 replication in the presence of the same cationic residue mutations in NC showed significant defects in both single- and multiple-round viral infectivity. Although NC participates in many stages of viral replication, our results are consistent with the hypothesis that cationic residue mutations inhibit genomic DNA condensation, resulting in increased premature capsid uncoating and contributing to viral replication defects.
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Affiliation(s)
- Helena Gien
- Department of Physics, Northeastern University, Boston, MA 02115, USA; (H.G.); (M.M.); (M.J.M.)
| | - Michael Morse
- Department of Physics, Northeastern University, Boston, MA 02115, USA; (H.G.); (M.M.); (M.J.M.)
| | - Micah J. McCauley
- Department of Physics, Northeastern University, Boston, MA 02115, USA; (H.G.); (M.M.); (M.J.M.)
| | - Ioulia Rouzina
- Department of Chemistry and Biochemistry, Center for Retroviral Research and Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA;
| | - Robert J. Gorelick
- AIDS and Cancer Virus Program, Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA;
| | - Mark C. Williams
- Department of Physics, Northeastern University, Boston, MA 02115, USA; (H.G.); (M.M.); (M.J.M.)
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2
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Lyonnais S, Sadiq SK, Lorca-Oró C, Dufau L, Nieto-Marquez S, Escribà T, Gabrielli N, Tan X, Ouizougun-Oubari M, Okoronkwo J, Reboud-Ravaux M, Gatell JM, Marquet R, Paillart JC, Meyerhans A, Tisné C, Gorelick RJ, Mirambeau G. The HIV-1 Nucleocapsid Regulates Its Own Condensation by Phase-Separated Activity-Enhancing Sequestration of the Viral Protease during Maturation. Viruses 2021; 13:v13112312. [PMID: 34835118 PMCID: PMC8625067 DOI: 10.3390/v13112312] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 11/09/2021] [Accepted: 11/11/2021] [Indexed: 02/07/2023] Open
Abstract
A growing number of studies indicate that mRNAs and long ncRNAs can affect protein populations by assembling dynamic ribonucleoprotein (RNP) granules. These phase-separated molecular ‘sponges’, stabilized by quinary (transient and weak) interactions, control proteins involved in numerous biological functions. Retroviruses such as HIV-1 form by self-assembly when their genomic RNA (gRNA) traps Gag and GagPol polyprotein precursors. Infectivity requires extracellular budding of the particle followed by maturation, an ordered processing of ∼2400 Gag and ∼120 GagPol by the viral protease (PR). This leads to a condensed gRNA-NCp7 nucleocapsid and a CAp24-self-assembled capsid surrounding the RNP. The choreography by which all of these components dynamically interact during virus maturation is one of the missing milestones to fully depict the HIV life cycle. Here, we describe how HIV-1 has evolved a dynamic RNP granule with successive weak–strong–moderate quinary NC-gRNA networks during the sequential processing of the GagNC domain. We also reveal two palindromic RNA-binding triads on NC, KxxFxxQ and QxxFxxK, that provide quinary NC-gRNA interactions. Consequently, the nucleocapsid complex appears properly aggregated for capsid reassembly and reverse transcription, mandatory processes for viral infectivity. We show that PR is sequestered within this RNP and drives its maturation/condensation within minutes, this process being most effective at the end of budding. We anticipate such findings will stimulate further investigations of quinary interactions and emergent mechanisms in crowded environments throughout the wide and growing array of RNP granules.
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Affiliation(s)
- Sébastien Lyonnais
- Infectious Disease & AIDS Research Unit, Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Villaroel 170, 08036 Barcelona, Spain; (C.L.-O.); (S.N.-M.); (T.E.); (N.G.); (X.T.); (M.O.-O.); (J.O.); (J.M.G.)
- Centre d’Etudes des Maladies Infectieuses et Pharmacologie Anti-Infectieuse (CEMIPAI), CNRS UAR 3725, Université de Montpellier, 1919 Route de Mende, CEDEX 05, 34293 Montpellier, France
- Correspondence: (S.L.); (S.K.S.); (G.M.)
| | - S. Kashif Sadiq
- Infection Biology Laboratory, Department of Experimental and Health Sciences (DCEXS), Universitat Pompeu Fabra, Carrer Doctor Aiguader 88, 08003 Barcelona, Spain;
- Molecular and Cellular Modeling Group, Heidelberg Institute for Theoretical Studies (HITS), Schloss-Wolfsbrunnenweg 35, 69118 Heidelberg, Germany
- Genome Biology Unit, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
- Correspondence: (S.L.); (S.K.S.); (G.M.)
| | - Cristina Lorca-Oró
- Infectious Disease & AIDS Research Unit, Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Villaroel 170, 08036 Barcelona, Spain; (C.L.-O.); (S.N.-M.); (T.E.); (N.G.); (X.T.); (M.O.-O.); (J.O.); (J.M.G.)
| | - Laure Dufau
- Biological Adaptation and Ageing (B2A), CNRS UMR 8256 & INSERM ERL U1164, Institut de Biologie Paris-Seine (IBPS), Faculté des Sciences et d’Ingénierie (FSI), Sorbonne Université, 7 Quai St Bernard, CEDEX 05, 75252 Paris, France; (L.D.); (M.R.-R.)
| | - Sara Nieto-Marquez
- Infectious Disease & AIDS Research Unit, Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Villaroel 170, 08036 Barcelona, Spain; (C.L.-O.); (S.N.-M.); (T.E.); (N.G.); (X.T.); (M.O.-O.); (J.O.); (J.M.G.)
| | - Tuixent Escribà
- Infectious Disease & AIDS Research Unit, Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Villaroel 170, 08036 Barcelona, Spain; (C.L.-O.); (S.N.-M.); (T.E.); (N.G.); (X.T.); (M.O.-O.); (J.O.); (J.M.G.)
| | - Natalia Gabrielli
- Infectious Disease & AIDS Research Unit, Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Villaroel 170, 08036 Barcelona, Spain; (C.L.-O.); (S.N.-M.); (T.E.); (N.G.); (X.T.); (M.O.-O.); (J.O.); (J.M.G.)
| | - Xiao Tan
- Infectious Disease & AIDS Research Unit, Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Villaroel 170, 08036 Barcelona, Spain; (C.L.-O.); (S.N.-M.); (T.E.); (N.G.); (X.T.); (M.O.-O.); (J.O.); (J.M.G.)
- Biological Adaptation and Ageing (B2A), CNRS UMR 8256 & INSERM ERL U1164, Institut de Biologie Paris-Seine (IBPS), Faculté des Sciences et d’Ingénierie (FSI), Sorbonne Université, 7 Quai St Bernard, CEDEX 05, 75252 Paris, France; (L.D.); (M.R.-R.)
| | - Mohamed Ouizougun-Oubari
- Infectious Disease & AIDS Research Unit, Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Villaroel 170, 08036 Barcelona, Spain; (C.L.-O.); (S.N.-M.); (T.E.); (N.G.); (X.T.); (M.O.-O.); (J.O.); (J.M.G.)
| | - Josephine Okoronkwo
- Infectious Disease & AIDS Research Unit, Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Villaroel 170, 08036 Barcelona, Spain; (C.L.-O.); (S.N.-M.); (T.E.); (N.G.); (X.T.); (M.O.-O.); (J.O.); (J.M.G.)
| | - Michèle Reboud-Ravaux
- Biological Adaptation and Ageing (B2A), CNRS UMR 8256 & INSERM ERL U1164, Institut de Biologie Paris-Seine (IBPS), Faculté des Sciences et d’Ingénierie (FSI), Sorbonne Université, 7 Quai St Bernard, CEDEX 05, 75252 Paris, France; (L.D.); (M.R.-R.)
| | - José Maria Gatell
- Infectious Disease & AIDS Research Unit, Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Villaroel 170, 08036 Barcelona, Spain; (C.L.-O.); (S.N.-M.); (T.E.); (N.G.); (X.T.); (M.O.-O.); (J.O.); (J.M.G.)
- Facultat de Medicina y Ciencias de la Salud, Universitat de Barcelona, Carrer de Casanova 143, 08036 Barcelona, Spain
| | - Roland Marquet
- Architecture et Réactivité de l’ARN, CNRS UPR 9002, Université de Strasbourg, 2 Allée Conrad Roentgen, 67000 Strasbourg, France; (R.M.); (J.-C.P.)
| | - Jean-Christophe Paillart
- Architecture et Réactivité de l’ARN, CNRS UPR 9002, Université de Strasbourg, 2 Allée Conrad Roentgen, 67000 Strasbourg, France; (R.M.); (J.-C.P.)
| | - Andreas Meyerhans
- Infection Biology Laboratory, Department of Experimental and Health Sciences (DCEXS), Universitat Pompeu Fabra, Carrer Doctor Aiguader 88, 08003 Barcelona, Spain;
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Passeig de Lluís Companys 23, 08010 Barcelona, Spain
| | - Carine Tisné
- Expression Génétique Microbienne, CNRS UMR 8261, Institut de Biologie Physico-Chimique (IBPC), Université de Paris, 13 Rue Pierre et Marie Curie, 75005 Paris, France;
| | - Robert J. Gorelick
- AIDS and Cancer Virus Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21701, USA;
| | - Gilles Mirambeau
- Infectious Disease & AIDS Research Unit, Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Villaroel 170, 08036 Barcelona, Spain; (C.L.-O.); (S.N.-M.); (T.E.); (N.G.); (X.T.); (M.O.-O.); (J.O.); (J.M.G.)
- Biologie Intégrative des Organismes Marins (BIOM), CNRS UMR 7232, Observatoire Océanologique de Banyuls (OOB), Faculté des Sciences et d’Ingénierie (FSI), Sorbonne Université, 1 Avenue Pierre Fabre, 66650 Banyuls-sur-Mer, France
- Correspondence: (S.L.); (S.K.S.); (G.M.)
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3
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Jiang K, Humbert N, K K S, Rouzina I, Mely Y, Westerlund F. The HIV-1 nucleocapsid chaperone protein forms locally compacted globules on long double-stranded DNA. Nucleic Acids Res 2021; 49:4550-4563. [PMID: 33872352 PMCID: PMC8096146 DOI: 10.1093/nar/gkab236] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Revised: 03/09/2021] [Accepted: 03/22/2021] [Indexed: 01/14/2023] Open
Abstract
The nucleocapsid (NC) protein plays key roles in Human Immunodeficiency Virus 1 (HIV-1) replication, notably by condensing and protecting the viral RNA genome and by chaperoning its reverse transcription into double-stranded DNA (dsDNA). Recent findings suggest that integration of viral dsDNA into the host genome, and hence productive infection, is linked to a small subpopulation of viral complexes where reverse transcription was completed within the intact capsid. Therefore, the synthesized dsDNA has to be tightly compacted, most likely by NC, to prevent breaking of the capsid in these complexes. To investigate NC’s ability to compact viral dsDNA, we here characterize the compaction of single dsDNA molecules under unsaturated NC binding conditions using nanofluidic channels. Compaction is shown to result from accumulation of NC at one or few compaction sites, which leads to small dsDNA condensates. NC preferentially initiates compaction at flexible regions along the dsDNA, such as AT-rich regions and DNA ends. Upon further NC binding, these condensates develop into a globular state containing the whole dsDNA molecule. These findings support NC’s role in viral dsDNA compaction within the mature HIV-1 capsid and suggest a possible scenario for the gradual dsDNA decondensation upon capsid uncoating and NC loss.
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Affiliation(s)
- Kai Jiang
- Division of Chemical Biology, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg SE 412 96, Sweden
| | - Nicolas Humbert
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Université de Strasbourg, Faculté de Pharmacie, Illkirch F 67401, France
| | - Sriram K K
- Division of Chemical Biology, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg SE 412 96, Sweden
| | - Ioulia Rouzina
- Department of Chemistry and Biochemistry, The Ohio State University, Center for Retroviral Research, and Center for RNA Biology, Columbus, OH 43210, USA
| | - Yves Mely
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Université de Strasbourg, Faculté de Pharmacie, Illkirch F 67401, France
| | - Fredrik Westerlund
- Division of Chemical Biology, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg SE 412 96, Sweden
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4
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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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5
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Mouhand A, Pasi M, Catala M, Zargarian L, Belfetmi A, Barraud P, Mauffret O, Tisné C. Overview of the Nucleic-Acid Binding Properties of the HIV-1 Nucleocapsid Protein in Its Different Maturation States. Viruses 2020; 12:v12101109. [PMID: 33003650 PMCID: PMC7601788 DOI: 10.3390/v12101109] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 09/23/2020] [Accepted: 09/26/2020] [Indexed: 12/17/2022] Open
Abstract
HIV-1 Gag polyprotein orchestrates the assembly of viral particles. Its C-terminus consists of the nucleocapsid (NC) domain that interacts with nucleic acids, and p1 and p6, two unstructured regions, p6 containing the motifs to bind ALIX, the cellular ESCRT factor TSG101 and the viral protein Vpr. The processing of Gag by the viral protease subsequently liberates NCp15 (NC-p1-p6), NCp9 (NC-p1) and NCp7, NCp7 displaying the optimal chaperone activity of nucleic acids. This review focuses on the nucleic acid binding properties of the NC domain in the different maturation states during the HIV-1 viral cycle.
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Affiliation(s)
- Assia Mouhand
- Expression Génétique Microbienne, UMR 8261, CNRS, Université de Paris, Institut de Biologie Physico-Chimique (IBPC), 75005 Paris, France; (A.M.); (M.C.); (P.B.)
| | - Marco Pasi
- Laboratoire de Biologie et de Pharmacologie Appliquée (LBPA), UMR 8113 CNRS, Institut D’Alembert, École Normale Supérieure Paris-Saclay, Université Paris-Saclay, 4, Avenue des Sciences, 91190 Gif sur Yvette, France; (M.P.); (L.Z.); (A.B.)
| | - Marjorie Catala
- Expression Génétique Microbienne, UMR 8261, CNRS, Université de Paris, Institut de Biologie Physico-Chimique (IBPC), 75005 Paris, France; (A.M.); (M.C.); (P.B.)
| | - Loussiné Zargarian
- Laboratoire de Biologie et de Pharmacologie Appliquée (LBPA), UMR 8113 CNRS, Institut D’Alembert, École Normale Supérieure Paris-Saclay, Université Paris-Saclay, 4, Avenue des Sciences, 91190 Gif sur Yvette, France; (M.P.); (L.Z.); (A.B.)
| | - Anissa Belfetmi
- Laboratoire de Biologie et de Pharmacologie Appliquée (LBPA), UMR 8113 CNRS, Institut D’Alembert, École Normale Supérieure Paris-Saclay, Université Paris-Saclay, 4, Avenue des Sciences, 91190 Gif sur Yvette, France; (M.P.); (L.Z.); (A.B.)
| | - Pierre Barraud
- Expression Génétique Microbienne, UMR 8261, CNRS, Université de Paris, Institut de Biologie Physico-Chimique (IBPC), 75005 Paris, France; (A.M.); (M.C.); (P.B.)
| | - Olivier Mauffret
- Laboratoire de Biologie et de Pharmacologie Appliquée (LBPA), UMR 8113 CNRS, Institut D’Alembert, École Normale Supérieure Paris-Saclay, Université Paris-Saclay, 4, Avenue des Sciences, 91190 Gif sur Yvette, France; (M.P.); (L.Z.); (A.B.)
- Correspondence: (O.M.); (C.T.)
| | - Carine Tisné
- Expression Génétique Microbienne, UMR 8261, CNRS, Université de Paris, Institut de Biologie Physico-Chimique (IBPC), 75005 Paris, France; (A.M.); (M.C.); (P.B.)
- Correspondence: (O.M.); (C.T.)
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6
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How HIV-1 Gag Manipulates Its Host Cell Proteins: A Focus on Interactors of the Nucleocapsid Domain. Viruses 2020; 12:v12080888. [PMID: 32823718 PMCID: PMC7471995 DOI: 10.3390/v12080888] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 08/06/2020] [Accepted: 08/10/2020] [Indexed: 12/27/2022] Open
Abstract
The human immunodeficiency virus (HIV-1) polyprotein Gag (Group-specific antigen) plays a central role in controlling the late phase of the viral lifecycle. Considered to be only a scaffolding protein for a long time, the structural protein Gag plays determinate and specific roles in HIV-1 replication. Indeed, via its different domains, Gag orchestrates the specific encapsidation of the genomic RNA, drives the formation of the viral particle by its auto-assembly (multimerization), binds multiple viral proteins, and interacts with a large number of cellular proteins that are needed for its functions from its translation location to the plasma membrane, where newly formed virions are released. Here, we review the interactions between HIV-1 Gag and 66 cellular proteins. Notably, we describe the techniques used to evidence these interactions, the different domains of Gag involved, and the implications of these interactions in the HIV-1 replication cycle. In the final part, we focus on the interactions involving the highly conserved nucleocapsid (NC) domain of Gag and detail the functions of the NC interactants along the viral lifecycle.
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Wan Q, Song D, Li H, He ML. Stress proteins: the biological functions in virus infection, present and challenges for target-based antiviral drug development. Signal Transduct Target Ther 2020; 5:125. [PMID: 32661235 PMCID: PMC7356129 DOI: 10.1038/s41392-020-00233-4] [Citation(s) in RCA: 68] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 05/26/2020] [Accepted: 06/13/2020] [Indexed: 02/06/2023] Open
Abstract
Stress proteins (SPs) including heat-shock proteins (HSPs), RNA chaperones, and ER associated stress proteins are molecular chaperones essential for cellular homeostasis. The major functions of HSPs include chaperoning misfolded or unfolded polypeptides, protecting cells from toxic stress, and presenting immune and inflammatory cytokines. Regarded as a double-edged sword, HSPs also cooperate with numerous viruses and cancer cells to promote their survival. RNA chaperones are a group of heterogeneous nuclear ribonucleoproteins (hnRNPs), which are essential factors for manipulating both the functions and metabolisms of pre-mRNAs/hnRNAs transcribed by RNA polymerase II. hnRNPs involve in a large number of cellular processes, including chromatin remodelling, transcription regulation, RNP assembly and stabilization, RNA export, virus replication, histone-like nucleoid structuring, and even intracellular immunity. Dysregulation of stress proteins is associated with many human diseases including human cancer, cardiovascular diseases, neurodegenerative diseases (e.g., Parkinson’s diseases, Alzheimer disease), stroke and infectious diseases. In this review, we summarized the biologic function of stress proteins, and current progress on their mechanisms related to virus reproduction and diseases caused by virus infections. As SPs also attract a great interest as potential antiviral targets (e.g., COVID-19), we also discuss the present progress and challenges in this area of HSP-based drug development, as well as with compounds already under clinical evaluation.
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Affiliation(s)
- Qianya Wan
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon, Hong Kong, China
| | - Dan Song
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon, Hong Kong, China
| | - Huangcan Li
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon, Hong Kong, China
| | - Ming-Liang He
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon, Hong Kong, China. .,CityU Shenzhen Research Institute, Shenzhen, China.
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Ciaco S, Humbert N, Real E, Boudier C, Francesconi O, Roelens S, Nativi C, Seguin-Devaux C, Mori M, Mély Y. A Class of Potent Inhibitors of the HIV-1 Nucleocapsid Protein Based on Aminopyrrolic Scaffolds. ACS Med Chem Lett 2020; 11:698-705. [PMID: 32435373 DOI: 10.1021/acsmedchemlett.9b00558] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Accepted: 01/27/2020] [Indexed: 01/08/2023] Open
Abstract
The HIV-1 nucleocapsid protein 7 (NC) is a potential target for effective antiretroviral therapy due to its central role in virus replication, mainly linked to nucleic acid (NA) chaperone activity, and low susceptibility to drug resistance. By screening a compounds library, we identified the aminopyrrolic compound CN14_17, a known carbohydrate binding agent, that inhibits the NC chaperone activity in the low micromolar range. Different from most of available NC inhibitors, CN14_17 fully prevents the NC-induced annealing of complementary NA sequences. Using fluorescence assays and isothermal titration calorimetry, we found that CN14_17 competes with NC for the binding to NAs, preferentially targeting single-stranded sequences. Molecular dynamics simulations confirmed that binding to cTAR occurs preferably within the guanosine-rich single stranded sequence. Finally, CN14_17 exhibited antiretroviral activity in the low micromolar range, although with a moderate therapeutic index. Overall, CN14_17 might be the progenitor of a new promising class of NC inhibitors.
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Affiliation(s)
- Stefano Ciaco
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Faculté de Pharmacie, Université de Strasbourg, 74 route du Rhin, 67401 Illkirch, France
- Department of Biotechnology, Chemistry and Pharmacy, Department of Excellence 2018-2022 Università degli Studi di Siena, via Aldo Moro 2, I-53019 Siena, Italy
| | - Nicolas Humbert
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Faculté de Pharmacie, Université de Strasbourg, 74 route du Rhin, 67401 Illkirch, France
| | - Eléonore Real
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Faculté de Pharmacie, Université de Strasbourg, 74 route du Rhin, 67401 Illkirch, France
| | - Christian Boudier
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Faculté de Pharmacie, Université de Strasbourg, 74 route du Rhin, 67401 Illkirch, France
| | - Oscar Francesconi
- Dipartimento di Chimica “Ugo Schiff” and INSTM, University of Florence, via della Lastruccia, 3-13, 50019 Sesto Fiorentino, Florence, Italy
| | - Stefano Roelens
- Dipartimento di Chimica “Ugo Schiff” and INSTM, University of Florence, via della Lastruccia, 3-13, 50019 Sesto Fiorentino, Florence, Italy
| | - Cristina Nativi
- Dipartimento di Chimica “Ugo Schiff” and INSTM, University of Florence, via della Lastruccia, 3-13, 50019 Sesto Fiorentino, Florence, Italy
| | - Carole Seguin-Devaux
- Department of Infection and Immunity, Luxembourg Institute of Health, 29 rue Henri Koch, L-4354 Esch-sur-Alzette, Luxembourg
| | - Mattia Mori
- Department of Biotechnology, Chemistry and Pharmacy, Department of Excellence 2018-2022 Università degli Studi di Siena, via Aldo Moro 2, I-53019 Siena, Italy
| | - Yves Mély
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Faculté de Pharmacie, Université de Strasbourg, 74 route du Rhin, 67401 Illkirch, France
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9
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Significant Differences in RNA Structure Destabilization by HIV-1 GagDp6 and NCp7 Proteins. Viruses 2020; 12:v12050484. [PMID: 32344834 PMCID: PMC7290599 DOI: 10.3390/v12050484] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 04/15/2020] [Accepted: 04/21/2020] [Indexed: 01/12/2023] Open
Abstract
Retroviral nucleocapsid (NC) proteins are nucleic acid chaperones that play distinct roles in the viral life cycle. During reverse transcription, HIV-1 NC facilitates the rearrangement of nucleic acid secondary structures, allowing the transactivation response (TAR) RNA hairpin to be transiently destabilized and annealed to a complementary RNA hairpin. In contrast, during viral assembly, NC, as a domain of the group-specific antigen (Gag) polyprotein, binds the genomic RNA and facilitates packaging into new virions. It is not clear how the same protein, alone or as part of Gag, performs such different RNA binding functions in the viral life cycle. By combining single-molecule optical tweezers measurements with a quantitative mfold-based model, we characterize the equilibrium stability and unfolding barrier for TAR RNA. Comparing measured results with a model of discrete protein binding allows us to localize affected binding sites, in addition to quantifying hairpin stability. We find that, while both NCp7 and Gag∆p6 destabilize the TAR hairpin, Gag∆p6 binding is localized to two sites in the stem, while NCp7 targets sites near the top loop. Unlike Gag∆p6, NCp7 destabilizes this loop, shifting the location of the reaction barrier toward the folded state and increasing the natural rate of hairpin opening by ~104. Thus, our results explain why Gag cleavage and NC release is an essential prerequisite for reverse transcription within the virion.
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10
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Annealing of ssDNA and compaction of dsDNA by the HIV-1 nucleocapsid and Gag proteins visualized using nanofluidic channels. Q Rev Biophys 2019; 52:e2. [DOI: 10.1017/s0033583518000124] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Abstract
The nucleocapsid protein NC is a crucial component in the human immunodeficiency virus type 1 life cycle. It functions both in its processed mature form and as part of the polyprotein Gag that plays a key role in the formation of new viruses. NC can protect nucleic acids (NAs) from degradation by compacting them to a dense coil. Moreover, through its NA chaperone activity, NC can also promote the most stable conformation of NAs. Here, we explore the balance between these activities for NC and Gag by confining DNA–protein complexes in nanochannels. The chaperone activity is visualized as concatemerization and circularization of long DNA via annealing of short single-stranded DNA overhangs. The first ten amino acids of NC are important for the chaperone activity that is almost completely absent for Gag. Gag condenses DNA more efficiently than mature NC, suggesting that additional residues of Gag are involved. Importantly, this is the first single DNA molecule study of full-length Gag and we reveal important differences to the truncated Δ-p6 Gag that has been used before. In addition, the study also highlights how nanochannels can be used to study reactions on ends of long single DNA molecules, which is not trivial with competing single DNA molecule techniques.
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11
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Abstract
RNA-binding proteins chaperone the biological functions of noncoding RNA by reducing RNA misfolding, improving matchmaking between regulatory RNA and targets, and exerting quality control over RNP biogenesis. Recent studies of Escherichia coli CspA, HIV NCp, and E. coli Hfq are beginning to show how RNA-binding proteins remodel RNA structures. These different protein families use common strategies for disrupting or annealing RNA double helices, which can be used to understand the mechanisms by which proteins chaperone RNA-dependent regulation in bacteria.
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12
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Sholokh M, Sharma R, Grytsyk N, Zaghzi L, Postupalenko VY, Dziuba D, Barthes NPF, Michel BY, Boudier C, Zaporozhets OA, Tor Y, Burger A, Mély Y. Environmentally Sensitive Fluorescent Nucleoside Analogues for Surveying Dynamic Interconversions of Nucleic Acid Structures. Chemistry 2018; 24:13850-13861. [PMID: 29989220 DOI: 10.1002/chem.201802297] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Indexed: 11/12/2022]
Abstract
Nucleic acids are characterized by a variety of dynamically interconverting structures that play a major role in transcriptional and translational regulation as well as recombination and repair. To monitor these interconversions, Förster resonance energy transfer (FRET)-based techniques can be used, but require two fluorophores that are typically large and can alter the DNA/RNA structure and protein binding. Additionally, events that do not alter the donor/acceptor distance and/or angular relationship are frequently left undetected. A more benign approach relies on fluorescent nucleobases that can substitute their native counterparts with minimal perturbation, such as the recently developed 2-thienyl-3-hydroxychromone (3HCnt) and thienoguanosine (th G). To demonstrate the potency of 3HCnt and th G in deciphering interconversion mechanisms, we used the conversion of the (-)DNA copy of the HIV-1 primer binding site (-)PBS stem-loop into (+)/(-)PBS duplex, as a model system. When incorporated into the (-)PBS loop, the two probes were found to be highly sensitive to the individual steps both in the absence and the presence of a nucleic acid chaperone, providing the first complete mechanistic description of this critical process in HIV-1 replication. The combination of the two distinct probes appears to be instrumental for characterizing structural transitions of nucleic acids under various stimuli.
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Affiliation(s)
- Marianna Sholokh
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Université de Strasbourg, Faculté de Pharmacie, 74 Route du Rhin, 67401, Illkirch, France.,Department of Chemistry, Kyiv National Taras Shevchenko University, 60 Volodymyrska street, 01033, Kyiv, Ukraine
| | - Rajhans Sharma
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Université de Strasbourg, Faculté de Pharmacie, 74 Route du Rhin, 67401, Illkirch, France
| | - Natalia Grytsyk
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Université de Strasbourg, Faculté de Pharmacie, 74 Route du Rhin, 67401, Illkirch, France
| | - Lyes Zaghzi
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Université de Strasbourg, Faculté de Pharmacie, 74 Route du Rhin, 67401, Illkirch, France
| | - Viktoriia Y Postupalenko
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Université de Strasbourg, Faculté de Pharmacie, 74 Route du Rhin, 67401, Illkirch, France
| | - Dmytro Dziuba
- Institut de Chimie de Nice, UMR 7272 CNRS, Université Côte d'Azur, Parc Valrose, 06108, Nice, France
| | - Nicolas P F Barthes
- Institut de Chimie de Nice, UMR 7272 CNRS, Université Côte d'Azur, Parc Valrose, 06108, Nice, France
| | - Benoît Y Michel
- Institut de Chimie de Nice, UMR 7272 CNRS, Université Côte d'Azur, Parc Valrose, 06108, Nice, France
| | - Christian Boudier
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Université de Strasbourg, Faculté de Pharmacie, 74 Route du Rhin, 67401, Illkirch, France
| | - Olga A Zaporozhets
- Department of Chemistry, Kyiv National Taras Shevchenko University, 60 Volodymyrska street, 01033, Kyiv, Ukraine
| | - Yitzhak Tor
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0358, USA
| | - Alain Burger
- Institut de Chimie de Nice, UMR 7272 CNRS, Université Côte d'Azur, Parc Valrose, 06108, Nice, France
| | - Yves Mély
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Université de Strasbourg, Faculté de Pharmacie, 74 Route du Rhin, 67401, Illkirch, France
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13
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René B, Mauffret O, Fossé P. Retroviral nucleocapsid proteins and DNA strand transfers. BIOCHIMIE OPEN 2018; 7:10-25. [PMID: 30109196 PMCID: PMC6088434 DOI: 10.1016/j.biopen.2018.07.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 07/08/2018] [Indexed: 12/12/2022]
Abstract
An infectious retroviral particle contains 1000-1500 molecules of the nucleocapsid protein (NC) that cover the diploid RNA genome. NC is a small zinc finger protein that possesses nucleic acid chaperone activity that enables NC to rearrange DNA and RNA molecules into the most thermodynamically stable structures usually those containing the maximum number of base pairs. Thanks to the chaperone activity, NC plays an essential role in reverse transcription of the retroviral genome by facilitating the strand transfer reactions of this process. In addition, these reactions are involved in recombination events that can generate multiple drug resistance mutations in the presence of anti-HIV-1 drugs. The strand transfer reactions rely on base pairing of folded DNA/RNA structures. The molecular mechanisms responsible for NC-mediated strand transfer reactions are presented and discussed in this review. Antiretroviral strategies targeting the NC-mediated strand transfer events are also discussed.
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Affiliation(s)
- Brigitte René
- LBPA, ENS Paris-Saclay, UMR 8113, CNRS, Université Paris-Saclay, 61 Avenue du Président Wilson, 94235, Cachan, France
| | - Olivier Mauffret
- LBPA, ENS Paris-Saclay, UMR 8113, CNRS, Université Paris-Saclay, 61 Avenue du Président Wilson, 94235, Cachan, France
| | - Philippe Fossé
- LBPA, ENS Paris-Saclay, UMR 8113, CNRS, Université Paris-Saclay, 61 Avenue du Président Wilson, 94235, Cachan, France
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14
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Shvadchak V, Zgheib S, Basta B, Humbert N, Langedijk J, Morris MC, Ciaco S, Maskri O, Darlix JL, Mauffret O, Fossé P, Réal E, Mély Y. Rationally Designed Peptides as Efficient Inhibitors of Nucleic Acid Chaperone Activity of HIV-1 Nucleocapsid Protein. Biochemistry 2018; 57:4562-4573. [PMID: 30019894 DOI: 10.1021/acs.biochem.8b00527] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Due to its essential roles in the viral replication cycle and to its highly conserved sequence, the nucleocapsid protein (NCp7) of the human immunodeficiency virus type 1 is a target of choice for inhibiting replication of the virus. Most NCp7 inhibitors identified so far are small molecules. A small number of short peptides also act as NCp7 inhibitors by competing with its nucleic acid (NA) binding and chaperone activities but exhibit antiviral activity only at relatively high concentrations. In this work, in order to obtain more potent NCp7 competitors, we designed a library of longer peptides (10-17 amino acids) whose sequences include most of the NCp7 structural determinants responsible for its specific NA binding and destabilizing activities. Using an in vitro assay, the most active peptide (pE) was found to inhibit the NCp7 destabilizing activity, with a 50% inhibitory concentration in the nanomolar range, by competing with NCp7 for binding to its NA substrates. Formulated with a cell-penetrating peptide (CPP), pE was found to accumulate into HeLa cells, with low cytotoxicity. However, either formulated with a CPP or overexpressed in cells, pE did not show any antiviral activity. In vitro competition experiments revealed that its poor antiviral activity may be partly due to its sequestration by cellular RNAs. The selected peptide pE therefore appears to be a useful tool for investigating NCp7 properties and functions in vitro, but further work will be needed to design pE-derived peptides with antiviral activity.
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Affiliation(s)
- Volodymyr Shvadchak
- Laboratory of Bioimaging and Pathologies, UMR 7021 CNRS , Université de Strasbourg , 74 route du Rhin , 67401 Illkirch , France
| | - Sarwat Zgheib
- Laboratory of Bioimaging and Pathologies, UMR 7021 CNRS , Université de Strasbourg , 74 route du Rhin , 67401 Illkirch , France
| | - Beata Basta
- Laboratory of Bioimaging and Pathologies, UMR 7021 CNRS , Université de Strasbourg , 74 route du Rhin , 67401 Illkirch , France
| | - Nicolas Humbert
- Laboratory of Bioimaging and Pathologies, UMR 7021 CNRS , Université de Strasbourg , 74 route du Rhin , 67401 Illkirch , France
| | | | - May C Morris
- Institut des biomolécules Max Mousseron, CNRS, UMR 5247 , Université de Montpellier Faculté de Pharmacie , 15 av Charles Flahault 34093 Montpellier , France
| | - Stefano Ciaco
- Laboratory of Bioimaging and Pathologies, UMR 7021 CNRS , Université de Strasbourg , 74 route du Rhin , 67401 Illkirch , France
| | - Ouerdia Maskri
- LBPA, ENS Paris Saclay, CNRS , Université Paris-Saclay , 94235 , Cachan Cedex , France
| | - Jean-Luc Darlix
- Laboratory of Bioimaging and Pathologies, UMR 7021 CNRS , Université de Strasbourg , 74 route du Rhin , 67401 Illkirch , France
| | - Olivier Mauffret
- LBPA, ENS Paris Saclay, CNRS , Université Paris-Saclay , 94235 , Cachan Cedex , France
| | - Philippe Fossé
- LBPA, ENS Paris Saclay, CNRS , Université Paris-Saclay , 94235 , Cachan Cedex , France
| | - Eléonore Réal
- Laboratory of Bioimaging and Pathologies, UMR 7021 CNRS , Université de Strasbourg , 74 route du Rhin , 67401 Illkirch , France
| | - Yves Mély
- Laboratory of Bioimaging and Pathologies, UMR 7021 CNRS , Université de Strasbourg , 74 route du Rhin , 67401 Illkirch , France
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15
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Ren W, Ji D, Xu X. Metal cofactor modulated folding and target recognition of HIV-1 NCp7. PLoS One 2018; 13:e0196662. [PMID: 29715277 PMCID: PMC5929515 DOI: 10.1371/journal.pone.0196662] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Accepted: 04/17/2018] [Indexed: 01/01/2023] Open
Abstract
The HIV-1 nucleocapsid 7 (NCp7) plays crucial roles in multiple stages of HIV-1 life cycle, and its biological functions rely on the binding of zinc ions. Understanding the molecular mechanism of how the zinc ions modulate the conformational dynamics and functions of the NCp7 is essential for the drug development and HIV-1 treatment. In this work, using a structure-based coarse-grained model, we studied the effects of zinc cofactors on the folding and target RNA(SL3) recognition of the NCp7 by molecular dynamics simulations. After reproducing some key properties of the zinc binding and folding of the NCp7 observed in previous experiments, our simulations revealed several interesting features in the metal ion modulated folding and target recognition. Firstly, we showed that the zinc binding makes the folding transition states of the two zinc fingers less structured, which is in line with the Hammond effect observed typically in mutation, temperature or denaturant induced perturbations to protein structure and stability. Secondly, We showed that there exists mutual interplay between the zinc ion binding and NCp7-target recognition. Binding of zinc ions enhances the affinity between the NCp7 and the target RNA, whereas the formation of the NCp7-RNA complex reshapes the intrinsic energy landscape of the NCp7 and increases the stability and zinc affinity of the two zinc fingers. Thirdly, by characterizing the effects of salt concentrations on the target RNA recognition, we showed that the NCp7 achieves optimal balance between the affinity and binding kinetics near the physiologically relevant salt concentrations. In addition, the effects of zinc binding on the inter-domain conformational flexibility and folding cooperativity of the NCp7 were also discussed.
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Affiliation(s)
- Weitong Ren
- School of Physics, Nanjing University, Nanjing 210093, China
| | - Dongqing Ji
- School of Physics, Nanjing University, Nanjing 210093, China
| | - Xiulian Xu
- School of Physical Science and Technology, Yangzhou University, Yangzhou 225002, China
- * E-mail:
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16
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Naufer MN, Furano AV, Williams MC. Protein-nucleic acid interactions of LINE-1 ORF1p. Semin Cell Dev Biol 2018; 86:140-149. [PMID: 29596909 PMCID: PMC6428221 DOI: 10.1016/j.semcdb.2018.03.019] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Revised: 03/19/2018] [Accepted: 03/23/2018] [Indexed: 11/03/2022]
Abstract
Long interspersed nuclear element 1 (LINE-1 or L1) is the dominant retrotransposon in mammalian genomes. L1 encodes two proteins ORF1p and ORF2p that are required for retrotransposition. ORF2p functions as the replicase. ORF1p is a coiled coil-mediated trimeric, high affinity RNA binding protein that packages its full- length coding transcript into an ORF2p-containing ribonucleoprotein (RNP) complex, the retrotransposition intermediate. ORF1p also is a nucleic acid chaperone that presumably facilitates the proposed nucleic acid remodeling steps involved in retrotransposition. Although detailed mechanistic understanding of ORF1p function in this process is lacking, recent studies showed that the rate at which ORF1p can form stable nucleic acid-bound oligomers in vitro is positively correlated with formation of an active L1 RNP as assayed in vivo using a cell culture-based retrotransposition assay. This rate was sensitive to minor amino acid changes in the coiled coil domain, which had no effect on nucleic acid chaperone activity. Additional studies linking the complex nucleic acid binding properties to the conformational changes of the protein are needed to understand how ORF1p facilitates retrotransposition.
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Affiliation(s)
- M Nabuan Naufer
- Northeastern University, Department of Physics, Boston, MA 02115, USA
| | - Anthony V Furano
- The Laboratory of Molecular and Cellular Biology, NIDDK, NIH, Bethesda, MD 20892, USA
| | - Mark C Williams
- Northeastern University, Department of Physics, Boston, MA 02115, USA.
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17
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Mori M, Kovalenko L, Malancona S, Saladini F, De Forni D, Pires M, Humbert N, Real E, Botzanowski T, Cianférani S, Giannini A, Dasso Lang MC, Cugia G, Poddesu B, Lori F, Zazzi M, Harper S, Summa V, Mely Y, Botta M. Structure-Based Identification of HIV-1 Nucleocapsid Protein Inhibitors Active against Wild-Type and Drug-Resistant HIV-1 Strains. ACS Chem Biol 2018; 13:253-266. [PMID: 29235845 DOI: 10.1021/acschembio.7b00907] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
HIV/AIDS is still one of the leading causes of death worldwide. Current drugs that target the canonical steps of the HIV-1 life cycle are efficient in blocking viral replication but are unable to eradicate HIV-1 from infected patients. Moreover, drug resistance (DR) is often associated with the clinical use of these molecules, thus raising the need for novel drug candidates as well as novel putative drug targets. In this respect, pharmacological inhibition of the highly conserved and multifunctional nucleocapsid protein (NC) of HIV-1 is considered a promising alternative to current drugs, particularly to overcome DR. Here, using a multidisciplinary approach combining in silico screening, fluorescence-based molecular assays, and cellular antiviral assays, we identified nordihydroguaiaretic acid (6), as a novel natural product inhibitor of NC. By using NMR, mass spectrometry, fluorescence spectroscopy, and molecular modeling, 6 was found to act through a dual mechanism of action never highlighted before for NC inhibitors (NCIs). First, the molecule recognizes and binds NC noncovalently, which results in the inhibition of the nucleic acid chaperone properties of NC. In a second step, chemical oxidation of 6 induces a potent chemical inactivation of the protein. Overall, 6 inhibits NC and the replication of wild-type and drug-resistant HIV-1 strains in the low micromolar range with moderate cytotoxicity that makes it a profitable tool compound as well as a good starting point for the development of pharmacologically relevant NCIs.
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Affiliation(s)
- Mattia Mori
- Department
of Biotechnology, Chemistry and Pharmacy, University of Siena, via Aldo Moro 2, 53100 Siena, Italy
| | - Lesia Kovalenko
- Laboratoire
de Biophotonique et Pharmacologie, UMR 7213, Faculté de Pharmacie, Université de Strasbourg, CNRS, 74 Route du Rhin, 67401 Illkirch, France
- Department
of Chemistry, Kyiv National Taras Shevchenko University, 01033 Kyiv, Ukraine
| | - Savina Malancona
- IRBM Science Park S.p.A., Via Pontina Km 30.600, 00071 Pomezia (RM), Italy
| | - Francesco Saladini
- Department
of Medical Biotechnologies, University of Siena, Viale Mario Bracci,
16, 50100 Siena, Italy
| | | | - Manuel Pires
- Laboratoire
de Biophotonique et Pharmacologie, UMR 7213, Faculté de Pharmacie, Université de Strasbourg, CNRS, 74 Route du Rhin, 67401 Illkirch, France
| | - Nicolas Humbert
- Laboratoire
de Biophotonique et Pharmacologie, UMR 7213, Faculté de Pharmacie, Université de Strasbourg, CNRS, 74 Route du Rhin, 67401 Illkirch, France
| | - Eleonore Real
- Laboratoire
de Biophotonique et Pharmacologie, UMR 7213, Faculté de Pharmacie, Université de Strasbourg, CNRS, 74 Route du Rhin, 67401 Illkirch, France
| | - Thomas Botzanowski
- Laboratoire
de Spectrométrie de Masse BioOrganique, Université de Strasbourg, CNRS, IPHC UMR 7178, F-67000 Strasbourg, France
| | - Sarah Cianférani
- Laboratoire
de Spectrométrie de Masse BioOrganique, Université de Strasbourg, CNRS, IPHC UMR 7178, F-67000 Strasbourg, France
| | - Alessia Giannini
- Department
of Medical Biotechnologies, University of Siena, Viale Mario Bracci,
16, 50100 Siena, Italy
| | - Maria Chiara Dasso Lang
- Department
of Biotechnology, Chemistry and Pharmacy, University of Siena, via Aldo Moro 2, 53100 Siena, Italy
| | - Giulia Cugia
- ViroStatics S.r.l, Viale Umberto
I 46, 07100 Sassari, Italy
| | | | - Franco Lori
- ViroStatics S.r.l, Viale Umberto
I 46, 07100 Sassari, Italy
| | - Maurizio Zazzi
- Department
of Medical Biotechnologies, University of Siena, Viale Mario Bracci,
16, 50100 Siena, Italy
| | - Steven Harper
- IRBM Science Park S.p.A., Via Pontina Km 30.600, 00071 Pomezia (RM), Italy
| | - Vincenzo Summa
- IRBM Science Park S.p.A., Via Pontina Km 30.600, 00071 Pomezia (RM), Italy
| | - Yves Mely
- Laboratoire
de Biophotonique et Pharmacologie, UMR 7213, Faculté de Pharmacie, Université de Strasbourg, CNRS, 74 Route du Rhin, 67401 Illkirch, France
| | - Maurizio Botta
- Department
of Biotechnology, Chemistry and Pharmacy, University of Siena, via Aldo Moro 2, 53100 Siena, Italy
- Sbarro
Institute for Cancer Research and Molecular Medicine, Center for Biotechnology,
College of Science and Technology, Temple University, BioLife Science
Bldg., Suite 333, 1900 N 12th Street, Philadelphia, Pennsylvania 19122, United States
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18
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Iraci N, Tabarrini O, Santi C, Sancineto L. NCp7: targeting a multitask protein for next-generation anti-HIV drug development part 2. Noncovalent inhibitors and nucleic acid binders. Drug Discov Today 2018; 23:687-695. [PMID: 29326078 DOI: 10.1016/j.drudis.2018.01.022] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2017] [Revised: 10/25/2017] [Accepted: 01/04/2018] [Indexed: 02/06/2023]
Abstract
Nucleocapsid protein 7 (NCp7) represents a viable target not yet reached by the currently available antiretrovirals. It is a small and highly basic protein, which is essential for multiple stages of the viral replicative cycle, with its structure preserved in all viral strains, including clinical isolates. NCp7 can be inhibited covalently, noncovalently and by shielding the nucleic acid (NA) substrates of its chaperone activity. Although covalent NCp7 inhibitors have already been detailed in the first part of this review series, the focus here is based on noncovalent and NA-binder inhibitors and on the analysis of the NCp7 3D structure to deliver fruitful insights for future drug design strategies.
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Affiliation(s)
- Nunzio Iraci
- Department of Pharmacy, University of Salerno, Fisciano, Salerno, Italy
| | - Oriana Tabarrini
- Department of Pharmaceutical Sciences, University of Perugia, Perugia, Italy
| | - Claudio Santi
- Department of Pharmaceutical Sciences, University of Perugia, Perugia, Italy
| | - Luca Sancineto
- Department of Heterorganic Chemistry, Centre of Molecular and Macromulecular Studies, Lodz, Poland.
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19
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Malik O, Khamis H, Rudnizky S, Marx A, Kaplan A. Pausing kinetics dominates strand-displacement polymerization by reverse transcriptase. Nucleic Acids Res 2017; 45:10190-10205. [PMID: 28973474 PMCID: PMC5737391 DOI: 10.1093/nar/gkx720] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Accepted: 08/08/2017] [Indexed: 12/20/2022] Open
Abstract
Reverse transcriptase (RT) catalyzes the conversion of the viral RNA into an integration-competent double-stranded DNA, with a variety of enzymatic activities that include the ability to displace a non-template strand concomitantly with polymerization. Here, using high-resolution optical tweezers to follow the activity of the murine leukemia Virus RT, we show that strand-displacement polymerization is frequently interrupted. Abundant pauses are modulated by the strength of the DNA duplex ∼8 bp ahead, indicating the existence of uncharacterized RT/DNA interactions, and correspond to backtracking of the enzyme, whose recovery is also modulated by the duplex strength. Dissociation and reinitiation events, which induce long periods of inactivity and are likely the rate-limiting step in the synthesis of the genome in vivo, are modulated by the template structure and the viral nucleocapsid protein. Our results emphasize the potential regulatory role of conserved structural motifs, and may provide useful information for the development of potent and specific inhibitors.
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Affiliation(s)
- Omri Malik
- Faculty of Biology, Technion-Israel Institute of Technology, Haifa 32000, Israel.,Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Hadeel Khamis
- Faculty of Biology, Technion-Israel Institute of Technology, Haifa 32000, Israel.,Faculty of Physics, Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Sergei Rudnizky
- Faculty of Biology, Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Ailie Marx
- Faculty of Biology, Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Ariel Kaplan
- Faculty of Biology, Technion-Israel Institute of Technology, Haifa 32000, Israel.,Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa 32000, Israel
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20
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Sancineto L, Iraci N, Tabarrini O, Santi C. NCp7: targeting a multitasking protein for next-generation anti-HIV drug development part 1: covalent inhibitors. Drug Discov Today 2017; 23:260-271. [PMID: 29107765 DOI: 10.1016/j.drudis.2017.10.017] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2017] [Revised: 10/02/2017] [Accepted: 10/17/2017] [Indexed: 11/16/2022]
Abstract
The major internal component of the HIV virion core is the nucleocapsid protein 7 (NCp7), a small, highly basic protein that is essential for multiple stages of the viral replicative cycle, and whose structure is preserved in all viral strains, including clinical isolates from therapy-experienced patients. This key protein is recognised as a potential target for an effective next-generation antiretroviral therapy, because it could offer the possibility to develop broad-spectrum agents that are less prone to select for resistant strains. Here, we provide a comprehensive overview of the covalent NCp7 inhibitors that have emerged over the past 25 years of drug discovery campaigns, emphasising, where possible, their structure-activity relationships (SARs) and pharmacophoric features.
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Affiliation(s)
- Luca Sancineto
- Department of Heterorganic Chemistry, Centre of Molecular and Macromolecular Studies, Lodz, Poland.
| | - Nunzio Iraci
- Department of Pharmacy, University of Salerno, Fisciano, Salerno, Italy
| | - Oriana Tabarrini
- Department of Pharmaceutical Sciences, University of Perugia, Perugia, Italy
| | - Claudio Santi
- Department of Pharmaceutical Sciences, University of Perugia, Perugia, Italy
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21
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Fate of HIV-1 cDNA intermediates during reverse transcription is dictated by transcription initiation site of virus genomic RNA. Sci Rep 2015; 5:17680. [PMID: 26631448 PMCID: PMC4668388 DOI: 10.1038/srep17680] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Accepted: 11/04/2015] [Indexed: 02/07/2023] Open
Abstract
Retroviral reverse transcription is accomplished by sequential strand-transfers of partial cDNA intermediates copied from viral genomic RNA. Here, we revealed an unprecedented role of 5′-end guanosine (G) of HIV-1 genomic RNA for reverse transcription. Based on current consensus for HIV-1 transcription initiation site, HIV-1 transcripts possess a single G at 5′-ends (G1-form). However, we found that HIV-1 transcripts with additional Gs at 5′-ends (G2- and G3-forms) were abundantly expressed in infected cells by using alternative transcription initiation sites. The G2- and G3-forms were also detected in the virus particle, although the G1-form predominated. To address biological impact of the 5′-G number, we generated HIV clone DNA to express the G1-form exclusively by deleting the alternative initiation sites. Virus produced from the clone showed significantly higher strand-transfer of minus strong-stop cDNA (-sscDNA). The in vitro assay using synthetic HIV-1 RNAs revealed that the abortive forms of -sscDNA were abundantly generated from the G3-form RNA, but dramatically reduced from the G1-form. Moreover, the strand-transfer of -sscDNA from the G1-form was prominently stimulated by HIV-1 nucleocapsid. Taken together, our results demonstrated that the 5′-G number that corresponds to HIV-1 transcription initiation site was critical for successful strand-transfer of -sscDNA during reverse transcription.
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22
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Mori M, Kovalenko L, Lyonnais S, Antaki D, Torbett BE, Botta M, Mirambeau G, Mély Y. Nucleocapsid Protein: A Desirable Target for Future Therapies Against HIV-1. Curr Top Microbiol Immunol 2015; 389:53-92. [PMID: 25749978 PMCID: PMC7122173 DOI: 10.1007/82_2015_433] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The currently available anti-HIV-1 therapeutics is highly beneficial to infected patients. However, clinical failures occur as a result of the ability of HIV-1 to rapidly mutate. One approach to overcome drug resistance is to target HIV-1 proteins that are highly conserved among phylogenetically distant viral strains and currently not targeted by available therapies. In this respect, the nucleocapsid (NC) protein, a zinc finger protein, is particularly attractive, as it is highly conserved and plays a central role in virus replication, mainly by interacting with nucleic acids. The compelling rationale for considering NC as a viable drug target is illustrated by the fact that point mutants of this protein lead to noninfectious viruses and by the inability to select viruses resistant to a first generation of anti-NC drugs. In our review, we discuss the most relevant properties and functions of NC, as well as recent developments of small molecules targeting NC. Zinc ejectors show strong antiviral activity, but are endowed with a low therapeutic index due to their lack of specificity, which has resulted in toxicity. Currently, they are mainly being investigated for use as topical microbicides. Greater specificity may be achieved by using non-covalent NC inhibitors (NCIs) targeting the hydrophobic platform at the top of the zinc fingers or key nucleic acid partners of NC. Within the last few years, innovative methodologies have been developed to identify NCIs. Though the antiviral activity of the identified NCIs needs still to be improved, these compounds strongly support the druggability of NC and pave the way for future structure-based design and optimization of efficient NCIs.
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Affiliation(s)
- Mattia Mori
- Dipartimento di Biotecnologie Chimica e Farmacia, Università degli Studi di Siena, via A. Moro 2, 53100, Siena, Italy
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23
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Chen Y, Ma K, Hu T, Jiang B, Xu B, Tian W, Sun JZ, Zhang W. Investigation of the binding modes between AIE-active molecules and dsDNA by single molecule force spectroscopy. NANOSCALE 2015; 7:8939-8945. [PMID: 25920935 DOI: 10.1039/c5nr01247c] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
AIE (aggregation-induced emission)-active molecules hold promise for the labeling of biomolecules as well as living cells. The study of the binding modes of such molecules to biomolecules, such as nucleic acids and proteins, will shed light on a deeper understanding of the mechanisms of molecular interactions and eventually facilitate the design/preparation of new AIE-active bioprobes. Herein, we studied the binding modes of double-stranded DNA (dsDNA) with two types of synthetic AIE-active molecules, namely, tetraphenylethene-derived dicationic compounds (cis-TPEDPy and trans-TPEDPy) and anthracene-derived dicationic compounds (DSAI and DSABr-C6) using single molecule force spectroscopy (SMFS) and circular dichroism (CD) spectroscopy. The experimental data indicate that DSAI can strongly intercalate into DNA base pairs, while DSABr-C6 is unable to intercalate into DNA due to the steric hindrance of the alkyl side chains. Cis-TPEDPy and trans-TPEDPy can also intercalate into DNA base pairs, but the binding shows strong ionic strength dependence. Multiple binding modes of TPEDPy with dsDNA have been discussed. In addition, the electrostatic interaction enhanced intercalation of cis-TPEDPy with dsDNA has also been revealed.
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Affiliation(s)
- Ying Chen
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, 130012, P. R. China.
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24
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Wu H, Wang W, Naiyer N, Fichtenbaum E, Qualley DF, McCauley MJ, Gorelick RJ, Rouzina I, Musier-Forsyth K, Williams MC. Single aromatic residue location alters nucleic acid binding and chaperone function of FIV nucleocapsid protein. Virus Res 2014; 193:39-51. [PMID: 24915282 PMCID: PMC4252577 DOI: 10.1016/j.virusres.2014.06.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Revised: 05/28/2014] [Accepted: 06/02/2014] [Indexed: 10/25/2022]
Abstract
Feline immunodeficiency virus (FIV) is a retrovirus that infects domestic cats, and is an excellent animal model for human immunodeficiency virus type 1 (HIV-1) pathogenesis. The nucleocapsid (NC) protein is critical for replication in both retroviruses. FIV NC has several structural features that differ from HIV-1 NC. While both NC proteins have a single conserved aromatic residue in each of the two zinc fingers, the aromatic residue on the second finger of FIV NC is located on the opposite C-terminal side relative to its location in HIV-1 NC. In addition, whereas HIV-1 NC has a highly charged cationic N-terminal tail and a relatively short C-terminal extension, the opposite is true for FIV NC. To probe the impact of these differences on the nucleic acid (NA) binding and chaperone properties of FIV NC, we carried out ensemble and single-molecule assays with wild-type (WT) and mutant proteins. The ensemble studies show that FIV NC binding to DNA is strongly electrostatic, with a higher effective charge than that observed for HIV-1 NC. The C-terminal basic domain contributes significantly to the NA binding capability of FIV NC. In addition, the non-electrostatic component of DNA binding is much weaker for FIV NC than for HIV-1 NC. Mutation of both aromatic residues in the zinc fingers to Ala (F12A/W44A) further increases the effective charge of FIV NC and reduces its non-electrostatic binding affinity. Interestingly, switching the location of the C-terminal aromatic residue to mimic the HIV-1 NC sequence (N31W/W44A) reduces the effective charge of FIV NC and increases its non-electrostatic binding affinity to values similar to HIV-1 NC. Consistent with the results of these ensemble studies, single-molecule DNA stretching studies show that while WT FIV NC has reduced stacking capability relative to HIV-1 NC, the aromatic switch mutant recovers the ability to intercalate between the DNA bases. Our results demonstrate that altering the position of a single aromatic residue switches the binding mode of FIV NC from primarily electrostatic binding to more non-electrostatic binding, conferring upon it NA interaction properties comparable to that of HIV-1 NC.
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Affiliation(s)
- Hao Wu
- Northeastern University, Department of Physics, Boston, MA 02115, USA
| | - Wei Wang
- The Ohio State University, Department of Chemistry and Biochemistry, Center for Retrovirus Research, and Center for RNA Biology, Columbus, OH 43210, USA
| | - Nada Naiyer
- The Ohio State University, Department of Chemistry and Biochemistry, Center for Retrovirus Research, and Center for RNA Biology, Columbus, OH 43210, USA
| | - Eric Fichtenbaum
- The Ohio State University, Department of Chemistry and Biochemistry, Center for Retrovirus Research, and Center for RNA Biology, Columbus, OH 43210, USA
| | - Dominic F Qualley
- The Ohio State University, Department of Chemistry and Biochemistry, Center for Retrovirus Research, and Center for RNA Biology, Columbus, OH 43210, USA
| | - Micah J McCauley
- Northeastern University, Department of Physics, Boston, MA 02115, USA
| | - Robert J Gorelick
- AIDS and Cancer Virus Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA
| | - Ioulia Rouzina
- University of Minnesota, Department of Biochemistry, Molecular Biology, and Biophysics, Minneapolis, MN 55455, USA
| | - Karin Musier-Forsyth
- The Ohio State University, Department of Chemistry and Biochemistry, Center for Retrovirus Research, and Center for RNA Biology, Columbus, OH 43210, USA.
| | - Mark C Williams
- Northeastern University, Department of Physics, Boston, MA 02115, USA.
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25
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Griffis JW, Safranovitch MM, Vyas SP, Gerrin S, Protozanova E, Malkin G, Meltzer RH. Single molecule DNA intercalation in continuous homogenous elongational flow. LAB ON A CHIP 2014; 14:3881-3893. [PMID: 25133764 DOI: 10.1039/c4lc00781f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Sequence-nonspecific staining of DNA with intercalating fluorophores is required for fluorescence-based length estimation of elongated DNA in optical mapping techniques. However, the observed length of a DNA molecule is affected by the relative concentrations of DNA and dye. In some applications, predetermination of DNA concentration may not be possible. Here we present a microfluidic approach in which individual DNA molecules are entrained by converging laminar sheath flows containing the intercalating dye PO-PRO-1. This provides uniform staining regardless of DNA concentration, and uniform elastic stretching of DNA in continuous elongational flow. On-chip intercalation provides a unique process for concentration-independent staining of long DNA fragments for the optical mapping method Genome Sequence Scanning (GSS), and normalizes intramolecular elasticity across a broad range of molecule lengths. These advances permit accurate mapping of observed molecules to sequence derived templates, thus improving detection of complex bacterial mixtures using GSS.
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26
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Zargarian L, Tisné C, Barraud P, Xu X, Morellet N, René B, Mély Y, Fossé P, Mauffret O. Dynamics of linker residues modulate the nucleic acid binding properties of the HIV-1 nucleocapsid protein zinc fingers. PLoS One 2014; 9:e102150. [PMID: 25029439 PMCID: PMC4100767 DOI: 10.1371/journal.pone.0102150] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Accepted: 06/16/2014] [Indexed: 01/20/2023] Open
Abstract
The HIV-1 nucleocapsid protein (NC) is a small basic protein containing two zinc fingers (ZF) separated by a short linker. It is involved in several steps of the replication cycle and acts as a nucleic acid chaperone protein in facilitating nucleic acid strand transfers occurring during reverse transcription. Recent analysis of three-dimensional structures of NC-nucleic acids complexes established a new property: the unpaired guanines targeted by NC are more often inserted in the C-terminal zinc finger (ZF2) than in the N-terminal zinc finger (ZF1). Although previous NMR dynamic studies were performed with NC, the dynamic behavior of the linker residues connecting the two ZF domains remains unclear. This prompted us to investigate the dynamic behavior of the linker residues. Here, we collected 15N NMR relaxation data and used for the first time data at several fields to probe the protein dynamics. The analysis at two fields allows us to detect a slow motion occurring between the two domains around a hinge located in the linker at the G35 position. However, the amplitude of motion appears limited in our conditions. In addition, we showed that the neighboring linker residues R29, A30, P31, R32, K33 displayed restricted motion and numerous contacts with residues of ZF1. Our results are fully consistent with a model in which the ZF1-linker contacts prevent the ZF1 domain to interact with unpaired guanines, whereas the ZF2 domain is more accessible and competent to interact with unpaired guanines. In contrast, ZF1 with its large hydrophobic plateau is able to destabilize the double-stranded regions adjacent to the guanines bound by ZF2. The linker residues and the internal dynamics of NC regulate therefore the different functions of the two zinc fingers that are required for an optimal chaperone activity.
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Affiliation(s)
- Loussiné Zargarian
- Laboratoire de Biologie et Pharmacologie Appliquée, Ecole Normale Supérieure de Cachan, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 8113, Cachan, France
| | - Carine Tisné
- Laboratoire de Cristallographie et RMN Biologiques, Université Paris Descartes, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 8015, Paris, France
| | - Pierre Barraud
- Laboratoire de Cristallographie et RMN Biologiques, Université Paris Descartes, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 8015, Paris, France
| | - Xiaoqian Xu
- Laboratoire de Biologie et Pharmacologie Appliquée, Ecole Normale Supérieure de Cachan, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 8113, Cachan, France
- Department of Life Sciences, East China Normal University, Shanghai, People's Republic of China
| | - Nelly Morellet
- Centre de Recherches de Gif, Institut de Chimie des Substances Naturelles, Centre National de la Recherche Scientifique, Gif sur Yvette, France
| | - Brigitte René
- Laboratoire de Biologie et Pharmacologie Appliquée, Ecole Normale Supérieure de Cachan, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 8113, Cachan, France
| | - Yves Mély
- Laboratoire de Biophotonique et Pharmacologie, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7213, Faculté de Pharmacie, Université de Strasbourg, Illkirch, France
| | - Philippe Fossé
- Laboratoire de Biologie et Pharmacologie Appliquée, Ecole Normale Supérieure de Cachan, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 8113, Cachan, France
| | - Olivier Mauffret
- Laboratoire de Biologie et Pharmacologie Appliquée, Ecole Normale Supérieure de Cachan, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 8113, Cachan, France
- * E-mail:
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27
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Retrospective on the all-in-one retroviral nucleocapsid protein. Virus Res 2014; 193:2-15. [PMID: 24907482 PMCID: PMC7114435 DOI: 10.1016/j.virusres.2014.05.011] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Revised: 05/11/2014] [Accepted: 05/11/2014] [Indexed: 01/08/2023]
Abstract
This retrospective reviews 30 years of research on the retroviral nucleocapsid protein (NC) focusing on HIV-1 NC. Originally considered as a non-specific nucleic-acid binding protein, NC has seminal functions in virus replication. Indeed NC turns out to be a all-in-one viral protein that chaperones viral DNA synthesis and integration, and virus formation. As a chaperone NC provides assistance to genetic recombination thus allowing the virus to escape the immune response and antiretroviral therapies against HIV-1.
This review aims at briefly presenting a retrospect on the retroviral nucleocapsid protein (NC), from an unspecific nucleic acid binding protein (NABP) to an all-in-one viral protein with multiple key functions in the early and late phases of the retrovirus replication cycle, notably reverse transcription of the genomic RNA and viral DNA integration into the host genome, and selection of the genomic RNA together with the initial steps of virus morphogenesis. In this context we will discuss the notion that NC protein has a flexible conformation and is thus a member of the growing family of intrinsically disordered proteins (IDPs) where disorder may account, at least in part, for its function as a nucleic acid (NA) chaperone and possibly as a protein chaperone vis-à-vis the viral DNA polymerase during reverse transcription. Lastly, we will briefly review the development of new anti-retroviral/AIDS compounds targeting HIV-1 NC because it represents an ideal target due to its multiple roles in the early and late phases of virus replication and its high degree of conservation.
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28
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Heller I, Hoekstra TP, King GA, Peterman EJG, Wuite GJL. Optical tweezers analysis of DNA-protein complexes. Chem Rev 2014; 114:3087-119. [PMID: 24443844 DOI: 10.1021/cr4003006] [Citation(s) in RCA: 113] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Iddo Heller
- Department of Physics and Astronomy and LaserLaB Amsterdam, VU University Amsterdam , De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
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29
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Wu H, Mitra M, Naufer MN, McCauley MJ, Gorelick RJ, Rouzina I, Musier-Forsyth K, Williams MC. Differential contribution of basic residues to HIV-1 nucleocapsid protein's nucleic acid chaperone function and retroviral replication. Nucleic Acids Res 2013; 42:2525-37. [PMID: 24293648 PMCID: PMC3936775 DOI: 10.1093/nar/gkt1227] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
The human immunodeficiency virus type 1 (HIV-1) nucleocapsid (NC) protein contains 15 basic residues located throughout its 55-amino acid sequence, as well as one aromatic residue in each of its two CCHC-type zinc finger motifs. NC facilitates nucleic acid (NA) rearrangements via its chaperone activity, but the structural basis for this activity and its consequences in vivo are not completely understood. Here, we investigate the role played by basic residues in the N-terminal domain, the N-terminal zinc finger and the linker region between the two zinc fingers. We use in vitro ensemble and single-molecule DNA stretching experiments to measure the characteristics of wild-type and mutant HIV-1 NC proteins, and correlate these results with cell-based HIV-1 replication assays. All of the cationic residue mutations lead to NA interaction defects, as well as reduced HIV-1 infectivity, and these effects are most pronounced on neutralizing all five N-terminal cationic residues. HIV-1 infectivity in cells is correlated most strongly with NC’s NA annealing capabilities as well as its ability to intercalate the DNA duplex. Although NC’s aromatic residues participate directly in DNA intercalation, our findings suggest that specific basic residues enhance these interactions, resulting in optimal NA chaperone activity.
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Affiliation(s)
- Hao Wu
- Department of Physics, Northeastern University, Boston, MA 02115, USA, Department of Chemistry and Biochemistry, Center for RNA Biology, and Center for Retrovirus Research, The Ohio State University, Columbus, OH 43210, USA, AIDS and Cancer Virus Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA and Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
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30
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Zhang HY, Liu YR, Ji C, Li W, Dou SX, Xie P, Wang WC, Zhang LY, Wang PY. Oxaliplatin and its enantiomer induce different condensation dynamics of single DNA molecules. PLoS One 2013; 8:e71556. [PMID: 23951187 PMCID: PMC3741182 DOI: 10.1371/journal.pone.0071556] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2013] [Accepted: 07/02/2013] [Indexed: 11/19/2022] Open
Abstract
The interactions of DNA with oxaliplatin (Pt(R,R-DACH)) or its enantiomer (Pt(S,S-DACH)) were investigated using magnetic tweezers and atomic force microscope. In the process of DNA condensation induced by Pt-DACH, only diadducts and micro-loops are formed at low Pt-DACH concentrations, while at high Pt-DACH concentrations, besides the diadducts and micro-loops, long-range cross-links are also formed. The diadduct formation rate of Pt(R,R-DACH) is higher than that of Pt(S,S-DACH). However, the proportions of micro-loops and long-range cross-links for Pt(S,S-DACH) are higher than those for Pt(R,R-DACH). We propose a model to explain these differences between the effect of Pt(R,R-DACH) and that of Pt(S,S-DACH) on DNA condensation. The study has strong implications for the understanding of the effect of chirality on the interaction between Pt-DACH and DNA and the kinetics of DNA condensation induced by platinum complexes.
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Affiliation(s)
- Hong-Yan Zhang
- Key Laboratory of Soft Matter Physics, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
| | - Yu-Ru Liu
- Key Laboratory of Soft Matter Physics, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
| | - Chao Ji
- Key Laboratory of Soft Matter Physics, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
| | - Wei Li
- Key Laboratory of Soft Matter Physics, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
| | - Shuo-Xing Dou
- Key Laboratory of Soft Matter Physics, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
| | - Ping Xie
- Key Laboratory of Soft Matter Physics, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
| | - Wei-Chi Wang
- Key Laboratory of Soft Matter Physics, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
| | - Ling-Yun Zhang
- Key Laboratory of Soft Matter Physics, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
| | - Peng-Ye Wang
- Key Laboratory of Soft Matter Physics, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
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31
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Sleiman D, Barraud P, Brachet F, Tisne C. The Interaction between tRNA(Lys) 3 and the primer activation signal deciphered by NMR spectroscopy. PLoS One 2013; 8:e64700. [PMID: 23762248 PMCID: PMC3675109 DOI: 10.1371/journal.pone.0064700] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Accepted: 04/17/2013] [Indexed: 11/23/2022] Open
Abstract
The initiation of reverse transcription of the human immunodeficiency virus type 1 (HIV-1) requires the opening of the three-dimensional structure of the primer tRNALys3 for its annealing to the viral RNA at the primer binding site (PBS). Despite the fact that the result of this rearrangement is thermodynamically more stable, there is a high-energy barrier that requires the chaperoning activity of the viral nucleocapsid protein. In addition to the nucleotide complementarity to the PBS, several regions of tRNALys3 have been described as interacting with the viral genomic RNA. Among these sequences, a sequence of the viral genome called PAS for “primer activation signal” was proposed to interact with the T-arm of tRNALys3, this interaction stimulating the initiation of reverse transcription. In this report, we investigate the formation of this additional interaction with NMR spectroscopy, using a simple system composed of the primer tRNALys3, the 18 nucleotides of the PBS, the PAS (8 nucleotides) encompassed or not in a hairpin structure, and the nucleocapsid protein. Our NMR study provides molecular evidence of the existence of this interaction and highlights the role of the nucleocapsid protein in promoting this additional RNA-RNA annealing. This study presents the first direct observation at a single base-pair resolution of the PAS/anti-PAS association, which has been proposed to be involved in the chronological regulation of the reverse transcription.
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Affiliation(s)
- Dona Sleiman
- Laboratoire de Cristallographie et RMN biologiques, CNRS, Université Paris Descartes, Paris Sorbonne Cité, Paris, France
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32
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Ouyang W, Okaine S, McPike MP, Lin Y, Borer PN. Probing the RNA Binding Surface of the HIV-1 Nucleocapsid Protein by Site-Directed Mutagenesis. Biochemistry 2013; 52:3358-68. [DOI: 10.1021/bi400125z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- Wei Ouyang
- Graduate
Program in Structural Biology, Biochemistry, and Biophysics and ‡Department of
Chemistry, Syracuse University, Syracuse, New York 13244-4100, United States
| | - Stephen Okaine
- Graduate
Program in Structural Biology, Biochemistry, and Biophysics and ‡Department of
Chemistry, Syracuse University, Syracuse, New York 13244-4100, United States
| | - Mark P. McPike
- Graduate
Program in Structural Biology, Biochemistry, and Biophysics and ‡Department of
Chemistry, Syracuse University, Syracuse, New York 13244-4100, United States
| | - Yong Lin
- Graduate
Program in Structural Biology, Biochemistry, and Biophysics and ‡Department of
Chemistry, Syracuse University, Syracuse, New York 13244-4100, United States
| | - Philip N. Borer
- Graduate
Program in Structural Biology, Biochemistry, and Biophysics and ‡Department of
Chemistry, Syracuse University, Syracuse, New York 13244-4100, United States
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33
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Godet J, Kenfack C, Przybilla F, Richert L, Duportail G, Mély Y. Site-selective probing of cTAR destabilization highlights the necessary plasticity of the HIV-1 nucleocapsid protein to chaperone the first strand transfer. Nucleic Acids Res 2013; 41:5036-48. [PMID: 23511968 PMCID: PMC3643577 DOI: 10.1093/nar/gkt164] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The HIV-1 nucleocapsid protein (NCp7) is a nucleic acid chaperone required during reverse transcription. During the first strand transfer, NCp7 is thought to destabilize cTAR, the (−)DNA copy of the TAR RNA hairpin, and subsequently direct the TAR/cTAR annealing through the zipping of their destabilized stem ends. To further characterize the destabilizing activity of NCp7, we locally probe the structure and dynamics of cTAR by steady-state and time resolved fluorescence spectroscopy. NC(11–55), a truncated NCp7 version corresponding to its zinc-finger domain, was found to bind all over the sequence and to preferentially destabilize the penultimate double-stranded segment in the lower part of the cTAR stem. This destabilization is achieved through zinc-finger–dependent binding of NC to the G10 and G50 residues. Sequence comparison further revealed that C•A mismatches close to the two G residues were critical for fine tuning the stability of the lower part of the cTAR stem and conferring to G10 and G50 the appropriate mobility and accessibility for specific recognition by NC. Our data also highlight the necessary plasticity of NCp7 to adapt to the sequence and structure variability of cTAR to chaperone its annealing with TAR through a specific pathway.
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Affiliation(s)
- Julien Godet
- Laboratoire de Biophotonique et Pharmacologie, Faculté de Pharmacie, UMR 7213 CNRS, Université de Strasbourg, 67401 Illkirch, France
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Wu H, Mitra M, McCauley MJ, Thomas JA, Rouzina I, Musier-Forsyth K, Williams MC, Gorelick RJ. Aromatic residue mutations reveal direct correlation between HIV-1 nucleocapsid protein's nucleic acid chaperone activity and retroviral replication. Virus Res 2013; 171:263-77. [PMID: 22814429 PMCID: PMC3745225 DOI: 10.1016/j.virusres.2012.07.008] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Revised: 07/02/2012] [Accepted: 07/07/2012] [Indexed: 10/28/2022]
Abstract
The human immunodeficiency virus type 1 (HIV-1) nucleocapsid (NC) protein plays an essential role in several stages of HIV-1 replication. One important function of HIV-1 NC is to act as a nucleic acid chaperone, in which the protein facilitates nucleic acid rearrangements important for reverse transcription and recombination. NC contains only 55 amino acids, with 15 basic residues and two zinc fingers, each having a single aromatic residue (Phe16 and Trp37). Despite its simple structure, HIV-1 NC appears to have optimal chaperone activity, including the ability to strongly aggregate nucleic acids, destabilize nucleic acid secondary structure, and facilitate rapid nucleic acid annealing. Here we combine single molecule DNA stretching experiments with ensemble solution studies of protein-nucleic acid binding affinity, oligonucleotide annealing, and nucleic acid aggregation to measure the characteristics of wild-type (WT) and aromatic residue mutants of HIV-1 NC that are important for nucleic acid chaperone activity. These in vitro results are compared to in vivo HIV-1 replication for viruses containing the same mutations. This work allows us to directly relate HIV-1 NC structure with its function as a nucleic acid chaperone in vitro and in vivo. We show that replacement of either aromatic residue with another aromatic residue results in a protein that strongly resembles WT NC. In contrast, single amino acid substitutions of either Phe16Ala or Trp37Ala significantly slow down NC's DNA interaction kinetics, while retaining some helix-destabilization capability. A double Phe16Ala/Trp37Ala substitution further reduces the latter activity. Surprisingly, the ensemble nucleic acid binding, annealing, and aggregation properties are not significantly altered for any mutant except the double aromatic substitution with Ala. Thus, elimination of a single aromatic residue from either zinc finger strongly reduces NC's chaperone activity as determined by single molecule DNA stretching experiments without significantly altering its ensemble-averaged biochemical properties. Importantly, the substitution of aromatic residues with Ala progressively decreases NC's nucleic acid chaperone activity while also progressively inhibiting viral replication. Taken together, these data support the critical role of HIV-1 NC's aromatic residues, and establish a direct and statistically significant correlation between nucleic acid chaperone activity and viral replication.
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Affiliation(s)
- Hao Wu
- Northeastern University, Department of Physics, Boston, MA 02115, USA
| | - Mithun Mitra
- The Ohio State University, Department of Chemistry and Biochemistry, Center for Retrovirus Research, Center for RNA Biology, Columbus, OH 43210, USA
| | - Micah J. McCauley
- Northeastern University, Department of Physics, Boston, MA 02115, USA
| | - James A. Thomas
- AIDS and Cancer Virus Program, SAIC-Frederick, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA
| | - Ioulia Rouzina
- University of Minnesota, Department of Biochemistry, Molecular Biology, and Biophysics, Minneapolis, MN 55455, USA
| | - Karin Musier-Forsyth
- The Ohio State University, Department of Chemistry and Biochemistry, Center for Retrovirus Research, Center for RNA Biology, Columbus, OH 43210, USA
| | - Mark C. Williams
- Northeastern University, Department of Physics, Boston, MA 02115, USA
| | - Robert J. Gorelick
- AIDS and Cancer Virus Program, SAIC-Frederick, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA
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35
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Hergott CB, Mitra M, Guo J, Wu T, Miller JT, Iwatani Y, Gorelick RJ, Levin JG. Zinc finger function of HIV-1 nucleocapsid protein is required for removal of 5'-terminal genomic RNA fragments: a paradigm for RNA removal reactions in HIV-1 reverse transcription. Virus Res 2013; 171:346-55. [PMID: 23149014 PMCID: PMC3578084 DOI: 10.1016/j.virusres.2012.08.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2012] [Revised: 07/27/2012] [Accepted: 08/20/2012] [Indexed: 11/28/2022]
Abstract
During (-) strong-stop DNA [(-) SSDNA] synthesis, RNase H cleavage of genomic viral RNA generates small 5'-terminal RNA fragments (14-18 nt) that remain annealed to the DNA. Unless these fragments are removed, the minus-strand transfer reaction, required for (-) SSDNA elongation, cannot occur. Here, we describe the mechanism of 5'-terminal RNA removal and the roles of HIV-1 nucleocapsid protein (NC) and RNase H cleavage in this process. Using an NC-dependent system that models minus-strand transfer, we show that the presence of short terminal fragments pre-annealed to (-) SSDNA has no impact on strand transfer, implying efficient fragment removal. Moreover, in reactions with an RNase H(-) reverse transcriptase mutant, NC alone is able to facilitate fragment removal, albeit less efficiently than in the presence of both RNase H activity and NC. Results obtained from novel electrophoretic gel mobility shift and Förster Resonance Energy Transfer assays, which each directly measure RNA fragment release from a duplex in the absence of DNA synthesis, demonstrate for the first time that the architectural integrity of NC's zinc finger (ZF) domains is absolutely required for this reaction. This suggests that NC's helix destabilizing activity (associated with the ZFs) facilitates strand exchange through the displacement of these short terminal RNAs by the longer 3' acceptor RNA, which forms a more stable duplex with (-) SSDNA. Taken together with previously published results, we conclude that NC-mediated fragment removal is linked mechanistically with selection of the correct primer for plus-strand DNA synthesis and tRNA removal step prior to plus-strand transfer. Thus, HIV-1 has evolved a single mechanism for these RNA removal reactions that are critical for successful reverse transcription.
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MESH Headings
- DNA, Viral/chemistry
- DNA, Viral/genetics
- DNA, Viral/metabolism
- Gene Expression Regulation, Viral
- HIV-1/chemistry
- HIV-1/genetics
- HIV-1/metabolism
- RNA Processing, Post-Transcriptional
- RNA, Viral/chemistry
- RNA, Viral/genetics
- RNA, Viral/metabolism
- Reverse Transcription
- Zinc Fingers
- gag Gene Products, Human Immunodeficiency Virus/chemistry
- gag Gene Products, Human Immunodeficiency Virus/genetics
- gag Gene Products, Human Immunodeficiency Virus/metabolism
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Affiliation(s)
- Christopher B. Hergott
- Section on Viral Gene Regulation, Program on Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892-2780, USA
| | - Mithun Mitra
- Section on Viral Gene Regulation, Program on Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892-2780, USA
| | - Jianhui Guo
- Section on Viral Gene Regulation, Program on Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892-2780, USA
| | - Tiyun Wu
- Section on Viral Gene Regulation, Program on Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892-2780, USA
| | - Jennifer T. Miller
- Reverse Transcriptase Biochemistry Section, HIV Drug Resistance Program, National Cancer Institute, National Institutes of Health, Frederick National Laboratory for Cancer Research, Frederick, MD 21702-1201, USA
| | - Yasumasa Iwatani
- Section on Viral Gene Regulation, Program on Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892-2780, USA
| | - Robert J. Gorelick
- AIDS and Cancer Virus Program, SAIC-Frederick, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702-1201, USA
| | - Judith G. Levin
- Section on Viral Gene Regulation, Program on Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892-2780, USA
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Perry CC, Urata SM, Lee M, Aguilera JA, Milligan JR. Radioprotective effects produced by the condensation of plasmid DNA with avidin and biotinylated gold nanoparticles. RADIATION AND ENVIRONMENTAL BIOPHYSICS 2012; 51:457-468. [PMID: 22825766 DOI: 10.1007/s00411-012-0429-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2012] [Accepted: 06/28/2012] [Indexed: 06/01/2023]
Abstract
The treatment of aqueous solutions of plasmid DNA with the protein avidin results in significant changes in physical, chemical, and biochemical properties. These effects include increased light scattering, formation of micron-sized particles containing both DNA and protein, and plasmid protection against thermal denaturation, radical attack, and nuclease digestion. All of these changes are consistent with condensation of the plasmid by avidin. Avidin can be displaced from the plasmid at higher ionic strengths. Avidin is not displaced from the plasmid by an excess of a tetra-arginine ligand, nor by the presence of biotin. Therefore, this system offers the opportunity to reversibly bind biotin-labeled species to a condensed DNA-protein complex. An example application is the use of biotinylated gold nanoparticles. This system offers the ability to examine in better detail the chemical mechanisms involved in important radiobiological effects. Examples include protein modulation of radiation damage to DNA, and radiosensitization by gold nanoparticles.
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Affiliation(s)
- Christopher C Perry
- Department of Biochemistry, Loma Linda University, 11085 Campus Street, Loma Linda, CA, 92350, USA
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37
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Doetsch M, Stampfl S, Fürtig B, Beich-Frandsen M, Saxena K, Lybecker M, Schroeder R. Study of E. coli Hfq's RNA annealing acceleration and duplex destabilization activities using substrates with different GC-contents. Nucleic Acids Res 2012; 41:487-97. [PMID: 23104381 PMCID: PMC3592463 DOI: 10.1093/nar/gks942] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Folding of RNA molecules into their functional three-dimensional structures is often supported by RNA chaperones, some of which can catalyse the two elementary reactions helix disruption and helix formation. Hfq is one such RNA chaperone, but its strand displacement activity is controversial. Whereas some groups found Hfq to destabilize secondary structures, others did not observe such an activity with their RNA substrates. We studied Hfq’s activities using a set of short RNAs of different thermodynamic stabilities (GC-contents from 4.8% to 61.9%), but constant length. We show that Hfq’s strand displacement as well as its annealing activity are strongly dependent on the substrate’s GC-content. However, this is due to Hfq’s preferred binding of AU-rich sequences and not to the substrate’s thermodynamic stability. Importantly, Hfq catalyses both annealing and strand displacement with comparable rates for different substrates, hinting at RNA strand diffusion and annealing nucleation being rate-limiting for both reactions. Hfq’s strand displacement activity is a result of the thermodynamic destabilization of the RNA through preferred single-strand binding whereas annealing acceleration is independent from Hfq’s thermodynamic influence. Therefore, the two apparently disparate activities annealing acceleration and duplex destabilization are not in energetic conflict with each other.
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Affiliation(s)
- Martina Doetsch
- Department for Biochemistry, Max F Perutz Laboratories, Dr-Bohrgasse 9, 1030 Vienna, Austria
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38
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Godet J, Boudier C, Humbert N, Ivanyi-Nagy R, Darlix JL, Mély Y. Comparative nucleic acid chaperone properties of the nucleocapsid protein NCp7 and Tat protein of HIV-1. Virus Res 2012; 169:349-60. [PMID: 22743066 PMCID: PMC7114403 DOI: 10.1016/j.virusres.2012.06.021] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Revised: 06/18/2012] [Accepted: 06/19/2012] [Indexed: 10/28/2022]
Abstract
RNA chaperones are proteins able to rearrange nucleic acid structures towards their most stable conformations. In retroviruses, the reverse transcription of the viral RNA requires multiple and complex nucleic acid rearrangements that need to be chaperoned. HIV-1 has evolved different viral-encoded proteins with chaperone activity, notably Tat and the well described nucleocapsid protein NCp7. We propose here an overview of the recent reports that examine and compare the nucleic acid chaperone properties of Tat and NCp7 during reverse transcription to illustrate the variety of mechanisms of action of the nucleic acid chaperone proteins.
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Affiliation(s)
- Julien Godet
- Laboratoire de Biophotonique et Pharmacologie, Faculté de Pharmacie, UMR 7213 CNRS, Université de Strasbourg, 67401 Illkirch, France
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39
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Smyth RP, Davenport MP, Mak J. The origin of genetic diversity in HIV-1. Virus Res 2012; 169:415-29. [PMID: 22728444 DOI: 10.1016/j.virusres.2012.06.015] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2012] [Revised: 06/10/2012] [Accepted: 06/12/2012] [Indexed: 10/28/2022]
Abstract
One of the hallmarks of HIV infection is the rapid development of a genetically complex population (quasispecies) from an initially limited number of infectious particles. Genetic diversity remains one of the major obstacles to eradication of HIV. The viral quasispecies can respond rapidly to selective pressures, such as that imposed by the immune system and antiretroviral therapy, and frustrates vaccine design efforts. Two unique features of retroviral replication are responsible for the unprecedented variation generated during infection. First, mutations are frequently introduced into the viral genome by the error prone viral reverse transcriptase and through the actions of host cellular factors, such as the APOBEC family of nucleic acid editing enzymes. Second, the HIV reverse transcriptase can utilize both copies of the co-packaged viral genome in a process termed retroviral recombination. When the co-packaged viral genomes are genetically different, retroviral recombination can lead to the shuffling of mutations between viral genomes in the quasispecies. This review outlines the stages of the retroviral life cycle where genetic variation is introduced, focusing on the principal mechanisms of mutation and recombination. Understanding the mechanistic origin of genetic diversity is essential to combating HIV.
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Affiliation(s)
- Redmond P Smyth
- Centre for Virology, Burnet Institute, 85 Commercial Road, Melbourne, Victoria 3004, Australia
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40
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Wang H, Musier-Forsyth K, Falk C, Barbara PF. Single-molecule spectroscopic study of dynamic nanoscale DNA bending behavior of HIV-1 nucleocapsid protein. J Phys Chem B 2012; 117:4183-96. [PMID: 22591315 DOI: 10.1021/jp3018259] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
We have studied the conformational dynamics associated with the nanoscale DNA bending induced by human immunodeficiency virus type 1 (HIV-1) nucleocapsid (NC) protein using single-molecule Förster resonance energy transfer (SM-FRET). To gain molecular-level insights into how the HIV-1 NC locally distorts the structures of duplexed DNA segments, the dynamics, reversibility, and sequence specificity of the DNA bending behavior of NC have been systematically studied. We have performed SM-FRET measurements on a series of duplexed DNA segments with varying sequences, lengths, and local structures in the presence of the wide-type HIV-1 NC and NC mutants lacking either the basic N-terminal domain or the zinc fingers. On the basis of the SM-FRET results, we have proposed a possible mechanism for the NC-induced DNA bending in which both NC's zinc fingers and N-terminal domain are found to play crucial roles. The SM-FRET results reported here add new mechanistic insights into the biological behaviors and functions of HIV-1 NC as a retroviral DNA-architectural protein which may play critical roles in the compaction, nuclear import, and integration of the proviral DNA during the retroviral life cycle.
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Affiliation(s)
- Hui Wang
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, USA.
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41
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Chaurasiya KR, Geertsema H, Cristofari G, Darlix JL, Williams MC. A single zinc finger optimizes the DNA interactions of the nucleocapsid protein of the yeast retrotransposon Ty3. Nucleic Acids Res 2012; 40:751-60. [PMID: 21917850 PMCID: PMC3258130 DOI: 10.1093/nar/gkr726] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Revised: 08/09/2011] [Accepted: 08/23/2011] [Indexed: 12/18/2022] Open
Abstract
Reverse transcription in retroviruses and retrotransposons requires nucleic acid chaperones, which drive the rearrangement of nucleic acid conformation. The nucleic acid chaperone properties of the human immunodeficiency virus type-1 (HIV-1) nucleocapsid (NC) protein have been extensively studied, and nucleic acid aggregation, duplex destabilization and rapid binding kinetics have been identified as major components of its activity. However, the properties of other nucleic acid chaperone proteins, such as retrotransposon Ty3 NC, a likely ancestor of HIV-1 NC, are not well understood. In addition, it is unclear whether a single zinc finger is sufficient to optimize the properties characteristic of HIV-1 NC. We used single-molecule DNA stretching as a method for detailed characterization of Ty3 NC chaperone activity. We found that wild type Ty3 NC aggregates single- and double-stranded DNA, weakly stabilizes dsDNA, and exhibits rapid binding kinetics. Single-molecule studies in the presence of Ty3 NC mutants show that the N-terminal basic residues and the unique zinc finger at the C-terminus are required for optimum chaperone activity in this system. While the single zinc finger is capable of optimizing Ty3 NC's DNA interaction kinetics, two zinc fingers may be necessary in order to facilitate the DNA destabilization exhibited by HIV-1 NC.
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Affiliation(s)
- Kathy R. Chaurasiya
- Department of Physics, Northeastern University, Boston, MA, USA, Unité de Virologie Humaine INSERM 758, IFR 128 Ecole Normale Supérieure de Lyon, 46 allée d'Italie, 69364 Lyon, France and Center for Interdisciplinary Research on Complex Systems, Northeastern University, Boston, MA, USA
| | - Hylkje Geertsema
- Department of Physics, Northeastern University, Boston, MA, USA, Unité de Virologie Humaine INSERM 758, IFR 128 Ecole Normale Supérieure de Lyon, 46 allée d'Italie, 69364 Lyon, France and Center for Interdisciplinary Research on Complex Systems, Northeastern University, Boston, MA, USA
| | - Gaël Cristofari
- Department of Physics, Northeastern University, Boston, MA, USA, Unité de Virologie Humaine INSERM 758, IFR 128 Ecole Normale Supérieure de Lyon, 46 allée d'Italie, 69364 Lyon, France and Center for Interdisciplinary Research on Complex Systems, Northeastern University, Boston, MA, USA
| | - Jean-Luc Darlix
- Department of Physics, Northeastern University, Boston, MA, USA, Unité de Virologie Humaine INSERM 758, IFR 128 Ecole Normale Supérieure de Lyon, 46 allée d'Italie, 69364 Lyon, France and Center for Interdisciplinary Research on Complex Systems, Northeastern University, Boston, MA, USA
| | - Mark C. Williams
- Department of Physics, Northeastern University, Boston, MA, USA, Unité de Virologie Humaine INSERM 758, IFR 128 Ecole Normale Supérieure de Lyon, 46 allée d'Italie, 69364 Lyon, France and Center for Interdisciplinary Research on Complex Systems, Northeastern University, Boston, MA, USA
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42
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Characterization of the inhibition mechanism of HIV-1 nucleocapsid protein chaperone activities by methylated oligoribonucleotides. Antimicrob Agents Chemother 2011; 56:1010-8. [PMID: 22083480 DOI: 10.1128/aac.05614-11] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Since currently available therapies against HIV/AIDS still show important drawbacks, the development of novel anti-HIV treatments is a key issue. We recently characterized methylated oligoribonucleotides (mONs) that extensively inhibit HIV-1 replication in primary T cells at nanomolar concentrations. The mONs were shown to target both HIV-1 reverse transcriptase (RT) and the nucleocapsid protein (NC), which is an essential partner of RT during viral DNA synthesis. To further understand the mechanism of such mONs, we studied by isothermal titration calorimetry and fluorescence-based techniques their NC binding properties and ability to inhibit the nucleic acid chaperone properties of NC. Notably, we investigated the ability of mONs to inhibit the NC-induced destabilization of the HIV-1 cTAR (complementary DNA sequence to TAR [transactivation response element]) stem-loop and the NC-promoted cTAR annealing to its complementary sequence, required at the early stage of HIV-1 viral DNA synthesis. Moreover, we compared the activity of the mONs to that of a number of modified and nonmodified oligonucleotides. Results show that the mONs inhibit NC by a competitive mechanism whereby the mONs tightly bind the NC peptide, mainly through nonelectrostatic interactions with the hydrophobic platform at the top of the NC zinc fingers. Taken together, these results favor the notion that the mONs impair the process of the RT-directed viral DNA synthesis by sequestering NC molecules, thus preventing the chaperoning of viral DNA synthesis by NC. These findings contribute to the understanding of the molecular basis for NC inhibition by mONs, which could be used for the rational design of antiretroviral compounds targeting HIV-1 NC protein.
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43
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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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44
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Purzycka KJ, Pachulska-Wieczorek K, Adamiak RW. The in vitro loose dimer structure and rearrangements of the HIV-2 leader RNA. Nucleic Acids Res 2011; 39:7234-48. [PMID: 21622659 PMCID: PMC3167612 DOI: 10.1093/nar/gkr385] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
RNA dimerization is an essential step in the retroviral life cycle. Dimerization and encapsidation signals, closely linked in HIV-2, are located in the leader RNA region. The SL1 motif and nucleocapsid protein are considered important for both processes. In this study, we show the structure of the HIV-2 leader RNA (+1–560) captured as a loose dimer. Potential structural rearrangements within the leader RNA were studied. In the loose dimer form, the HIV-2 leader RNA strand exists in vitro as a single global fold. Two kissing loop interfaces within the loose dimer were identified: SL1/SL1 and TAR/TAR. Evidence for these findings is provided by RNA probing using SHAPE, chemical reagents, enzymes, non-denaturing PAGE mobility assays, antisense oligonucleotides hybridization and analysis of an RNA mutant. Both TAR and SL1 as isolated domains are bound by recombinant NCp8 protein with high affinity, contrary to the hairpins downstream of SL1. Foot-printing of the SL1/NCp8 complex indicates that the major binding site maps to the SL1 upper stem. Taken together, these data suggest a model in which TAR hairpin III, the segment of SL1 proximal to the loop and the PAL palindromic sequence play specific roles in the initiation of dimerization.
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Affiliation(s)
- Katarzyna J Purzycka
- Laboratory of Structural Chemistry of Nucleic Acids, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznań, Poland
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45
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Godet J, Ramalanjaona N, Sharma KK, Richert L, de Rocquigny H, Darlix JL, Duportail G, Mély Y. Specific implications of the HIV-1 nucleocapsid zinc fingers in the annealing of the primer binding site complementary sequences during the obligatory plus strand transfer. Nucleic Acids Res 2011; 39:6633-45. [PMID: 21543454 PMCID: PMC3159456 DOI: 10.1093/nar/gkr274] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Synthesis of the HIV-1 viral DNA by reverse transcriptase involves two obligatory strand transfer reactions. The second strand transfer corresponds to the annealing of the (−) and (+) DNA copies of the primer binding site (PBS) sequence which is chaperoned by the nucleocapsid protein (NCp7). NCp7 modifies the (+)/(−)PBS annealing mechanism by activating a loop–loop kissing pathway that is negligible without NCp7. To characterize in depth the dynamics of the loop in the NCp7/PBS nucleoprotein complexes, we investigated the time-resolved fluorescence parameters of a (−)PBS derivative containing the fluorescent nucleoside analogue 2-aminopurine at positions 6, 8 or 10. The NCp7-directed switch of (+)/(−)PBS annealing towards the loop pathway was associated to a drastic restriction of the local DNA dynamics, indicating that NCp7 can ‘freeze’ PBS conformations competent for annealing via the loops. Moreover, the modifications of the PBS loop structure and dynamics that govern the annealing reaction were found strictly dependent on the integrity of the zinc finger hydrophobic platform. Our data suggest that the two NCp7 zinc fingers are required to ensure the specificity and fidelity of the second strand transfer, further underlining the pivotal role played by NCp7 to control the faithful synthesis of viral HIV-1 DNA.
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Affiliation(s)
- Julien Godet
- Laboratoire de Biophotonique et Pharmacologie, UMR 7213 CNRS, Université de Strasbourg, Faculté de Pharmacie, 74 route du Rhin, 67401 Illkirch, France
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46
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Evans JD, Peddigari S, Chaurasiya KR, Williams MC, Martin SL. Paired mutations abolish and restore the balanced annealing and melting activities of ORF1p that are required for LINE-1 retrotransposition. Nucleic Acids Res 2011; 39:5611-21. [PMID: 21441536 PMCID: PMC3141268 DOI: 10.1093/nar/gkr171] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Retrotransposition amplifies LINE-1 (L1) to high copy number in mammalian genomes. The L1 protein encoded by ORF1 (ORF1p) is required for retrotransposition. This dependence on ORF1p was investigated by mutating three highly conserved residues, R238, R284 and Y318 to alanine, thereby inactivating retrotransposition. R284A and Y318A were rescued by further substituting the alanine with the appropriate conservative amino acid, e.g. lysine or phenylalanine, respectively, whereas R238K remained inactive. Quantification of the steady-state levels of L1 RNA and ORF1p failed to discriminate active from inactive variants, indicating loss of L1 retrotransposition resulted from loss of function rather than reduced expression. The two biochemical properties known for ORF1p are high-affinity RNA binding and nucleic acid chaperone activity. Only R238A/K exhibited significantly reduced RNA affinities. The nucleic acid chaperone activities of the remaining paired mutants were assessed by single-molecule DNA stretching and found to mirror retrotransposition activity. To further examine ORF1p chaperone function, their energetic barriers to DNA annealing and melting were derived from kinetic work. When plotted against each other, the ratio of these two activities distinguished functional from non-functional ORF1p variants. These findings enhance our understanding of the requirements for ORF1p in LINE-1 retrotransposition and, more generally, nucleic acid chaperone function.
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Affiliation(s)
- James D Evans
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO 80045, USA
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Bazzi A, Zargarian L, Chaminade F, Boudier C, De Rocquigny H, René B, Mély Y, Fossé P, Mauffret O. Structural insights into the cTAR DNA recognition by the HIV-1 nucleocapsid protein: role of sugar deoxyriboses in the binding polarity of NC. Nucleic Acids Res 2011; 39:3903-16. [PMID: 21227929 PMCID: PMC3089453 DOI: 10.1093/nar/gkq1290] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
An essential step of the reverse transcription of the HIV-1 genome is the first strand transfer that requires the annealing of the TAR RNA hairpin to the cTAR DNA hairpin. HIV-1 nucleocapsid protein (NC) plays a crucial role by facilitating annealing of the complementary hairpins. Using nuclear magnetic resonance and gel retardation assays, we investigated the interaction between NC and the top half of the cTAR DNA (mini-cTAR). We show that NC(11-55) binds the TGG sequence in the lower stem that is destabilized by the adjacent internal loop. The 5′ thymine interacts with residues of the N-terminal zinc knuckle and the 3′ guanine is inserted in the hydrophobic plateau of the C-terminal zinc knuckle. The TGG sequence is preferred relative to the apical and internal loops containing unpaired guanines. Investigation of the DNA–protein contacts shows the major role of hydrophobic interactions involving nucleobases and deoxyribose sugars. A similar network of hydrophobic contacts is observed in the published NC:DNA complexes, whereas NC contacts ribose differently in NC:RNA complexes. We propose that the binding polarity of NC is related to these contacts that could be responsible for the preferential binding to single-stranded nucleic acids.
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Affiliation(s)
- Ali Bazzi
- LBPA, ENS de Cachan, CNRS, Cachan, Faculté de Pharmacie, Université de Strasbourg, 74 Route du Rhin, 67401 Illkirch, France
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Kim WY, Jung HJ, Kwak KJ, Kim MK, Oh SH, Han YS, Kang H. The Arabidopsis U12-type spliceosomal protein U11/U12-31K is involved in U12 intron splicing via RNA chaperone activity and affects plant development. THE PLANT CELL 2010; 22:3951-62. [PMID: 21148817 PMCID: PMC3027169 DOI: 10.1105/tpc.110.079103] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
U12 introns are removed from precursor-mRNA by a U12 intron-specific spliceosome that contains U11 and U12 small nuclear ribonucleoproteins. Although several proteins unique to the U12-type spliceosome have been identified, the manner by which they affect U12-dependent intron splicing as well as plant growth and development remain largely unknown. Here, we assessed the role of U11/U12-31K, a U12-type spliceosomal protein in Arabidopsis thaliana. T-DNA-tagged homozygote lines for U11/U12-31K could not be obtained, and heterozygote mutants were defective for seed maturation, indicating that U11/U12-31K is essential for the normal development of Arabidopsis. Knockdown of U11/U12-31K by artificial microRNA caused a defect in proper U12 intron splicing, resulting in abnormal stem growth and development of Arabidopsis. This defect in proper splicing was not restricted to specific U12-type introns, but most U12 intron splicing was influenced by U11/U12-31K. The stunted inflorescence stem growth was recovered by exogenously applied gibberellic acid (GA), but not by cytokinin, auxin, or brassinosteroid. GA metabolism-related genes were highly downregulated in U11/U12-31K knockdown plants. Importantly, U11/U12-31K was determined to harbor RNA chaperone activity. We propose that U11/U12-31K is an RNA chaperone that is indispensible for proper U12 intron splicing and for normal growth and development of plants.
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Abstract
Retrovirus particles in which the Gag protein has not yet been cleaved by the viral protease are termed immature particles. The viral RNA within these particles shows clear evidence of the action of a nucleic acid chaperone (NAC): the genomic RNA is dimeric, and a cellular tRNA molecule is annealed, by its 3' 18 nucleotides, to a complementary stretch in the viral RNA, in preparation for priming reverse transcription in the next round of infection. It seems very likely that the NAC that has catalyzed dimerization and tRNA annealing is the NC domain of the Gag protein itself. However, neither the dimeric linkage nor the tRNA:viral RNA complex has the same structure as those in mature virus particles: thus the conformational effects of Gag within the particles are not equivalent to those of the free NC protein present in mature particles. It is not known whether these dissimilarities reflect intrinsic differences in the NAC activities of Gag and NC, or limitations on Gag imposed by the structure of the immature particle. Analysis of the interactions of recombinant Gag proteins with nucleic acids is complicated by the fact that they result in assembly of virus-like particles. Nevertheless, the available data indicates that the affinity of Gag for nucleic acids can be considerably higher than that of free NC. This enhanced affinity may be due to contributions of the matrix domain, a positively charged region at the N-terminus of Gag; interactions of neighboring Gag molecules with each other may also increase the affinity due to cooperativity of the binding. Recombinant HIV-1 Gag protein clearly exhibits NAC activity. In two well-studied experimental systems, Gag was more efficient than NC, as its NAC effects could be detected at a significantly lower molar ratio of protein to nucleotide than with NC. In one system, binding of nucleic acid by the matrix domain of Gag retarded the Gag-induced annealing of two RNAs; this effect could be ameliorated by the competitive binding of inositol hexakisphosphate to the matrix domain.
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Affiliation(s)
- Alan Rein
- HIV Drug Resistance Program, National Cancer Institute-Frederick, Frederick, MD USA
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Martin SL. Nucleic acid chaperone properties of ORF1p from the non-LTR retrotransposon, LINE-1. RNA Biol 2010; 7:706-11. [PMID: 21045547 DOI: 10.4161/rna.7.6.13766] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Long interspersed element-1 (LINE-1, or L1) is a non-long terminal repeat (LTR) retrotransposon that has amplified to hundreds of thousands of copies in mammalian evolution. A small number of the individual copies of L1 are active retrotransposons which are presently replicating in most species, including humans and mice. L1 retrotransposition begins with transcription of an active element and ends with a newly inserted cDNA copy, a process which requires the two element-encoded proteins to act in cis on the L1 RNA. The ORF1 protein (ORF1p) is a high-affinity, non-sequence-specific RNA binding protein with nucleic acid chaperone activity, whereas the ORF2 protein (ORF2p) supplies the enzymatic activities for cDNA synthesis. This article reviews the nucleic acid chaperone properties of ORF1p in the context of L1 retrotransposition.
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Affiliation(s)
- Sandra L Martin
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO, USA.
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