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Franzo G, de Villiers L, Coetzee LM, Villiers MD, Molini U. Molecular survey of feline immunodeficiency virus (FIV) infection in Namibian cats. Acta Trop 2024; 253:107184. [PMID: 38479467 DOI: 10.1016/j.actatropica.2024.107184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Revised: 02/27/2024] [Accepted: 03/10/2024] [Indexed: 03/26/2024]
Abstract
Feline Immunodeficiency Virus (FIV) is one of the most important infectious diseases of cats, with potential implications in wildlife conservation. Unfortunately, FIV screening and surveillance in domestic cats remains limited in several African countries, including Namibia. In this study, 279 blood samples from domestic cats in Namibia were analyzed for FIV diagnosis by PCR. The cats represented various regions and were cared for by people largely from rural areas with limited financial means. Only 1.43 % of the samples tested positive, unexpectedly low given their outdoor lifestyles. The infected cats, primarily adult and unsterilized, showed no typical FIV symptoms, suggesting subclinical infections. Genetic analysis of the detected strains indicated a unique FIV strain cluster in Namibia, although with a certain within-country variability, in the absence of consistent geographical clustering. The present study represents the first detection and genetic characterization of FIV in the Namibian domestic cat population. Although the infection frequency was low, also in the rural free-roaming population, the features of the enrolled population could have biased the estimation, suggesting the need for more extensive surveys involving diseased and older cats as well. Additionally, because of the long-lasting subclinical nature of the infection, frequent monitoring activities should be performed that allow prompt isolation of infected animals and the implementation of appropriate control measures if necessary.
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Affiliation(s)
- Giovanni Franzo
- Dept. of Animal Medicine, Production and Health, University of Padova, viale dell'Università 16, Legnaro 35020, Italy.
| | - Lourens de Villiers
- School of Veterinary Medicine, Faculty of Health Sciences and Veterinary Medicine, University of Namibia, Neudamm Campus, Private Bag, Windhoek 13301, Namibia
| | - Lauren M Coetzee
- Faculty of Veterinary Medicine, University of Teramo, Teramo, Italy
| | - Mari de Villiers
- Rhino Park Veterinary Clinic, 54 Rhino Street, Windhoek North, Windhoek, Namibia
| | - Umberto Molini
- School of Veterinary Medicine, Faculty of Health Sciences and Veterinary Medicine, University of Namibia, Neudamm Campus, Private Bag, Windhoek 13301, Namibia
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Abstract
A member of the Retroviridae, human immunodeficiency virus type 1 (HIV-1), uses the RNA genome packaged into nascent virions to transfer genetic information to its progeny. The genome packaging step is a highly regulated and extremely efficient process as a vast majority of virus particles contain two copies of full-length unspliced HIV-1 RNA that form a dimer. Thus, during virus assembly HIV-1 can identify and selectively encapsidate HIV-1 unspliced RNA from an abundant pool of cellular RNAs and various spliced HIV-1 RNAs. Several "G" features facilitate the packaging of a dimeric RNA genome. The viral polyprotein Gag orchestrates virus assembly and mediates RNA genome packaging. During this process, Gag preferentially binds unpaired guanosines within the highly structured 5' untranslated region (UTR) of HIV-1 RNA. In addition, the HIV-1 unspliced RNA provides a scaffold that promotes Gag:Gag interactions and virus assembly, thereby ensuring its packaging. Intriguingly, recent studies have shown that the use of different guanosines at the junction of U3 and R as transcription start sites results in HIV-1 unspliced RNA species with 99.9% identical sequences but dramatically distinct 5' UTR conformations. Consequently, one species of unspliced RNA is preferentially packaged over other nearly identical RNAs. These studies reveal how conformations affect the functions of HIV-1 RNA elements and the complex regulation of HIV-1 replication. In this review, we summarize cis- and trans-acting elements critical for HIV-1 RNA packaging, locations of Gag:RNA interactions that mediate genome encapsidation, and the effects of transcription start sites on the structure and packaging of HIV-1 RNA.
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Affiliation(s)
- Alice Duchon
- Viral Recombination Section, HIV Dynamics and Replication Program, National Cancer Institute, Frederick, Maryland, USA
| | - Wei-Shau Hu
- Viral Recombination Section, HIV Dynamics and Replication Program, National Cancer Institute, Frederick, Maryland, USA
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3
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Godwe C, Vidal N, Muwonga J, Butel C, Serrano L, Edidi S, Ahuka-Mundeke S, Koro Koro F, Etoa X, Tongo M, Peeters M, Ayouba A. Structural Features and Genetic Diversity in Gag Gene of Rare HIV-1 Subtypes from the Democratic Republic of Congo. AIDS Res Hum Retroviruses 2024; 40:181-187. [PMID: 37335033 DOI: 10.1089/aid.2022.0154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/21/2023] Open
Abstract
Type-1 HIV (HIV-1) group M (HIV-1M) genetic diversity is highest in the Congo Basin where the epidemic ignited a century ago. HIV-1M has diversified into multiple subtypes, sub-subtypes, and circulating and unique recombinant forms (CRFs/URFs). An unanswered question is why some rare subtypes never reached epidemic levels despite their age. Several studies identified the role of HIV-1M accessory genes nef and vpu in virus adaptation to human hosts and subsequent spread. Other reports also pointed out the pivotal role of gag in transmissibility, virulence, and replication capacity. In this study we characterized the HIV-1 gag gene of 148 samples collected in different localities of the Democratic Republic of the Congo (DRC) between 1997 and 2013. We used nested polymerase chain reaction (PCR) to amplify the whole gag gene. PCR products were sequenced either by Sanger method or by next generation sequencing on Illumina MiSeq or iSeq100 platforms. Generated sequences were used for subsequent analyses using different bioinformatic tools. Phylogenetic analysis of the generated sequences revealed a high genetic diversity with up to 22 different subtypes, sub-subtypes, CRFs. Up to 15% (22/148) URFs were identified, in addition to rare subtypes such as H, J, and K. At least two amino acid motifs present in the gag gene have been shown to modulate HIV-1 replication, budding, and fitness: the P(T/S)AP and the LYPXnL motifs. Structural analysis revealed the presence of P(T/S)AP in all the 148 sequences with the majority (136/148) bearing the PTAP. Three samples presented a duplication of this motif. The LYPXnL motif was identified in 38 of 148 sequences. There was no clear link between the frequency of these motifs and HIV-1M subtypes. In summary, we confirmed a high genetic diversity of HIV-1M in the DRC. We observed the presence of amino acid motifs important for viral replication and budding even in some rare HIV-1 subtypes. Their impact on viral fitness needs be further evaluated by in vitro studies.
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Affiliation(s)
- Célestin Godwe
- Laboratoire de Virologie-Cremer, Institut de Recherches Médicales et d'Études des Plantes Médicinales (IMPM), Yaoundé, Cameroon
- Department of Biochemistry, Faculty of Sciences, University of Douala, Douala, Cameroon
| | - Nicole Vidal
- TransVIHMI, Université de Montpellier, IRD, INSERM, Montpellier, France
| | - Jérémie Muwonga
- National AIDS Control Program, Kinshasa, Democratic Republic of the Congo
| | - Christelle Butel
- TransVIHMI, Université de Montpellier, IRD, INSERM, Montpellier, France
| | - Laetitia Serrano
- TransVIHMI, Université de Montpellier, IRD, INSERM, Montpellier, France
| | - Samuel Edidi
- National AIDS Control Program, Kinshasa, Democratic Republic of the Congo
| | - Steve Ahuka-Mundeke
- Department of Virology, Institut National de Recherche Biomédicale, Kinshasa, Democratic Republic of the Congo
- Service de Microbiologie, Département de Biologie Médicale, Cliniques Universitaires de Kinshasa, Université de Kinshasa, Kinshasa, Democratic Republic of the Congo
| | - Francioli Koro Koro
- Department of Biochemistry, Faculty of Sciences, University of Douala, Douala, Cameroon
| | - Xavier Etoa
- Department of Microbiology, Faculty of Sciences, University of Yaoundé I, Yaoundé, Cameroon
| | - Marcel Tongo
- Laboratoire de Virologie-Cremer, Institut de Recherches Médicales et d'Études des Plantes Médicinales (IMPM), Yaoundé, Cameroon
| | - Martine Peeters
- TransVIHMI, Université de Montpellier, IRD, INSERM, Montpellier, France
| | - Ahidjo Ayouba
- Laboratoire de Virologie-Cremer, Institut de Recherches Médicales et d'Études des Plantes Médicinales (IMPM), Yaoundé, Cameroon
- TransVIHMI, Université de Montpellier, IRD, INSERM, Montpellier, France
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4
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Xu J, Erlendsson S, Singh M, Holling GA, Regier M, Ibiricu I, Einstein J, Hantak MP, Day GS, Piquet AL, Smith TL, Clardy SL, Whiteley AM, Feschotte C, Briggs JAG, Shepherd JD. PNMA2 forms immunogenic non-enveloped virus-like capsids associated with paraneoplastic neurological syndrome. Cell 2024; 187:831-845.e19. [PMID: 38301645 PMCID: PMC10922747 DOI: 10.1016/j.cell.2024.01.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 09/20/2023] [Accepted: 01/05/2024] [Indexed: 02/03/2024]
Abstract
The paraneoplastic Ma antigen (PNMA) proteins are associated with cancer-induced paraneoplastic syndromes that present with an autoimmune response and neurological symptoms. Why PNMA proteins are associated with this severe autoimmune disease is unclear. PNMA genes are predominantly expressed in the central nervous system and are ectopically expressed in some tumors. We show that PNMA2, which has been co-opted from a Ty3 retrotransposon, encodes a protein that is released from cells as non-enveloped virus-like capsids. Recombinant PNMA2 capsids injected into mice induce autoantibodies that preferentially bind external "spike" PNMA2 capsid epitopes, whereas a capsid-assembly-defective PNMA2 protein is not immunogenic. PNMA2 autoantibodies in cerebrospinal fluid of patients with anti-Ma2 paraneoplastic disease show similar preferential binding to spike capsid epitopes. PNMA2 capsid-injected mice develop learning and memory deficits. These observations suggest that PNMA2 capsids act as an extracellular antigen, capable of generating an autoimmune response that results in neurological deficits.
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Affiliation(s)
- Junjie Xu
- Department of Neurobiology, University of Utah, Salt Lake City, UT, USA
| | - Simon Erlendsson
- The Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, UK; Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Copenhagen, Denmark
| | - Manvendra Singh
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
| | - G Aaron Holling
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA
| | - Matthew Regier
- Department of Neurobiology, University of Utah, Salt Lake City, UT, USA
| | - Iosune Ibiricu
- Department of Cell and Virus Structure, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Jenifer Einstein
- Department of Neurobiology, University of Utah, Salt Lake City, UT, USA
| | - Michael P Hantak
- Department of Neurobiology, University of Utah, Salt Lake City, UT, USA
| | - Gregory S Day
- Department of Neurology, Mayo Clinic, Jacksonville, FL, USA
| | - Amanda L Piquet
- Department of Neurology, University of Colorado, Aurora, CO, USA
| | - Tammy L Smith
- Department of Neurology, University of Utah and George E Wahlen VA Medical Center, Salt Lake City, UT, USA
| | - Stacey L Clardy
- Department of Neurology, University of Utah and George E Wahlen VA Medical Center, Salt Lake City, UT, USA
| | | | - Cédric Feschotte
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
| | - John A G Briggs
- The Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, UK; Department of Cell and Virus Structure, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Jason D Shepherd
- Department of Neurobiology, University of Utah, Salt Lake City, UT, USA.
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5
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Arone C, Martial S, Burlaud-Gaillard J, Thoulouze MI, Roingeard P, Dutartre H, Muriaux D. HTLV-1 biofilm polarization maintained by tetraspanin CD82 is required for efficient viral transmission. mBio 2023; 14:e0132623. [PMID: 37889017 PMCID: PMC10746275 DOI: 10.1128/mbio.01326-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Accepted: 09/11/2023] [Indexed: 10/28/2023] Open
Abstract
The human T-lymphotropic virus type 1 (HTLV-1) is an oncogenic retrovirus whose transmission relies primarily on cell-to-cell contacts as cell-free viruses are poorly infectious. Among the intercellular transmission routes described, HTLV-1 biofilms are adhesive structures polarized at the cell surface that confine virions in a protective environment, which is believed to promote their simultaneous delivery during infection. Here, we show that several tetraspanins are enriched in HTLV-1 biofilms and incorporated into the viral envelope. However, we report that only the tetraspanin CD82 interacts with HTLV-1 Gag proteins which initiates their polarization into viral biofilms. Also, we demonstrate that CD82 maintains HTLV-1 biofilm polarization and favors viral transmission, as its silencing induces a complete reorganization of viral clusters at the cell surface and reduces the ability of infected T-cells to transmit the virus. Our results highlight the crucial role of CD82 and its glycosylation state in the architectural organization of HTLV-1 biofilms and their subsequent transfer through intercellular contacts.IMPORTANCEIn the early stages of infection, human T-lymphotropic virus type 1 (HTLV-1) dissemination within its host is believed to rely mostly on cell-to-cell contacts. Past studies unveiled a novel mechanism of HTLV-1 intercellular transmission based on the remodeling of the host-cell extracellular matrix and the generation of cell-surface viral assemblies whose structure, composition, and function resemble bacterial biofilms. These polarized aggregates of infectious virions, identified as viral biofilms, allow the bulk delivery of viruses to target cells and may help to protect virions from immune attacks. However, viral biofilms' molecular and functional description is still in its infancy, although it is crucial to fully decipher retrovirus pathogenesis. Here, we explore the function of cellular tetraspanins (CD9, CD81, CD82) that we detect inside HTLV-1 particles within biofilms. Our results demonstrate specific roles for CD82 in the cell-surface distribution and intercellular transmission of HTLV-1 biofilms, which we document as two essential parameters for efficient viral transmission. At last, our findings indicate that N-glycosylation of cell-surface molecules, including CD82, is required for the polarization of HTLV-1 biofilms and for the efficient transmission of HTLV-1 between T-lymphocytes.
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Affiliation(s)
- Coline Arone
- Infectious Disease Research Institute of Montpellier (IRIM), UMR CNRS, Montpellier, France
| | - Samuel Martial
- Center for International Research on Infectiology (CIRI), UMR Inserm, Lyon, France
| | | | | | - Philippe Roingeard
- IBiSA Electron Microscopy Platform of Tours University, UMR Inserm, Tours, France
| | - Hélène Dutartre
- Center for International Research on Infectiology (CIRI), UMR Inserm, Lyon, France
| | - Delphine Muriaux
- Infectious Disease Research Institute of Montpellier (IRIM), UMR CNRS, Montpellier, France
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6
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Liu Q, Yu YY, Wang HY. Differences in CpG island distribution between exogenous and endogenous jaagsiekte sheep retrovirus strains. Vet Res Forum 2023; 14:531-539. [PMID: 37901353 PMCID: PMC10612397 DOI: 10.30466/vrf.2022.552748.3454] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Accepted: 10/16/2022] [Indexed: 10/31/2023]
Abstract
The jaagsiekte sheep retrovirus (JSRV), belonging to the betaretrovirus genus of the retroviridae family, includes both exogenous and endogenous jaagsiekte sheep retroviruses (exJSRV and enJSRV, respectively). At the proviral genome level, exJSRV and enJSRV strains have a high degree of similarity with their main variation regions being the LTR, gag, and env genes. In this study, for the first time, we investigated and compared the distribution of CpG islands between these enJSRV and exJSRV strains. Specifically, we analyzed a total of 42 full-length JSRV genomic sequences obtained from the GenBank® database to identify CpG islands in the exJSRV and enJSRV genomes using the MethPrimer software. Our results showed that the CpG islands in the two JSRV strains were mainly distributed in the LTR, gag, and env genes. In exJSRVs, 66.66% (6/9), 33.33% (3/9), and 100% (9/9) of the sequences presented at least one CpG island in LTR, gag, env genes, respectively, and for enJSRVs, 84.84% (28/33), 57.57% (19/33), and 96.96% (32/33) of the sequences presented at least one CpG island in the LTR, gag, and env genes. These findings suggested that the distribution, length, and genetic traits of CpG islands were different for the exJSRV and enJSRV strains. In future, it would be necessary to demonstrate the biological significance of CpG islands within these genes in exJSRV and enJSRV genomes. This will enhance understanding regarding the potential role of CpG islands in epigenetic regulation.
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Affiliation(s)
- Qiang Liu
- Department of Agricultural Science and Technology, Nanchong Vocational and Technical College, Nanchong, China.
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Obr M, Percipalle M, Chernikova D, Yang H, Thader A, Pinke G, Porley D, Mansky LM, Dick RA, Schur FKM. Unconventional stabilization of the human T-cell leukemia virus type 1 immature Gag lattice. bioRxiv 2023:2023.07.24.548988. [PMID: 37546793 PMCID: PMC10402013 DOI: 10.1101/2023.07.24.548988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
Human T-cell leukemia virus type 1 (HTLV-1) has an atypical immature particle morphology compared to other retroviruses. This indicates that these particles are formed in a way that is unique. Here we report the results of cryo-electron tomography (cryo-ET) studies of HTLV-1 virus-like particles (VLPs) assembled in vitro, as well as derived from cells. This work shows that HTLV-1 employs an unconventional mechanism of Gag-Gag interactions to form the immature viral lattice. Analysis of high-resolution structural information from immature CA tubular arrays reveals that the primary stabilizing component in HTLV-1 is CA-NTD. Mutagenesis and biophysical analysis support this observation. This distinguishes HTLV-1 from other retroviruses, in which the stabilization is provided primarily by the CA-CTD. These results are the first to provide structural details of the quaternary arrangement of Gag for an immature deltaretrovirus, and this helps explain why HTLV-1 particles are morphologically distinct.
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Affiliation(s)
- Martin Obr
- Institute of Science and Technology Austria (ISTA), Klosterneuburg, Austria
| | - Mathias Percipalle
- Institute of Science and Technology Austria (ISTA), Klosterneuburg, Austria
| | - Darya Chernikova
- Institute of Science and Technology Austria (ISTA), Klosterneuburg, Austria
| | - Huixin Yang
- Institute for Molecular Virology, University of Minnesota, Minneapolis, MN, USA
| | - Andreas Thader
- Institute of Science and Technology Austria (ISTA), Klosterneuburg, Austria
| | - Gergely Pinke
- Institute of Science and Technology Austria (ISTA), Klosterneuburg, Austria
| | - Dario Porley
- Institute of Science and Technology Austria (ISTA), Klosterneuburg, Austria
| | - Louis M Mansky
- Institute for Molecular Virology, University of Minnesota, Minneapolis, MN, USA
| | - Robert A Dick
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
| | - Florian KM Schur
- Institute of Science and Technology Austria (ISTA), Klosterneuburg, Austria
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Jeewanraj N, Mandizvo T, Mulaudzi T, Gumede N, Ndhlovu Z, Ndung'u T, Gounder K, Mann J. Partial compartmentalisation of HIV-1 subtype C between lymph nodes, peripheral blood mononuclear cells and plasma. Virology 2023; 582:62-70. [PMID: 37030154 PMCID: PMC10132742 DOI: 10.1016/j.virol.2023.03.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 03/10/2023] [Accepted: 03/22/2023] [Indexed: 04/03/2023]
Abstract
HIV-1 compartmentalisation is likely to have important implications for a preventative vaccine as well as eradication strategies. We genetically characterised HIV-1 subtype C variants in lymph nodes, peripheral blood mononuclear cells and plasma of six antiretroviral (ART) naïve individuals and four individuals on ART. Full-length env (n = 171) and gag (n = 250) sequences were generated from participants using single genome amplification. Phylogenetic relatedness of sequences was assessed, and compartmentalisation was determined using both distance and tree-based methods implemented in HyPhy. Additionally, potential associations between compartmentalisation and immune escape mutations were assessed. Partial viral compartmentalisation was present in nine of the ten participants. Broadly neutralising antibody (bnAb) escape was found to be associated with partial env compartmentalisation in some individuals, while cytotoxic T lymphocyte escape mutations in Gag were limited and did not differ between compartments. Viral compartmentalisation may be an important consideration for bnAb use in viral eradication.
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Affiliation(s)
- Neschika Jeewanraj
- HIV Pathogenesis Programme, Doris Duke Medical Research Institute, Nelson R. Mandela School of Medicine, University of KwaZulu-Natal, Durban, South Africa
| | - Tawanda Mandizvo
- HIV Pathogenesis Programme, Doris Duke Medical Research Institute, Nelson R. Mandela School of Medicine, University of KwaZulu-Natal, Durban, South Africa; Africa Health Research Institute, Durban, South Africa
| | - Takalani Mulaudzi
- HIV Pathogenesis Programme, Doris Duke Medical Research Institute, Nelson R. Mandela School of Medicine, University of KwaZulu-Natal, Durban, South Africa
| | - Nombali Gumede
- HIV Pathogenesis Programme, Doris Duke Medical Research Institute, Nelson R. Mandela School of Medicine, University of KwaZulu-Natal, Durban, South Africa
| | - Zaza Ndhlovu
- HIV Pathogenesis Programme, Doris Duke Medical Research Institute, Nelson R. Mandela School of Medicine, University of KwaZulu-Natal, Durban, South Africa; Africa Health Research Institute, Durban, South Africa; Ragon Institute of Massachusetts General Hospital, Massachusetts Institute of Technology and Harvard University, Cambridge, MA, USA
| | - Thumbi Ndung'u
- HIV Pathogenesis Programme, Doris Duke Medical Research Institute, Nelson R. Mandela School of Medicine, University of KwaZulu-Natal, Durban, South Africa; Africa Health Research Institute, Durban, South Africa; Ragon Institute of Massachusetts General Hospital, Massachusetts Institute of Technology and Harvard University, Cambridge, MA, USA; Division of Infection and Immunity, University College London, London, United Kingdom
| | - Kamini Gounder
- HIV Pathogenesis Programme, Doris Duke Medical Research Institute, Nelson R. Mandela School of Medicine, University of KwaZulu-Natal, Durban, South Africa; Africa Health Research Institute, Durban, South Africa
| | - Jaclyn Mann
- HIV Pathogenesis Programme, Doris Duke Medical Research Institute, Nelson R. Mandela School of Medicine, University of KwaZulu-Natal, Durban, South Africa.
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Rawson JMO, Nikolaitchik OA, Yoo JA, Somoulay X, Brown MA, Mbuntcha Bogni FS, Pathak VK, Soheilian F, Slack RL, Sarafianos SG, Hu WS. Adaptation of HIV-1/HIV-2 Chimeras with Defects in Genome Packaging and Viral Replication. mBio 2022; 13:e0222022. [PMID: 36036631 DOI: 10.1128/mbio.02220-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Frequent recombination is a hallmark of retrovirus replication. In rare cases, recombination occurs between distantly related retroviruses, generating novel viruses that may significantly impact viral evolution and public health. These recombinants may initially have substantial replication defects due to impaired interactions between proteins and/or nucleic acids from the two parental viruses. However, given the high mutation rates of retroviruses, these recombinants may be able to evolve improved compatibility of these viral elements. To test this hypothesis, we examined the adaptation of chimeras between two distantly related human pathogens: HIV-1 and HIV-2. We constructed HIV-1-based chimeras containing the HIV-2 nucleocapsid (NC) domain of Gag or the two zinc fingers of HIV-2 NC, which are critical for specific recognition of viral RNA. These chimeras exhibited significant defects in RNA genome packaging and replication kinetics in T cells. However, in some experiments, the chimeric viruses replicated with faster kinetics when repassaged, indicating that viral adaptation had occurred. Sequence analysis revealed the acquisition of a single amino acid substitution, S18L, in the first zinc finger of HIV-2 NC. This substitution, which represents a switch from a conserved HIV-2 residue to a conserved HIV-1 residue at this position, partially rescued RNA packaging and replication kinetics. Further analysis revealed that the combination of two substitutions in HIV-2 NC, W10F and S18L, almost completely restored RNA packaging and replication kinetics. Our study demonstrates that chimeras of distantly related retroviruses can adapt and significantly enhance their replication by acquiring a single substitution. IMPORTANCE Novel retroviruses can emerge from recombination between distantly related retroviruses. Most notably, HIV-1 originated from zoonotic transmission of a novel recombinant (SIVcpz) into humans. Newly generated recombinants may initially have significant replication defects due to impaired interactions between viral proteins and/or nucleic acids, such as between cis- and trans-acting elements from the two parental viruses. However, provided that the recombinants retain some ability to replicate, they may be able to adapt and repair the defective interactions. Here, we used HIV-1 and HIV-2 Gag chimeras as a model system for studying the adaptation of recombinant viruses. We found that only two substitutions in the HIV-2 NC domain, W10F and S18L, were required to almost fully restore RNA genome packaging and replication kinetics. These results illustrate the extremely flexible nature of retroviruses and highlight the possible emergence of novel recombinants in the future that could pose a significant threat to public health.
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10
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Zawadzka M, Andrzejewska-Romanowska A, Gumna J, Garfinkel DJ, Pachulska-Wieczorek K. Cell Compartment-Specific Folding of Ty1 Long Terminal Repeat Retrotransposon RNA Genome. Viruses 2022; 14:2007. [PMID: 36146813 PMCID: PMC9503155 DOI: 10.3390/v14092007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 09/01/2022] [Accepted: 09/08/2022] [Indexed: 11/16/2022] Open
Abstract
The structural transitions RNAs undergo during trafficking are not well understood. Here, we used the well-developed yeast Ty1 retrotransposon to provide the first structural model of genome (g) RNA in the nucleus from a retrovirus-like transposon. Through a detailed comparison of nuclear Ty1 gRNA structure with those established in the cytoplasm, virus-like particles (VLPs), and those synthesized in vitro, we detected Ty1 gRNA structural alterations that occur during retrotransposition. Full-length Ty1 gRNA serves as the mRNA for Gag and Gag-Pol proteins and as the genome that is reverse transcribed within VLPs. We show that about 60% of base pairs predicted for the nuclear Ty1 gRNA appear in the cytoplasm, and active translation does not account for such structural differences. Most of the shared base pairs are represented by short-range interactions, whereas the long-distance pairings seem unique for each compartment. Highly structured motifs tend to be preserved after nuclear export of Ty1 gRNA. In addition, our study highlights the important role of Ty1 Gag in mediating critical RNA-RNA interactions required for retrotransposition.
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Affiliation(s)
- Małgorzata Zawadzka
- Department of Structure and Function of Retrotransposons, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
| | - Angelika Andrzejewska-Romanowska
- Department of Structure and Function of Retrotransposons, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
| | - Julita Gumna
- Department of Structure and Function of Retrotransposons, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
| | - David J. Garfinkel
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - Katarzyna Pachulska-Wieczorek
- Department of Structure and Function of Retrotransposons, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
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11
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Samal AB, Green TJ, Saad JS. Atomic view of the HIV-1 matrix lattice; implications on virus assembly and envelope incorporation. Proc Natl Acad Sci U S A 2022; 119:e2200794119. [PMID: 35658080 DOI: 10.1073/pnas.2200794119] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
SignificanceThe assembly of immature HIV-1 particles is initiated by targeting of the Gag polyproteins to the plasma membrane (PM). Gag binding to the PM is mediated by the N-terminally myristoylated matrix (myrMA) domain. Formation of a Gag lattice on the PM is obligatory for the assembly of immature HIV-1 and envelope (Env) incorporation. The structure of the myrMA lattice presented here provided insights on the molecular factors that stabilize the lattice and hence favor Env incorporation. Our data support a mechanism for Gag binding to the PM during the assembly of immature particles and upon maturation. These findings advance our understanding of a critical step in HIV-1 assembly.
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12
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Climaco-Arvizu S, Flores-López V, González-Torres C, Gaytán-Cervantes FJ, Hernández-García MC, Zárate-Segura PB, Chávez-Torres M, Tesoro-Cruz E, Pinto-Cardoso SM, Bekker-Méndez VC. Protease and gag diversity and drug resistance mutations among treatment-naive Mexican people living with HIV. BMC Infect Dis 2022; 22:447. [PMID: 35538426 PMCID: PMC9088029 DOI: 10.1186/s12879-022-07446-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Accepted: 04/29/2022] [Indexed: 08/30/2023] Open
Abstract
Introduction In Mexico, HIV genotyping is performed in people living with HIV (PLWH) failing their first-line antiretroviral (ARV) regimen; it is not routinely done for all treatment-naive PLWH before ARV initiation. The first nationally representative survey published in 2016 reported that the prevalence of pretreatment drug mutations in treatment-naive Mexican PLWH was 15.5% to any antiretroviral drug and 10.6% to non-nucleoside reverse transcriptase inhibitors (NNRTIs) using conventional Sanger sequencing. Most reports in Mexico focus on HIV pol gene and nucleoside and non-nucleoside reverse transcriptase inhibitor (NRTI and NNRTI) drug resistance mutations (DRMs) prevalence, using Sanger sequencing, next-generation sequencing (NGS) or both. To our knowledge, NGS has not be used to detect pretreatment drug resistance mutations (DRMs) in the HIV protease (PR) gene and its substrate the Gag polyprotein. Methods Treatment-naive adult Mexican PLWH were recruited between 2016 and 2019. HIV Gag and protease sequences were obtained by NGS and DRMs were identified using the WHO surveillance drug resistance mutation (SDRM) list. Results One hundred PLWH attending a public national reference hospital were included. The median age was 28 years-old, and most were male. The median HIV viral load was 4.99 [4.39–5.40] log copies/mL and median CD4 cell count was 150 [68.0–355.78] cells/mm3. As expected, most sequences clustered with HIV-1 subtype B (97.9%). Major PI resistance mutations were detected: 8 (8.3%) of 96 patients at a detection threshold of 1% and 3 (3.1%) at a detection threshold of 20%. A total of 1184 mutations in Gag were detected, of which 51 have been associated with resistance to PI, most of them were detected at a threshold of 20%. Follow-up clinical data was available for 79 PLWH at 6 months post-ART initiation, seven PLWH failed their first ART regimen; however no major PI mutations were identified in these individuals at baseline. Conclusions The frequency of DRM in the HIV protease was 7.3% at a detection threshold of 1% and 3.1% at a detection threshold of 20%. NGS-based HIV drug resistance genotyping provide improved detection of DRMs. Viral load was used to monitor ARV response and treatment failure was 8.9%. Supplementary Information The online version contains supplementary material available at 10.1186/s12879-022-07446-8.
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Affiliation(s)
- Samantha Climaco-Arvizu
- Unidad de Investigación Médica en Inmunología e Infectología, Hospital de Infectología "Dr Daniel Méndez Hernández", Centro Médico Nacional "La Raza", Instituto Mexicano del Seguro Social (IMSS), Ciudad de México, C.P. 02990, México.,Laboratorio de Medicina Traslacional, Instituto Politécnico Nacional, Ciudad de México, México
| | | | - Carolina González-Torres
- División de Desarrollo de La Investigación, Instituto Mexicano del Seguro Social, Ciudad de México, México
| | | | - María Concepción Hernández-García
- Instituto Mexicano del Seguro Social (IMSS), Hospital de Infectología "Dr Daniel Méndez Hernández", Centro Médico Nacional (CMN), La Raza", Ciudad de México, México
| | | | - Monserrat Chávez-Torres
- Centro de Investigación en Enfermedades Infecciosas, Instituto Nacional de Enfermedades Respiratorias Ismael Cosío Villegas, Ciudad de México, C.P. 14080, México
| | - Emiliano Tesoro-Cruz
- Unidad de Investigación Médica en Inmunología e Infectología, Hospital de Infectología "Dr Daniel Méndez Hernández", Centro Médico Nacional "La Raza", Instituto Mexicano del Seguro Social (IMSS), Ciudad de México, C.P. 02990, México
| | - Sandra María Pinto-Cardoso
- Centro de Investigación en Enfermedades Infecciosas, Instituto Nacional de Enfermedades Respiratorias Ismael Cosío Villegas, Ciudad de México, C.P. 14080, México.
| | - Vilma Carolina Bekker-Méndez
- Unidad de Investigación Médica en Inmunología e Infectología, Hospital de Infectología "Dr Daniel Méndez Hernández", Centro Médico Nacional "La Raza", Instituto Mexicano del Seguro Social (IMSS), Ciudad de México, C.P. 02990, México.
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13
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Evans EL, Pocock GM, Einsdorf G, Behrens RT, Dobson ETA, Wiedenmann M, Birkhold C, Ahlquist P, Eliceiri KW, Sherer NM. HIV RGB: Automated Single-Cell Analysis of HIV-1 Rev-Dependent RNA Nuclear Export and Translation Using Image Processing in KNIME. Viruses 2022; 14:903. [PMID: 35632645 PMCID: PMC9145009 DOI: 10.3390/v14050903] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 04/21/2022] [Accepted: 04/23/2022] [Indexed: 01/27/2023] Open
Abstract
Single-cell imaging has emerged as a powerful means to study viral replication dynamics and identify sites of virus−host interactions. Multivariate aspects of viral replication cycles yield challenges inherent to handling large, complex imaging datasets. Herein, we describe the design and implementation of an automated, imaging-based strategy, “Human Immunodeficiency Virus Red-Green-Blue” (HIV RGB), for deriving comprehensive single-cell measurements of HIV-1 unspliced (US) RNA nuclear export, translation, and bulk changes to viral RNA and protein (HIV-1 Rev and Gag) subcellular distribution over time. Differentially tagged fluorescent viral RNA and protein species are recorded using multicolor long-term (>24 h) time-lapse video microscopy, followed by image processing using a new open-source computational imaging workflow dubbed “Nuclear Ring Segmentation Analysis and Tracking” (NR-SAT) based on ImageJ plugins that have been integrated into the Konstanz Information Miner (KNIME) analytics platform. We describe a typical HIV RGB experimental setup, detail the image acquisition and NR-SAT workflow accompanied by a step-by-step tutorial, and demonstrate a use case wherein we test the effects of perturbing subcellular localization of the Rev protein, which is essential for viral US RNA nuclear export, on the kinetics of HIV-1 late-stage gene regulation. Collectively, HIV RGB represents a powerful platform for single-cell studies of HIV-1 post-transcriptional RNA regulation. Moreover, we discuss how similar NR-SAT-based design principles and open-source tools might be readily adapted to study a broad range of dynamic viral or cellular processes.
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Affiliation(s)
- Edward L. Evans
- McArdle Laboratory for Cancer Research (Department of Oncology), Institute for Molecular Virology, and Carbone Cancer Center, University of Wisconsin-Madison, Madison, WI 53706, USA; (E.L.E.III); (G.M.P.); (R.T.B.)
- Laboratory for Optical and Computational Instrumentation, Center for Quantitative Cell Imaging, University of Wisconsin-Madison, Madison, WI 53706, USA; (G.E.); (E.T.A.D.); (M.W.)
- Morgridge Institute for Research, Madison, WI 53715, USA
| | - Ginger M. Pocock
- McArdle Laboratory for Cancer Research (Department of Oncology), Institute for Molecular Virology, and Carbone Cancer Center, University of Wisconsin-Madison, Madison, WI 53706, USA; (E.L.E.III); (G.M.P.); (R.T.B.)
- Laboratory for Optical and Computational Instrumentation, Center for Quantitative Cell Imaging, University of Wisconsin-Madison, Madison, WI 53706, USA; (G.E.); (E.T.A.D.); (M.W.)
- Morgridge Institute for Research, Madison, WI 53715, USA
| | - Gabriel Einsdorf
- Laboratory for Optical and Computational Instrumentation, Center for Quantitative Cell Imaging, University of Wisconsin-Madison, Madison, WI 53706, USA; (G.E.); (E.T.A.D.); (M.W.)
- KNIME GmbH, 78467 Konstanz, Germany;
| | - Ryan T. Behrens
- McArdle Laboratory for Cancer Research (Department of Oncology), Institute for Molecular Virology, and Carbone Cancer Center, University of Wisconsin-Madison, Madison, WI 53706, USA; (E.L.E.III); (G.M.P.); (R.T.B.)
| | - Ellen T. A. Dobson
- Laboratory for Optical and Computational Instrumentation, Center for Quantitative Cell Imaging, University of Wisconsin-Madison, Madison, WI 53706, USA; (G.E.); (E.T.A.D.); (M.W.)
| | - Marcel Wiedenmann
- Laboratory for Optical and Computational Instrumentation, Center for Quantitative Cell Imaging, University of Wisconsin-Madison, Madison, WI 53706, USA; (G.E.); (E.T.A.D.); (M.W.)
- KNIME GmbH, 78467 Konstanz, Germany;
| | | | - Paul Ahlquist
- McArdle Laboratory for Cancer Research (Department of Oncology), Institute for Molecular Virology, and Carbone Cancer Center, University of Wisconsin-Madison, Madison, WI 53706, USA; (E.L.E.III); (G.M.P.); (R.T.B.)
- Morgridge Institute for Research, Madison, WI 53715, USA
- John and Jeanne Rowe Center for Research in Virology, Madison, WI 53715, USA
| | - Kevin W. Eliceiri
- Laboratory for Optical and Computational Instrumentation, Center for Quantitative Cell Imaging, University of Wisconsin-Madison, Madison, WI 53706, USA; (G.E.); (E.T.A.D.); (M.W.)
- Morgridge Institute for Research, Madison, WI 53715, USA
| | - Nathan M. Sherer
- McArdle Laboratory for Cancer Research (Department of Oncology), Institute for Molecular Virology, and Carbone Cancer Center, University of Wisconsin-Madison, Madison, WI 53706, USA; (E.L.E.III); (G.M.P.); (R.T.B.)
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14
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Li M, Yuan Y, Li P, Deng Z, Wen Z, Wang H, Feng F, Zou H, Chen L, Tang S, Sun C. Comparison of the Immunogenicity of HIV-1 CRF07_BC Gag Antigen With or Without a Seven Amino Acid Deletion in p6 Region. Front Immunol 2022; 13:850719. [PMID: 35450078 PMCID: PMC9017423 DOI: 10.3389/fimmu.2022.850719] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2022] [Accepted: 03/03/2022] [Indexed: 11/23/2022] Open
Abstract
HIV-1 CRF07_BC-p6Δ7, a strain with a seven amino acid deletion in the p6 region of the Gag protein, is becoming the dominant strain of HIV transmission among men who have sex with men (MSM) in China. Previous studies demonstrated that HIV-1 patients infected by CRF07_BC-p6Δ7 strain had lower viral load and slower disease progression than those patients infected with CRF07_BC wild-type strain. However, the underlying mechanism for this observation is not fully clarified yet. In this study, we constructed the recombinant DNA plasmid and adenovirus type 2 (Ad2) vector-based constructs to express the HIV-1 CRF07_BC Gag antigen with or without p6Δ7 mutation and then investigated their immunogenicity in mice. Our results showed that HIV-1 CRF07_BC Gag antigen with p6Δ7 mutation induced a comparable level of Gag-specific antibodies but stronger CD4+ and CD8+ T-cell immune responses than that of CRF07_BC Gag (07_BC-wt). Furthermore, we identified a series of T-cell epitopes, which induced strong T-cell immune response and cross-immunity with CRF01_AE Gag. These findings implied that the p6Gag protein with a seven amino acid deletion might enhance the Gag immunogenicity in particular cellular immunity, which provides valuable information to clarify the pathogenic mechanism of HIV-1 CRF07_BC-p6Δ7 and to develop precise vaccine strategies against HIV-1 infection.
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Affiliation(s)
- Minchao Li
- School of Public Health (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Shenzhen, China
| | - Yue Yuan
- School of Public Health (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Shenzhen, China
| | - Pingchao Li
- State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health (GIBH), Chinese Academy of Sciences, Guangzhou, China
| | - Zhaomin Deng
- School of Public Health (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Shenzhen, China
| | - Ziyu Wen
- School of Public Health (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Shenzhen, China
| | - Haiying Wang
- Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou, China
| | - Fengling Feng
- School of Public Health (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Shenzhen, China
| | - Huachun Zou
- School of Public Health (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Shenzhen, China
| | - Ling Chen
- State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health (GIBH), Chinese Academy of Sciences, Guangzhou, China
| | - Shixing Tang
- Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou, China
| | - Caijun Sun
- School of Public Health (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Shenzhen, China.,Key Laboratory of Tropical Disease Control (Sun Yat-Sen University), Ministry of Education, Guangzhou, China
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Zhang J, Han C, Xiong Z, Qiu M, Tuo X, Wang C, Qiao W, Tan J. SGK1, a Serine/Threonine Kinase, Inhibits Prototype Foamy Virus Replication. Microbiol Spectr 2022;:e0199521. [PMID: 35438526 DOI: 10.1128/spectrum.01995-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Foamy viruses (FVs) are complex retroviruses belonging to the Spumaretrovirinae subfamily of the Retroviridae family. In contrast to human immunodeficiency virus (HIV), another member of the Retroviridae family, FVs are nonpathogenic in their natural hosts or in experimentally infected animals. Prototype foamy virus (PFV) is the only foamy virus that can infect humans through cross-species transmission and does not show any pathogenicity after infection. Consequently, PFV is considered a safe and efficient gene transfer vector. Understanding the host proteins involved in the replication of PFV and the mechanism of interaction between the host and the virus might lead to studies to improve the efficiency of gene transfer. To date, only a few host factors have been identified that affect PFV replication. In the present study, we report that PFV infection enhances the promoter activity of SGK1 (encoding serum/glucocorticoid regulated kinase 1) via the Tas protein signaling pathway, and then upregulates the mRNA and protein levels of SGK1. Overexpression of SGK1 reduced PFV replication, whereas its depletion using small interfering RNA increased PFV replication. SGK1 inhibits PFV replication by impairing the function of the PFV Tas activation domain in a kinase-independent manner and reducing the stability of the Gag protein in a kinase-dependent manner. In addition, both human and bovine SGK1 proteins inhibit the replication of bovine foamy virus (BFV) and PFV. These findings not only improved our understanding of the function of SGK1 and its relationship with foamy viruses, but also contributed to determining the antiviral mechanism of the host. IMPORTANCE Foamy viruses can integrate into the host chromosome and are nonpathogenic in natural hosts or in experimentally infected animals. Therefore, foamy viruses are considered to be safe and efficient gene transfer vectors. Persistent infection of foamy viruses is partly caused by the restrictive effect of host factors on the virus. However, only a few cellular proteins are known to influence the replication of foamy viruses. In this study, we report that SGK1 inhibits the replication of prototype foamy virus by affecting the function of the transcription activator, Tas, and reducing the stability of the structural protein, Gag. These results will increase our understanding of the interaction between the virus and host factors, deepening our perception of host antiviral defenses and the function of SGK1, and could improve the gene transfer efficiency of foamy viruses.
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Abstract
BACKGROUND HIV-1 pol, which encodes enzymes required for virus replication, is initially translated as a Gag-Pol fusion protein. Gag-Pol is incorporated into virions via interactions with Gag precursor Pr55gag. Protease (PR) embedded in Gag-Pol mediates the proteolytic processing of both Pr55gag and Gag-Pol during or soon after virus particle release from cells. Since efficient Gag-Pol viral incorporation depends on interaction with Pr55gag via its N-terminal Gag domain, the prevention of premature Gag cleavage may alleviate Gag-Pol packaging deficiencies associated with cleavage enhancement from PR. RESULTS We engineered PR cleavage-blocking Gag mutations with the potential to significantly reduce Gag processing efficiency. Such mutations may mitigate the negative effects of enhanced PR activation on virus assembly and Gag-Pol packaging due to an RT dimerization enhancer or leucine zipper dimerization motif. When co-expressed with Pr55gag, we noted that enhanced PR activation resulted in reduced Gag-Pol cis or trans incorporation into Pr55gag particles, regardless of whether or not Gag cleavage sites within Gag-Pol were blocked. CONCLUSIONS Our data suggest that the amount of HIV-1 Gag-Pol or Pol viral incorporation is largely dependent on virus particle production, and that cleavage blocking in the Gag-Pol N-terminal Gag domain does not exert significant impacts on Pol packaging.
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Affiliation(s)
- Yi-Ru Lin
- Institute of Clinical Medicine, National Yang Ming Chiao Tung University School of Medicine, 112, Taipei, Taiwan
| | - Shih-Ming Chu
- Institute of Clinical Medicine, National Yang Ming Chiao Tung University School of Medicine, 112, Taipei, Taiwan
| | - Fu-Hsien Yu
- Institute of Clinical Medicine, National Yang Ming Chiao Tung University School of Medicine, 112, Taipei, Taiwan
| | - Kuo-Jung Huang
- Division of Clinical Research, Department of Medical Research, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Chin-Tien Wang
- Institute of Clinical Medicine, National Yang Ming Chiao Tung University School of Medicine, 112, Taipei, Taiwan. .,Division of Clinical Research, Department of Medical Research, Taipei Veterans General Hospital, Taipei, Taiwan.
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17
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Lagadec F, Parissi V, Lesbats P. Targeting the Nucleosome Acidic Patch by Viral Proteins: Two Birds with One Stone? mBio 2022;:e0173321. [PMID: 35343785 DOI: 10.1128/mbio.01733-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The past decade illuminated the H2A-H2B acidic patch as a cornerstone for both nucleosome recognition and chromatin structure regulation. Higher-order folding of chromatin arrays is mediated by interactions of histone H4 tail with an adjacent nucleosome acidic patch. Dynamic chromatin folding ensures a proper regulation of nuclear functions fundamental to cellular homeostasis. Many cellular factors have been shown to act on chromatin by tethering nucleosomes via an arginine anchor binding to the acidic patch. This tethering mechanism has also been described for several viral proteins. In this minireview, we will discuss the structural basis for acidic patch engagement by viral proteins and the implications during respective viral infections. We will also discuss a model in which acidic patch occupancy by these non-self viral proteins alters the local chromatin state by preventing H4 tail-mediated higher-order chromatin folding.
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Gilmer O, Mailler E, Paillart JC, Mouhand A, Tisné C, Mak J, Smyth RP, Marquet R, Vivet-Boudou V. Structural maturation of the HIV-1 RNA 5' untranslated region by Pr55 Gag and its maturation products. RNA Biol 2022; 19:191-205. [PMID: 35067194 PMCID: PMC8786341 DOI: 10.1080/15476286.2021.2021677] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Maturation of the HIV-1 viral particles shortly after budding is required for infectivity. During this process, the Pr55Gag precursor undergoes a cascade of proteolytic cleavages, and whilst the structural rearrangements of the viral proteins are well understood, the concomitant maturation of the genomic RNA (gRNA) structure is unexplored, despite evidence that it is required for infectivity. To get insight into this process, we systematically analysed the interactions between Pr55Gag or its maturation products (NCp15, NCp9 and NCp7) and the 5ʹ gRNA region and their structural consequences, in vitro. We show that Pr55Gag and its maturation products mostly bind at different RNA sites and with different contributions of their two zinc knuckle domains. Importantly, these proteins have different transient and permanent effects on the RNA structure, the late NCp9 and NCp7 inducing dramatic structural rearrangements. Altogether, our results reveal the distinct contributions of the different Pr55Gag maturation products on the gRNA structural maturation.
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Affiliation(s)
- Orian Gilmer
- Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR 9002, IBMC, Strasbourg, France
| | - Elodie Mailler
- Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR 9002, IBMC, Strasbourg, France
| | - Jean-Christophe Paillart
- Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR 9002, IBMC, Strasbourg, France
| | - Assia Mouhand
- Expression Génétique Microbienne, UMR 8261, CNRS, Université de Paris, Institut de Biologie Physico-chimique, Paris, France
| | - Carine Tisné
- Expression Génétique Microbienne, UMR 8261, CNRS, Université de Paris, Institut de Biologie Physico-chimique, Paris, France
| | - Johnson Mak
- Institute for Glycomics, Griffith University, Gold Coast, Australia
| | - Redmond P Smyth
- Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR 9002, IBMC, Strasbourg, France
| | - Roland Marquet
- Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR 9002, IBMC, Strasbourg, France
| | - Valérie Vivet-Boudou
- Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR 9002, IBMC, Strasbourg, France
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Benner BE, Bruce JW, Kentala JR, Murray M, Becker JT, Garcia-Miranda P, Ahlquist P, Butcher SE, Sherer NM. Perturbing HIV-1 Ribosomal Frameshifting Frequency Reveals a cis Preference for Gag-Pol Incorporation into Assembling Virions. J Virol 2022; 96:e0134921. [PMID: 34643428 PMCID: PMC8754204 DOI: 10.1128/jvi.01349-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Accepted: 09/30/2021] [Indexed: 12/29/2022] Open
Abstract
HIV-1 virion production is driven by Gag and Gag-Pol (GP) proteins, with Gag forming the bulk of the capsid and driving budding, while GP binds Gag to deliver the essential virion enzymes protease, reverse transcriptase, and integrase. Virion GP levels are traditionally thought to reflect the relative abundances of GP and Gag in cells (∼1:20), dictated by the frequency of a -1 programmed ribosomal frameshifting (PRF) event occurring in gag-pol mRNAs. Here, we exploited a panel of PRF mutant viruses to show that mechanisms in addition to PRF regulate GP incorporation into virions. First, we show that GP is enriched ∼3-fold in virions relative to cells, with viral infectivity being better maintained at subphysiological levels of GP than when GP levels are too high. Second, we report that GP is more efficiently incorporated into virions when Gag and GP are synthesized in cis (i.e., from the same gag-pol mRNA) than in trans, suggesting that Gag/GP translation and assembly are spatially coupled processes. Third, we show that, surprisingly, virions exhibit a strong upper limit to trans-delivered GP incorporation; an adaptation that appears to allow the virus to temper defects to GP/Gag cleavage that may negatively impact reverse transcription. Taking these results together, we propose a "weighted Goldilocks" scenario for HIV-1 GP incorporation, wherein combined mechanisms of GP enrichment and exclusion buffer virion infectivity over a broad range of local GP concentrations. These results provide new insights into the HIV-1 virion assembly pathway relevant to the anticipated efficacy of PRF-targeted antiviral strategies. IMPORTANCE HIV-1 infectivity requires incorporation of the Gag-Pol (GP) precursor polyprotein into virions during the process of virus particle assembly. Mechanisms dictating GP incorporation into assembling virions are poorly defined, with GP levels in virions traditionally thought to solely reflect relative levels of Gag and GP expressed in cells, dictated by the frequency of a -1 programmed ribosomal frameshifting (PRF) event that occurs in gag-pol mRNAs. Herein, we provide experimental support for a "weighted Goldilocks" scenario for GP incorporation, wherein the virus exploits both random and nonrandom mechanisms to buffer infectivity over a wide range of GP expression levels. These mechanistic data are relevant to ongoing efforts to develop antiviral strategies targeting PRF frequency and/or HIV-1 virion maturation.
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Affiliation(s)
- Bayleigh E. Benner
- Department of Oncology (McArdle Laboratory for Cancer Research), Institute for Molecular Virology, and Carbone Cancer Center, University of Wisconsin—Madison, Madison, Wisconsin, USA
- UW—Madison Microbiology Doctoral Training Program, Madison, Wisconsin, USA
| | - James W. Bruce
- Department of Oncology (McArdle Laboratory for Cancer Research), Institute for Molecular Virology, and Carbone Cancer Center, University of Wisconsin—Madison, Madison, Wisconsin, USA
- John and Jeanne Rowe Center for Research in Virology, Morgridge Institute for Research, Madison, Wisconsin, USA
| | - Jacob R. Kentala
- Department of Oncology (McArdle Laboratory for Cancer Research), Institute for Molecular Virology, and Carbone Cancer Center, University of Wisconsin—Madison, Madison, Wisconsin, USA
| | - Magdalena Murray
- Department of Oncology (McArdle Laboratory for Cancer Research), Institute for Molecular Virology, and Carbone Cancer Center, University of Wisconsin—Madison, Madison, Wisconsin, USA
| | - Jordan T. Becker
- Department of Oncology (McArdle Laboratory for Cancer Research), Institute for Molecular Virology, and Carbone Cancer Center, University of Wisconsin—Madison, Madison, Wisconsin, USA
| | - Pablo Garcia-Miranda
- Department of Oncology (McArdle Laboratory for Cancer Research), Institute for Molecular Virology, and Carbone Cancer Center, University of Wisconsin—Madison, Madison, Wisconsin, USA
- Department of Biochemistry, University of Wisconsin—Madison, Madison, Wisconsin, USA
| | - Paul Ahlquist
- Department of Oncology (McArdle Laboratory for Cancer Research), Institute for Molecular Virology, and Carbone Cancer Center, University of Wisconsin—Madison, Madison, Wisconsin, USA
- John and Jeanne Rowe Center for Research in Virology, Morgridge Institute for Research, Madison, Wisconsin, USA
| | - Samuel E. Butcher
- Department of Biochemistry, University of Wisconsin—Madison, Madison, Wisconsin, USA
| | - Nathan M. Sherer
- Department of Oncology (McArdle Laboratory for Cancer Research), Institute for Molecular Virology, and Carbone Cancer Center, University of Wisconsin—Madison, Madison, Wisconsin, USA
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Durand S, Seigneuret F, Burlaud-Gaillard J, Lemoine R, Tassi MF, Moreau A, Mougel M, Roingeard P, Tauber C, de Rocquigny H. Quantitative analysis of the formation of nucleoprotein complexes between HIV-1 Gag protein and genomic RNA using transmission electron microscopy. J Biol Chem 2022; 298:101500. [PMID: 34929171 PMCID: PMC8760521 DOI: 10.1016/j.jbc.2021.101500] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Accepted: 12/05/2021] [Indexed: 01/06/2023] Open
Abstract
In HIV, the polyprotein precursor Gag orchestrates the formation of the viral capsid. In the current view of this viral assembly, Gag forms low-order oligomers that bind to the viral genomic RNA triggering the formation of high-ordered ribonucleoprotein complexes. However, this assembly model was established using biochemical or imaging methods that do not describe the cellular location hosting Gag-gRNA complex nor distinguish gRNA packaging in single particles. Here, we studied the intracellular localization of these complexes by electron microscopy and monitored the distances between the two partners by morphometric analysis of gold beads specifically labeling Gag and gRNA. We found that formation of these viral clusters occurred shortly after the nuclear export of the gRNA. During their transport to the plasma membrane, the distance between Gag and gRNA decreases together with an increase of gRNA packaging. Point mutations in the zinc finger patterns of the nucleocapsid domain of Gag caused an increase in the distance between Gag and gRNA as well as a sharp decrease of gRNA packaged into virions. Finally, we show that removal of stem loop 1 of the 5'-untranslated region does not interfere with gRNA packaging, whereas combined with the removal of stem loop 3 is sufficient to decrease but not abolish Gag-gRNA cluster formation and gRNA packaging. In conclusion, this morphometric analysis of Gag-gRNA cluster formation sheds new light on HIV-1 assembly that can be used to describe at nanoscale resolution other viral assembly steps involving RNA or protein-protein interactions.
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Affiliation(s)
- Stéphanie Durand
- Morphogenesis and Antigenicity of HIV and Hepatitis Viruses, Inserm - U1259 MAVIVH, Bretonneau Hospital, Tours Cedex 1, France
| | - Florian Seigneuret
- Morphogenesis and Antigenicity of HIV and Hepatitis Viruses, Inserm - U1259 MAVIVH, Bretonneau Hospital, Tours Cedex 1, France
| | - Julien Burlaud-Gaillard
- Microscopy IBiSA Platform, PPF ASB, University of Tours and CHRU of Tours, Tours Cedex 1, France
| | - Roxane Lemoine
- B Cell Ressources Platform, EA4245 "Transplantation, Immunology and Inflammation", University of Tours, Tours Cedex 1, France
| | - Marc-Florent Tassi
- Morphogenesis and Antigenicity of HIV and Hepatitis Viruses, Inserm - U1259 MAVIVH, Bretonneau Hospital, Tours Cedex 1, France
| | - Alain Moreau
- Morphogenesis and Antigenicity of HIV and Hepatitis Viruses, Inserm - U1259 MAVIVH, Bretonneau Hospital, Tours Cedex 1, France
| | - Marylène Mougel
- Équipe R2D2 Retroviral RNA Dynamics and Delivery, IRIM, CNRS UMR9004, University of Montpellier, Montpellier, France
| | - Philippe Roingeard
- Morphogenesis and Antigenicity of HIV and Hepatitis Viruses, Inserm - U1259 MAVIVH, Bretonneau Hospital, Tours Cedex 1, France; Microscopy IBiSA Platform, PPF ASB, University of Tours and CHRU of Tours, Tours Cedex 1, France
| | - Clovis Tauber
- UMR U1253 iBrain, Inserm, University of Tours, Tours Cedex 1, France
| | - Hugues de Rocquigny
- Morphogenesis and Antigenicity of HIV and Hepatitis Viruses, Inserm - U1259 MAVIVH, Bretonneau Hospital, Tours Cedex 1, France.
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21
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Wang L, Sandmeyer A, Hübner W, Li H, Huser T, Chen BK. A Replication-Competent HIV Clone Carrying GFP-Env Reveals Rapid Env Recycling at the HIV-1 T Cell Virological Synapse. Viruses 2021; 14:v14010038. [PMID: 35062242 PMCID: PMC8781834 DOI: 10.3390/v14010038] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 10/08/2021] [Accepted: 12/17/2021] [Indexed: 12/24/2022] Open
Abstract
HIV-1 infection is enhanced by cell-cell adhesions between infected and uninfected T cells called virological synapses (VS). VS are initiated by the interactions of cell-surface HIV-1 envelope glycoprotein (Env) and CD4 on target cells and act as sites of viral assembly and viral transfer between cells. To study the process that recruits and retains HIV-1 Env at the VS, a replication-competent HIV-1 clone carrying an Env-sfGFP fusion protein was designed to enable live tracking of Env within infected cells. Combined use of surface pulse-labeling of Env and fluorescence recovery after photobleaching (FRAP) studies, enabled the visualization of the targeted accumulation and sustained recycling of Env between endocytic compartments (EC) and the VS. We observed dynamic exchange of Env at the VS, while the viral structural protein, Gag, was largely immobile at the VS. The disparate exchange rates of Gag and Env at the synapse support that the trafficking and/or retention of a majority of Env towards the VS is not maintained by entrapment by a Gag lattice or immobilization by binding to CD4 on the target cell. A FRAP study of an Env endocytosis mutant showed that recycling is not required for accumulation at the VS, but is required for the rapid exchange of Env at the VS. We conclude that the mechanism of Env accumulation at the VS and incorporation into nascent particles involves continuous internalization and targeted secretion rather than irreversible interactions with the budding virus, but that this recycling is largely dispensable for VS formation and viral transfer across the VS.
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Affiliation(s)
- Lili Wang
- Department of Medicine, Division of Infectious Disease, Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; (L.W.); (H.L.)
| | - Alice Sandmeyer
- Biomolecular Photonics, Department of Physics, University of Bielefeld, 33615 Bielefeld, Germany; (A.S.); (W.H.); (T.H.)
| | - Wolfgang Hübner
- Biomolecular Photonics, Department of Physics, University of Bielefeld, 33615 Bielefeld, Germany; (A.S.); (W.H.); (T.H.)
| | - Hongru Li
- Department of Medicine, Division of Infectious Disease, Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; (L.W.); (H.L.)
| | - Thomas Huser
- Biomolecular Photonics, Department of Physics, University of Bielefeld, 33615 Bielefeld, Germany; (A.S.); (W.H.); (T.H.)
| | - Benjamin K. Chen
- Department of Medicine, Division of Infectious Disease, Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; (L.W.); (H.L.)
- Correspondence:
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22
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Duchon A, Santos S, Chen J, Brown M, Nikolaitchik OA, Tai S, Chao JA, Freed EO, Pathak VK, Hu WS. Plasma Membrane Anchoring and Gag:Gag Multimerization on Viral RNA Are Critical Properties of HIV-1 Gag Required To Mediate Efficient Genome Packaging. mBio 2021; 12:e0325421. [PMID: 34872357 DOI: 10.1128/mbio.03254-21] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human immunodeficiency virus type 1 (HIV-1) Gag selects and packages the HIV RNA genome during virus assembly. However, HIV-1 RNA constitutes only a small fraction of the cellular RNA. Although Gag exhibits a slight preference to viral RNA, most of the cytoplasmic Gag proteins are associated with cellular RNAs. Thus, it is not understood how HIV-1 achieves highly efficient genome packaging. We hypothesize that besides RNA binding, other properties of Gag are important for genome packaging. Many Gag mutants have assembly defects that preclude analysis of their effects on genome packaging. To bypass this challenge, we established complementation systems that separate the particle-assembling and RNA-binding functions of Gag: we used a set of Gag proteins to drive particle assembly and an RNA-binding Gag to package HIV-1 RNA. We have developed two types of RNA-binding Gag in which packaging is mediated by the authentic nucleocapsid (NC) domain or by a nonviral RNA-binding domain. We found that in both cases, mutations that affect the multimerization or plasma membrane anchoring properties of Gag reduce or abolish RNA packaging. These mutant Gag can coassemble into particles but cannot package the RNA genome efficiently. Our findings indicate that HIV-1 RNA packaging occurs at the plasma membrane and RNA-binding Gag needs to multimerize on RNA to encapsidate the viral genome.
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23
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D’Souza AR, Jayaraman D, Long Z, Zeng J, Prestwood LJ, Chan C, Kappei D, Lever AML, Kenyon JC. HIV-1 Packaging Visualised by In-Gel SHAPE. Viruses 2021; 13:v13122389. [PMID: 34960658 PMCID: PMC8707378 DOI: 10.3390/v13122389] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 11/21/2021] [Accepted: 11/23/2021] [Indexed: 11/16/2022] Open
Abstract
HIV-1 packages two copies of its gRNA into virions via an interaction with the viral structural protein Gag. Both copies and their native RNA structure are essential for virion infectivity. The precise stepwise nature of the packaging process has not been resolved. This is largely due to a prior lack of structural techniques that follow RNA structural changes within an RNA-protein complex. Here, we apply the in-gel SHAPE (selective 2'OH acylation analysed by primer extension) technique to study the initiation of HIV-1 packaging, examining the interaction between the packaging signal RNA and the Gag polyprotein, and compare it with that of the NC domain of Gag alone. Our results imply interactions between Gag and monomeric packaging signal RNA in switching the RNA conformation into a dimerisation-competent structure, and show that the Gag-dimer complex then continues to stabilise. These data provide a novel insight into how HIV-1 regulates the translation and packaging of its genome.
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Affiliation(s)
- Aaron R. D’Souza
- Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119228, Singapore; (A.R.D.); (D.J.)
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117599, Singapore; (C.C.); (D.K.)
| | - Dhivya Jayaraman
- Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119228, Singapore; (A.R.D.); (D.J.)
| | - Ziqi Long
- Department of Medicine, University of Cambridge, Level 5 Addenbrookes Hospital, Cambridge CB2 0QQ, UK; (Z.L.); (J.Z.); (L.J.P.)
| | - Jingwei Zeng
- Department of Medicine, University of Cambridge, Level 5 Addenbrookes Hospital, Cambridge CB2 0QQ, UK; (Z.L.); (J.Z.); (L.J.P.)
| | - Liam J. Prestwood
- Department of Medicine, University of Cambridge, Level 5 Addenbrookes Hospital, Cambridge CB2 0QQ, UK; (Z.L.); (J.Z.); (L.J.P.)
| | - Charlene Chan
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117599, Singapore; (C.C.); (D.K.)
| | - Dennis Kappei
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117599, Singapore; (C.C.); (D.K.)
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117596, Singapore
- NUS Center for Cancer Research, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Andrew M. L. Lever
- Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119228, Singapore; (A.R.D.); (D.J.)
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117599, Singapore; (C.C.); (D.K.)
- Department of Medicine, University of Cambridge, Level 5 Addenbrookes Hospital, Cambridge CB2 0QQ, UK; (Z.L.); (J.Z.); (L.J.P.)
- Correspondence: (A.M.L.L.); (J.C.K.); Tel.: +44-(0)1-2237-47308 (J.C.K.)
| | - Julia C. Kenyon
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117599, Singapore; (C.C.); (D.K.)
- Department of Medicine, University of Cambridge, Level 5 Addenbrookes Hospital, Cambridge CB2 0QQ, UK; (Z.L.); (J.Z.); (L.J.P.)
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117545, Singapore
- Homerton College, University of Cambridge, Cambridge CB2 8PH, UK
- Correspondence: (A.M.L.L.); (J.C.K.); Tel.: +44-(0)1-2237-47308 (J.C.K.)
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24
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Long M, Toesca J, Guillon C. Review and Perspectives on the Structure-Function Relationships of the Gag Subunits of Feline Immunodeficiency Virus. Pathogens 2021; 10:pathogens10111502. [PMID: 34832657 PMCID: PMC8621984 DOI: 10.3390/pathogens10111502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 11/16/2021] [Accepted: 11/16/2021] [Indexed: 11/16/2022] Open
Abstract
The Gag polyprotein is implied in the budding as well as the establishment of the supramolecular architecture of infectious retroviral particles. It is also involved in the early phases of the replication of retroviruses by protecting and transporting the viral genome towards the nucleus of the infected cell until its integration in the host genome. Therefore, understanding the structure-function relationships of the Gag subunits is crucial as each of them can represent a therapeutic target. Though the field has been explored for some time in the area of Human Immunodeficiency Virus (HIV), it is only in the last decade that structural data on Feline Immunodeficiency Virus (FIV) Gag subunits have emerged. As FIV is an important veterinary issue, both in domestic cats and endangered feline species, such data are of prime importance for the development of anti-FIV molecules targeting Gag. This review will focus on the recent advances and perspectives on the structure-function relationships of each subunit of the FIV Gag polyprotein.
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Affiliation(s)
- Mathieu Long
- Retroviruses and Structural Biochemistry, Molecular Microbiology and Structural Biochemistry, CNRS, Univ Lyon, UMR5086, 69007 Lyon, France; (M.L.); (J.T.)
- Center for Molecular Protein Science, Department of Chemistry, Lund University, Lund, 221 00 Scania, Sweden
| | - Johan Toesca
- Retroviruses and Structural Biochemistry, Molecular Microbiology and Structural Biochemistry, CNRS, Univ Lyon, UMR5086, 69007 Lyon, France; (M.L.); (J.T.)
- Enveloped Viruses, Vectors and Immunotherapy, CIRI-Centre International de Recherche en Infectiologie, Univ Lyon, Université Claude Bernard Lyon 1, UMR5308, ENS Lyon, 69007 Lyon, France
| | - Christophe Guillon
- Retroviruses and Structural Biochemistry, Molecular Microbiology and Structural Biochemistry, CNRS, Univ Lyon, UMR5086, 69007 Lyon, France; (M.L.); (J.T.)
- Correspondence:
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25
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Castro-Gonzalez S, Chen Y, Benjamin J, Shi Y, Serra-Moreno R. Residues T 48 and A 49 in HIV-1 NL4-3 Nef are responsible for the counteraction of autophagy initiation, which prevents the ubiquitin-dependent degradation of Gag through autophagosomes. Retrovirology 2021; 18:33. [PMID: 34711257 PMCID: PMC8555152 DOI: 10.1186/s12977-021-00576-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Accepted: 10/05/2021] [Indexed: 11/21/2022] Open
Abstract
Background Autophagy plays an important role as a cellular defense mechanism against intracellular pathogens, like viruses. Specifically, autophagy orchestrates the recruitment of specialized cargo, including viral components needed for replication, for lysosomal degradation. In addition to this primary role, the cleavage of viral structures facilitates their association with pattern recognition receptors and MHC-I/II complexes, which assists in the modulation of innate and adaptive immune responses against these pathogens. Importantly, whereas autophagy restricts the replicative capacity of human immunodeficiency virus type 1 (HIV-1), this virus has evolved the gene nef to circumvent this process through the inhibition of early and late stages of the autophagy cascade. Despite recent advances, many details of the mutual antagonism between HIV-1 and autophagy still remain unknown. Here, we uncover the genetic determinants that drive the autophagy-mediated restriction of HIV-1 as well as the counteraction imposed by Nef. Additionally, we also examine the implications of autophagy antagonism in HIV-1 infectivity. Results We found that sustained activation of autophagy potently inhibits HIV-1 replication through the degradation of HIV-1 Gag, and that this effect is more prominent for nef-deficient viruses. Gag re-localizes to autophagosomes where it interacts with the autophagosome markers LC3 and SQSTM1. Importantly, autophagy-mediated recognition and recruitment of Gag requires the myristoylation and ubiquitination of this virus protein, two post-translational modifications that are essential for Gag’s central role in virion assembly and budding. We also identified residues T48 and A49 in HIV-1 NL4-3 Nef as responsible for impairing the early stages of autophagy. Finally, a survey of pandemic HIV-1 transmitted/founder viruses revealed that these isolates are highly resistant to autophagy restriction. Conclusions This study provides evidence that autophagy antagonism is important for virus replication and suggests that the ability of Nef to counteract autophagy may have played an important role in mucosal transmission. Hence, disabling Nef in combination with the pharmacological manipulation of autophagy represents a promising strategy to prevent HIV spread. Supplementary Information The online version contains supplementary material available at 10.1186/s12977-021-00576-y.
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Affiliation(s)
| | - Yuexuan Chen
- Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY, USA
| | - Jared Benjamin
- Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY, USA
| | - Yuhang Shi
- Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY, USA
| | - Ruth Serra-Moreno
- Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY, USA.
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26
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Obr M, Schur FKM, Dick RA. A Structural Perspective of the Role of IP6 in Immature and Mature Retroviral Assembly. Viruses 2021; 13:1853. [PMID: 34578434 DOI: 10.3390/v13091853] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 09/10/2021] [Accepted: 09/12/2021] [Indexed: 11/17/2022] Open
Abstract
The small cellular molecule inositol hexakisphosphate (IP6) has been known for ~20 years to promote the in vitro assembly of HIV-1 into immature virus-like particles. However, the molecular details underlying this effect have been determined only recently, with the identification of the IP6 binding site in the immature Gag lattice. IP6 also promotes formation of the mature capsid protein (CA) lattice via a second IP6 binding site, and enhances core stability, creating a favorable environment for reverse transcription. IP6 also enhances assembly of other retroviruses, from both the Lentivirus and the Alpharetrovirus genera. These findings suggest that IP6 may have a conserved function throughout the family Retroviridae. Here, we discuss the different steps in the viral life cycle that are influenced by IP6, and describe in detail how IP6 interacts with the immature and mature lattices of different retroviruses.
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27
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Zhang J. Interplay between Host tRNAs and HIV-1: A Structural Perspective. Viruses 2021; 13:1819. [PMID: 34578400 DOI: 10.3390/v13091819] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 09/06/2021] [Accepted: 09/09/2021] [Indexed: 12/23/2022] Open
Abstract
The cellular metabolism of host tRNAs and life cycle of HIV-1 cross paths at several key virus-host interfaces. Emerging data suggest a multi-faceted interplay between host tRNAs and HIV-1 that plays essential roles, both structural and regulatory, in viral genome replication, genome packaging, and virion biogenesis. HIV-1 not only hijacks host tRNAs and transforms them into obligatory reverse transcription primers but further commandeers tRNAs to regulate the localization of its major structural protein, Gag, via a specific interface. This review highlights recent advances in understanding tRNA-HIV-1 interactions, primarily from a structural perspective, which start to elucidate their underlying molecular mechanisms, intrinsic specificities, and biological significances. Such understanding may provide new avenues toward developing HIV/AIDS treatments and therapeutics including small molecules and RNA biologics that target these host-virus interfaces.
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Bou-Nader C, Muecksch F, Brown JB, Gordon JM, York A, Peng C, Ghirlando R, Summers MF, Bieniasz PD, Zhang J. HIV-1 matrix-tRNA complex structure reveals basis for host control of Gag localization. Cell Host Microbe 2021; 29:1421-1436.e7. [PMID: 34384537 PMCID: PMC8650744 DOI: 10.1016/j.chom.2021.07.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 05/24/2021] [Accepted: 07/19/2021] [Indexed: 10/20/2022]
Abstract
The HIV-1 virion structural polyprotein, Gag, is directed to particle assembly sites at the plasma membrane by its N-terminal matrix (MA) domain. MA also binds to host tRNAs. To understand the molecular basis of MA-tRNA interaction and its potential function, we present a co-crystal structure of HIV-1 MA-tRNALys3 complex. The structure reveals a specialized group of MA basic and aromatic residues preconfigured to recognize the distinctive structure of the tRNA elbow. Mutational, cross-linking, fluorescence, and NMR analyses show that the crystallographically defined interface drives MA-tRNA binding in solution and living cells. The structure indicates that MA is unlikely to bind tRNA and membrane simultaneously. Accordingly, single-amino-acid substitutions that abolish MA-tRNA binding caused striking redistribution of Gag to the plasma membrane and reduced HIV-1 replication. Thus, HIV-1 exploits host tRNAs to occlude a membrane localization signal and control the subcellular distribution of its major structural protein.
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Affiliation(s)
- Charles Bou-Nader
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA
| | - Frauke Muecksch
- Laboratory of Retrovirology, The Rockefeller University, New York, NY 10065, USA
| | - Janae B Brown
- Department of Chemistry and Biochemistry, University of Maryland, Baltimore County, Baltimore, MD 21250, USA
| | - Jackson M Gordon
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA
| | - Ashley York
- Laboratory of Retrovirology, The Rockefeller University, New York, NY 10065, USA
| | - Chen Peng
- Laboratory of Retrovirology, The Rockefeller University, New York, NY 10065, USA
| | - Rodolfo Ghirlando
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA
| | - Michael F Summers
- Department of Chemistry and Biochemistry, University of Maryland, Baltimore County, Baltimore, MD 21250, USA; Howard Hughes Medical Institute, University of Maryland, Baltimore County, Baltimore, MD 21250, USA
| | - Paul D Bieniasz
- Laboratory of Retrovirology, The Rockefeller University, New York, NY 10065, USA; Howard Hughes Medical Institute, The Rockefeller University, New York, NY 10065, USA.
| | - Jinwei Zhang
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA.
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29
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Gumna J, Andrzejewska-Romanowska A, Garfinkel DJ, Pachulska-Wieczorek K. RNA Binding Properties of the Ty1 LTR-Retrotransposon Gag Protein. Int J Mol Sci 2021; 22:ijms22169103. [PMID: 34445809 PMCID: PMC8396678 DOI: 10.3390/ijms22169103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Revised: 08/21/2021] [Accepted: 08/22/2021] [Indexed: 11/16/2022] Open
Abstract
A universal feature of retroelement propagation is the formation of distinct nucleoprotein complexes mediated by the Gag capsid protein. The Ty1 retrotransposon Gag protein from Saccharomyces cerevisiae lacks sequence homology with retroviral Gag, but is functionally related. In addition to capsid assembly functions, Ty1 Gag promotes Ty1 RNA dimerization and cyclization and initiation of reverse transcription. Direct interactions between Gag and retrotransposon genomic RNA (gRNA) are needed for Ty1 replication, and mutations in the RNA-binding domain disrupt nucleation of retrosomes and assembly of functional virus-like particles (VLPs). Unlike retroviral Gag, the specificity of Ty1 Gag-RNA interactions remain poorly understood. Here we use microscale thermophoresis (MST) and electrophoretic mobility shift assays (EMSA) to analyze interactions of immature and mature Ty1 Gag with RNAs. The salt-dependent experiments showed that Ty1 Gag binds with high and similar affinity to different RNAs. However, we observed a preferential interaction between Ty1 Gag and Ty1 RNA containing a packaging signal (Psi) in RNA competition analyses. We also uncover a relationship between Ty1 RNA structure and Gag binding involving the pseudoknot present on Ty1 gRNA. In all likelihood, the differences in Gag binding affinity detected in vitro only partially explain selective Ty1 RNA packaging into VLPs in vivo.
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Affiliation(s)
- Julita Gumna
- Department of Structure and Function of Retrotransposons, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland; (J.G.); (A.A.-R.)
| | - Angelika Andrzejewska-Romanowska
- Department of Structure and Function of Retrotransposons, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland; (J.G.); (A.A.-R.)
| | - David J. Garfinkel
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA;
| | - Katarzyna Pachulska-Wieczorek
- Department of Structure and Function of Retrotransposons, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland; (J.G.); (A.A.-R.)
- Correspondence: ; Tel.: +48-61-852-85-03; Fax: +48-61-852-05-32
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30
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Wanaguru M, Bishop KN. HIV-1 Gag Recruits Oligomeric Vpr via Two Binding Sites in p6, but Both Mature p6 and Vpr Are Rapidly Lost upon Target Cell Entry. J Virol 2021; 95:e0055421. [PMID: 34106747 DOI: 10.1128/JVI.00554-21] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The p12 region of murine leukemia virus (MLV) Gag and the p6 region of HIV-1 Gag contain late domains required for virus budding. Additionally, the accessory protein Vpr is recruited into HIV particles via p6. Mature p12 is essential for early viral replication events, but the role of mature p6 in early replication is unknown. Using a proviral vector in which the gag and pol reading frames are uncoupled, we have performed the first alanine-scanning mutagenesis screens across p6 to probe its importance for early HIV-1 replication and to further understand its interaction with Vpr. The infectivity of our mutants suggests that, unlike p12, p6 is not important for early viral replication. Consistent with this, we observed that p6 is rapidly lost upon target cell entry in time course immunoblot experiments. By analyzing Vpr incorporation into p6 mutant virions, we identified that the 15-FRFG-18 and 41-LXXLF-45 motifs previously identified as putative Vpr-binding sites are important for Vpr recruitment but that the 34-ELY-36 motif also suggested to be a Vpr-binding site is dispensable. Additionally, disrupting Vpr oligomerization together with removing either binding motif in p6 reduced Vpr incorporation ∼25- to 50-fold more than inhibiting Vpr oligomerization alone and ∼10- to 25-fold more than deleting each p6 motif alone, implying that multivalency/avidity is important for the interaction. Interestingly, using immunoblotting and immunofluorescence, we observed that most Vpr is lost concomitantly with p6 during infection but that a small fraction remains associated with the viral capsid for several hours. This has implications for the function of Vpr in early replication. IMPORTANCE The p12 protein of MLV and the p6 protein of HIV-1 are both supplementary Gag cleavage products that carry proline-rich motifs that facilitate virus budding. Importantly, p12 has also been found to be essential for early viral replication events. However, while Vpr, the only accessory protein packaged into HIV-1 virions, is recruited via the p6 region of Gag, the function of both mature p6 and Vpr in early replication is unclear. Here, we have systematically mutated the p6 region of Gag and have studied the effects on HIV infectivity and Vpr packaging. We have also investigated what happens to p6 and Vpr during early infection. We show that, unlike p12, mature p6 is not required for early replication and that most of the mature p6 and the Vpr that it recruits are lost rapidly upon target cell entry. This has implications for the role of Vpr in target cells.
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Moysi E, Darko S, Gea-Mallorquí E, Petrovas C, Almeida JR, Wolinsky D, Peng Y, Jaye A, Stewart-Jones G, Douek DC, Koup RA, Dong T, Rowland-Jones S. Clonotypic architecture of a Gag-specific CD8+ T-cell response in chronic human HIV-2 infection. Eur J Immunol 2021; 51:2485-2500. [PMID: 34369597 DOI: 10.1002/eji.202048931] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2020] [Revised: 06/07/2021] [Accepted: 08/05/2021] [Indexed: 11/08/2022]
Abstract
The dynamics of T-cell receptor (TCR) selection in chronic HIV-1 infection, and its association with clinical outcome, is well documented for an array of MHC-peptide complexes and disease stages. However, the factors that may contribute to the selection and expansion of CD8+ T-cells in chronic HIV-2 infection, especially at clonal level remain unclear. To address this question, we undertook a detailed molecular characterization of the clonotypic architecture of an HLA-B*3501 restricted Gag -specific CD8+ T-cell response in donors chronically infected with HIV-2 using a combination of flow cytometry, tetramer-specific CD8+ TCR clonotyping and in vitro assays. We show that the response to the NY9 epitope is hierarchical and narrow in terms of T-cell receptor alpha (TCRA) and beta (TCRB) gene usage yet clonotypically diverse. Furthermore, clonotypic dominance in shared origin cytotoxic T lymphocyte (CTL) clones was associated with a greater magnitude of cytokine production and antigen sensitivity at limiting antigen dilution as well as enhanced cross-reactivity for known HIV-2 variants. Hence, our data suggest that effector mobilization and expansion in human chronic HIV-2 infection may be linked to the qualitative features of specific CD8+ T-cell clonotypes, which could have implications for viral control and disease outcome. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Eirini Moysi
- Tissue Analysis Core, Vaccine Research Centre, Bethesda, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, MD, 20892, USA
| | - Samuel Darko
- Human Immunology Section, Vaccine Research Center, NIAID, NIH, Bethesda, MD, 20892, USA
| | - Ester Gea-Mallorquí
- Viral Immunology Unit, Nuffield Department of Medicine, Headington, Oxford, OX3 7FZ, United Kingdom
| | - Constantinos Petrovas
- Tissue Analysis Core, Vaccine Research Centre, Bethesda, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, MD, 20892, USA
| | - Jorge R Almeida
- Human Immunology Section, Vaccine Research Center, NIAID, NIH, Bethesda, MD, 20892, USA
| | - David Wolinsky
- Human Immunology Section, Vaccine Research Center, NIAID, NIH, Bethesda, MD, 20892, USA
| | - Yanchun Peng
- MRC Human Immunology Unit, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Headington, Oxford, OX3 9DS, United Kingdom
| | - Assan Jaye
- MRC Laboratories, The Gambia, PO Box 273, West Africa
| | - Guillaume Stewart-Jones
- Structural Biology Section, Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Daniel C Douek
- Human Immunology Section, Vaccine Research Center, NIAID, NIH, Bethesda, MD, 20892, USA
| | - Richard A Koup
- Immunology Laboratory, Vaccine Research Center, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, MD, 20892, USA
| | - Tao Dong
- MRC Human Immunology Unit, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Headington, Oxford, OX3 9DS, United Kingdom
| | - Sarah Rowland-Jones
- Viral Immunology Unit, Nuffield Department of Medicine, Headington, Oxford, OX3 7FZ, United Kingdom
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Alfadhli A, Romanaggi C, Barklis RL, Merutka I, Bates TA, Tafesse FG, Barklis E. Capsid-specific nanobody effects on HIV-1 assembly and infectivity. Virology 2021; 562:19-28. [PMID: 34246112 DOI: 10.1016/j.virol.2021.07.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 07/01/2021] [Accepted: 07/01/2021] [Indexed: 11/15/2022]
Abstract
The capsid (CA) domain of the HIV-1 precursor Gag (PrGag) protein plays multiple roles in HIV-1 replication, and is central to the assembly of immature virions, and mature virus cores. CA proteins themselves are composed of N-terminal domains (NTDs) and C-terminal domains (CTDs). We have investigated the interactions of CA with anti-CA nanobodies, which derive from the antigen recognition regions of camelid heavy chain-only antibodies. The one CA NTD-specific and two CTD-specific nanobodies we analyzed proved sensitive and specific HIV-1 CA detection reagents in immunoassays. When co-expressed with HIV-1 Gag proteins in cells, the NTD-specific nanobody was efficiently assembled into virions and did not perturb virus assembly. In contrast, the two CTD-specific nanobodies reduced PrGag processing, virus release and HIV-1 infectivity. Our results demonstrate the feasibility of Gag-targeted nanobody inhibition of HIV-1.
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Affiliation(s)
- Ayna Alfadhli
- Department of Molecular Microbiology and Immunology, Oregon Health and Sciences University, 3181 SW Sam Jackson Park Road, Portland, OR, 97239-3098, USA
| | - CeAnn Romanaggi
- Department of Molecular Microbiology and Immunology, Oregon Health and Sciences University, 3181 SW Sam Jackson Park Road, Portland, OR, 97239-3098, USA
| | - Robin Lid Barklis
- Department of Molecular Microbiology and Immunology, Oregon Health and Sciences University, 3181 SW Sam Jackson Park Road, Portland, OR, 97239-3098, USA
| | - Ilaria Merutka
- Department of Molecular Microbiology and Immunology, Oregon Health and Sciences University, 3181 SW Sam Jackson Park Road, Portland, OR, 97239-3098, USA
| | - Timothy A Bates
- Department of Molecular Microbiology and Immunology, Oregon Health and Sciences University, 3181 SW Sam Jackson Park Road, Portland, OR, 97239-3098, USA
| | - Fikadu G Tafesse
- Department of Molecular Microbiology and Immunology, Oregon Health and Sciences University, 3181 SW Sam Jackson Park Road, Portland, OR, 97239-3098, USA.
| | - Eric Barklis
- Department of Molecular Microbiology and Immunology, Oregon Health and Sciences University, 3181 SW Sam Jackson Park Road, Portland, OR, 97239-3098, USA.
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Yang H, Llano A, Cedeño S, von Delft A, Corcuera A, Gillespie GM, Knox A, Leneghan DB, Frater J, Stöhr W, Fidler S, Mothe B, Mak J, Brander C, Ternette N, Dorrell L. Incoming HIV virion-derived Gag Spacer Peptide 2 (p1) is a target of effective CD8 + T cell antiviral responses. Cell Rep 2021; 35:109103. [PMID: 33979627 DOI: 10.1016/j.celrep.2021.109103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 02/20/2021] [Accepted: 04/16/2021] [Indexed: 10/21/2022] Open
Abstract
Persistence of HIV through integration into host DNA in CD4+ T cells presents a major barrier to virus eradication. Viral integration may be curtailed when CD8+ T cells are triggered to kill infected CD4+ T cells through recognition of histocompatibility leukocyte antigen (HLA) class I-bound peptides derived from incoming virions. However, this has been reported only in individuals with "beneficial" HLA alleles that are associated with superior HIV control. Through interrogation of the pre-integration immunopeptidome, we obtain proof of early presentation of a virion-derived HLA-A∗02:01-restricted epitope, FLGKIWPSH (FH9), located in Gag Spacer Peptide 2 (SP2). FH9-specific CD8+ T cell responses are detectable in individuals with primary HIV infection and eliminate HIV-infected CD4+ T cells prior to virus production in vitro. Our data show that non-beneficial HLA class I alleles can elicit an effective antiviral response through early presentation of HIV virion-derived epitopes and also demonstrate the importance of SP2 as an immune target.
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Affiliation(s)
- Hongbing Yang
- Nuffield Department of Medicine, University of Oxford, Oxford OX3 7FZ, UK; National Institute for Health Research Oxford Biomedical Research Centre, University of Oxford, Oxford OX4 2PG, UK; Research In Viral Eradication of Reservoirs (RIVER) trial study group.
| | - Anuska Llano
- Irsicaixa AIDS Research Institute-HIVACAT, Hospital Universitari Germans Trias i Pujol, 08916 Badalona, Spain
| | - Samandhy Cedeño
- Irsicaixa AIDS Research Institute-HIVACAT, Hospital Universitari Germans Trias i Pujol, 08916 Badalona, Spain
| | - Annette von Delft
- National Institute for Health Research Oxford Biomedical Research Centre, University of Oxford, Oxford OX4 2PG, UK; Centre for Medicines Discovery, University of Oxford, Oxford, UK
| | - Angelica Corcuera
- Nuffield Department of Medicine, University of Oxford, Oxford OX3 7FZ, UK
| | | | - Andrew Knox
- Immunocore Ltd, Milton, Abingdon OX14 4RY, UK
| | | | - John Frater
- Nuffield Department of Medicine, University of Oxford, Oxford OX3 7FZ, UK; National Institute for Health Research Oxford Biomedical Research Centre, University of Oxford, Oxford OX4 2PG, UK; Research In Viral Eradication of Reservoirs (RIVER) trial study group
| | - Wolfgang Stöhr
- Medical Research Council Clinical Trials Unit, University College London, London WC1V 6LJ, UK; Research In Viral Eradication of Reservoirs (RIVER) trial study group
| | - Sarah Fidler
- Department of Infectious Disease, Imperial College London, National Institute for Health Research Imperial Biomedical Research Centre, London W2 1NY, UK; Research In Viral Eradication of Reservoirs (RIVER) trial study group
| | - Beatriz Mothe
- Irsicaixa AIDS Research Institute-HIVACAT, Hospital Universitari Germans Trias i Pujol, 08916 Badalona, Spain; Faculty of Medicine, Universitat de Vic-Central de Catalunya (UVic-UCC), 08500 Vic, Spain; Fundació Lluita contra la Sida, Infectious Disease Department, Hospital Universitari Germans Trias i Pujol, 08916 Badalona, Spain
| | - Johnson Mak
- Institute for Glycomics, Griffith University Gold Coast, Southport QLD 4215, Australia
| | - Christian Brander
- Irsicaixa AIDS Research Institute-HIVACAT, Hospital Universitari Germans Trias i Pujol, 08916 Badalona, Spain; Faculty of Medicine, Universitat de Vic-Central de Catalunya (UVic-UCC), 08500 Vic, Spain; Institució Catalana de Recerca I Estudis Avançats (ICREA), 08010 Barcelona, Spain
| | - Nicola Ternette
- Nuffield Department of Medicine, University of Oxford, Oxford OX3 7FZ, UK
| | - Lucy Dorrell
- Nuffield Department of Medicine, University of Oxford, Oxford OX3 7FZ, UK; National Institute for Health Research Oxford Biomedical Research Centre, University of Oxford, Oxford OX4 2PG, UK; Immunocore Ltd, Milton, Abingdon OX14 4RY, UK; Research In Viral Eradication of Reservoirs (RIVER) trial study group.
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Lavado-García J, Jorge I, Boix-Besora A, Vázquez J, Gòdia F, Cervera L. Characterization of HIV-1 virus-like particles and determination of Gag stoichiometry for different production platforms. Biotechnol Bioeng 2021; 118:2660-2675. [PMID: 33844274 DOI: 10.1002/bit.27786] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 04/06/2021] [Accepted: 04/08/2021] [Indexed: 11/10/2022]
Abstract
The importance of developing new vaccine technologies towards versatile platforms that can cope with global virus outbreaks has been evidenced with the most recent severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. Virus-like particles (VLPs) are a highly immunogenic, safe, and robust approach that can be used to base several vaccine candidates on. Particularly, HIV-1 Gag VLPs is a flexible system comprising a Gag core surrounded by a lipid bilayer that can be modified to present diverse types of membrane proteins or antigens against several diseases, like influenza, dengue, West Nile virus, or human papillomavirus, where it has been proven successful. The size distribution and structural characteristics of produced VLPs vary depending on the cell line used to produce them. In this study, we established an analytical method of characterization for the Gag protein core and clarified the current variability of Gag stoichiometry in HIV-1 VLPs depending on the cell-based production platform, directly determining the number of Gag molecules per VLP in each case. Three Gag peptides have been validated to quantify the number of monomers using parallel reaction monitoring, an accurate and fast, mass-spectrometry-based method that can be used to assess the quality of the produced Gag VLPs regardless of the cell line used. An average of 3617 ± 17 monomers per VLP was obtained for HEK293, substantially varying between platforms, including mammalian and insect cells. This offers a key advantage in quantification and quality control methods to characterize VLP production at a large scale to accelerate new recombinant vaccine production technologies.
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Affiliation(s)
- Jesús Lavado-García
- Grup d'Enginyeria Cel·lular i Bioprocessos, Department of Chemical, Biological and Environmental Engineering, Escola d'Enginyeria, Universitat Autònoma de Barcelona, Campus de Bellaterra, Cerdanyola del Vallès, Barcelona, Spain
| | - Inmaculada Jorge
- Laboratory of Cardiovascular Proteomics, Vascular Physiopathology area, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Melchor Fernández Almagro 3, Madrid, Spain.,CIBER de Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain
| | - Arnau Boix-Besora
- Grup d'Enginyeria Cel·lular i Bioprocessos, Department of Chemical, Biological and Environmental Engineering, Escola d'Enginyeria, Universitat Autònoma de Barcelona, Campus de Bellaterra, Cerdanyola del Vallès, Barcelona, Spain
| | - Jesús Vázquez
- Laboratory of Cardiovascular Proteomics, Vascular Physiopathology area, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Melchor Fernández Almagro 3, Madrid, Spain.,CIBER de Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain
| | - Francesc Gòdia
- Grup d'Enginyeria Cel·lular i Bioprocessos, Department of Chemical, Biological and Environmental Engineering, Escola d'Enginyeria, Universitat Autònoma de Barcelona, Campus de Bellaterra, Cerdanyola del Vallès, Barcelona, Spain
| | - Laura Cervera
- Grup d'Enginyeria Cel·lular i Bioprocessos, Department of Chemical, Biological and Environmental Engineering, Escola d'Enginyeria, Universitat Autònoma de Barcelona, Campus de Bellaterra, Cerdanyola del Vallès, Barcelona, Spain
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Lingappa JR, Lingappa VR, Reed JC. Addressing Antiretroviral Drug Resistance with Host-Targeting Drugs-First Steps towards Developing a Host-Targeting HIV-1 Assembly Inhibitor. Viruses 2021; 13:451. [PMID: 33802145 DOI: 10.3390/v13030451] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 03/02/2021] [Accepted: 03/02/2021] [Indexed: 12/13/2022] Open
Abstract
The concerning increase in HIV-1 resistance argues for prioritizing the development of host-targeting antiviral drugs because such drugs can offer high genetic barriers to the selection of drug-resistant viral variants. Targeting host proteins could also yield drugs that act on viral life cycle events that have proven elusive to inhibition, such as intracellular events of HIV-1 immature capsid assembly. Here, we review small molecule inhibitors identified primarily through HIV-1 self-assembly screens and describe how all act either narrowly post-entry or broadly on early and late events of the HIV-1 life cycle. We propose that a different screening approach could identify compounds that specifically inhibit HIV-1 Gag assembly, as was observed when a potent rabies virus inhibitor was identified using a host-catalyzed rabies assembly screen. As an example of this possibility, we discuss an antiretroviral small molecule recently identified using a screen that recapitulates the host-catalyzed HIV-1 capsid assembly pathway. This chemotype potently blocks HIV-1 replication in T cells by specifically inhibiting immature HIV-1 capsid assembly but fails to select for resistant viral variants over 37 passages, suggesting a host protein target. Development of such small molecules could yield novel host-targeting antiretroviral drugs and provide insight into chronic diseases resulting from dysregulation of host machinery targeted by these drugs.
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Saffarian S. Application of Advanced Light Microscopy to the Study of HIV and Its Interactions with the Host. Viruses 2021; 13:223. [PMID: 33535486 DOI: 10.3390/v13020223] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 01/26/2021] [Accepted: 01/27/2021] [Indexed: 11/24/2022] Open
Abstract
This review highlights the significant observations of human immunodeficiency virus (HIV) assembly, release and maturation made possible with advanced light microscopy techniques. The advances in technology which now enables these light microscopy measurements are discussed with special emphasis on live imaging approaches including Total Internal Reflection Fluorescence (TIRF), high-resolution light microscopy techniques including PALM and STORM and single molecule measurements, including Fluorescence Resonance Energy Transfer (FRET). The review concludes with a discussion on what new insights and understanding can be expected from these measurements.
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Castro-Gonzalez S, Shi Y, Colomer-Lluch M, Song Y, Mowery K, Almodovar S, Bansal A, Kirchhoff F, Sparrer K, Liang C, Serra-Moreno R. HIV-1 Nef counteracts autophagy restriction by enhancing the association between BECN1 and its inhibitor BCL2 in a PRKN-dependent manner. Autophagy 2021; 17:553-577. [PMID: 32097085 PMCID: PMC8007141 DOI: 10.1080/15548627.2020.1725401] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 01/20/2020] [Accepted: 01/24/2020] [Indexed: 12/20/2022] Open
Abstract
Macroautophagy/autophagy is an auto-digestive pro-survival pathway activated in response to stress to target cargo for lysosomal degradation. In recent years, autophagy has become prominent as an innate antiviral defense mechanism through multiple processes, such as targeting virions and viral components for elimination. These exciting findings have encouraged studies on the ability of autophagy to restrict HIV. However, the role of autophagy in HIV infection remains unclear. Whereas some reports indicate that autophagy is detrimental for HIV, others have claimed that HIV deliberately activates this pathway to increase its infectivity. Moreover, these contrasting findings seem to depend on the cell type investigated. Here, we show that autophagy poses a hurdle for HIV replication, significantly reducing virion production. However, HIV-1 uses its accessory protein Nef to counteract this restriction. Previous studies have indicated that Nef affects autophagy maturation by preventing the fusion between autophagosomes and lysosomes. Here, we uncover that Nef additionally blocks autophagy initiation by enhancing the association between BECN1 and its inhibitor BCL2, and this activity depends on the cellular E3 ligase PRKN. Remarkably, the ability of Nef to counteract the autophagy block is more frequently observed in pandemic HIV-1 and its simian precursor SIVcpz infecting chimpanzees than in HIV-2 and its precursor SIVsmm infecting sooty mangabeys. In summary, our findings demonstrate that HIV-1 is susceptible to autophagy restriction and define Nef as the primary autophagy antagonist of this antiviral process.Abbreviations: 3-MA: 3-methyladenine; ACTB: actin, beta; ATG16L1: autophagy related 16 like 1; BCL2: bcl2 apoptosis regulator; BECN1: beclin 1; cDNA: complementary DNA; EGFP: enhanced green fluorescence protein; ER: endoplasmic reticulum; Gag/p55: group-specific antigen; GFP: green fluorescence protein; GST: glutathione S transferase; HA: hemagglutinin; HIV: human immunodeficiency virus; IP: immunoprecipitation; MAP1LC3B/LC3B: microtubule associated protein 1 light chain 3 beta; Nef: negative factor; PRKN: parkin RBR E3 ubiquitin ligase; PtdIns3K: phosphatidylinositol 3 kinase; PtdIns3P: phosphatidylinositol 3 phosphate; PTM: post-translational modification; RT-qPCR: reverse transcription followed by quantitative PCR; RUBCN: rubicon autophagy regulator; SEM: standard error of the mean; SERINC3: serine incorporator 3; SERINC5: serine incorporator 5; SIV: simian immunodeficiency virus; SQSTM1/p62: sequestosome 1; TFEB: transcription factor EB; UVRAG: UV radiation resistance associated gene; VSV: vesicular stomatitis virus; ZFYVE1/DFCP1: zinc finger FYVE-type containing 1.
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Affiliation(s)
- Sergio Castro-Gonzalez
- Biological Sciences, College of Arts and Sciences, Texas Tech University, Lubbock, TX, USA
| | - Yuhang Shi
- Biological Sciences, College of Arts and Sciences, Texas Tech University, Lubbock, TX, USA
| | - Marta Colomer-Lluch
- IrsiCaixa AIDS Research Institute, Germans Trias i Pujol Research Institute, Badalona, Spain
| | - Ying Song
- Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Kaitlyn Mowery
- Biological Sciences, College of Arts and Sciences, Texas Tech University, Lubbock, TX, USA
| | - Sharilyn Almodovar
- Immunology and Molecular Microbiology, Texas Tech Health Sciences Center, Lubbock, TX, USA
| | - Anju Bansal
- Medicine, Infectious Diseases, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Frank Kirchhoff
- Institute of Molecular Virology, University of Ulm, Ulm, Germany
| | | | - Chengyu Liang
- Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Ruth Serra-Moreno
- Biological Sciences, College of Arts and Sciences, Texas Tech University, Lubbock, TX, USA
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Yeo JY, Koh DWS, Yap P, Goh GR, Gan SKE. Spontaneous Mutations in HIV-1 Gag, Protease, RT p66 in the First Replication Cycle and How They Appear: Insights from an In Vitro Assay on Mutation Rates and Types. Int J Mol Sci 2020; 22:E370. [PMID: 33396460 PMCID: PMC7796399 DOI: 10.3390/ijms22010370] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 12/25/2020] [Accepted: 12/29/2020] [Indexed: 02/07/2023] Open
Abstract
While drug resistant mutations in HIV-1 are largely credited to its error prone HIV-1 RT, the time point in the infection cycle that these mutations can arise and if they appear spontaneously without selection pressures both remained enigmatic. Many HIV-1 RT mutational in vitro studies utilized reporter genes (LacZ) as a template to investigate these questions, thereby not accounting for the possible contribution of viral codon usage. To address this gap, we investigated HIV-1 RT mutation rates and biases on its own Gag, protease, and RT p66 genes in an in vitro selection pressure free system. We found rare clinical mutations with a general avoidance of crucial functional sites in the background mutations rates for Gag, protease, and RT p66 at 4.71 × 10-5, 6.03 × 10-5, and 7.09 × 10-5 mutations/bp, respectively. Gag and p66 genes showed a large number of 'A to G' mutations. Comparisons with silently mutated p66 sequences showed an increase in mutation rates (1.88 × 10-4 mutations/bp) and that 'A to G' mutations occurred in regions reminiscent of ADAR neighbor sequence preferences. Mutational free energies of the 'A to G' mutations revealed an avoidance of destabilizing effects, with the natural p66 gene codon usage providing barriers to disruptive amino acid changes. Our study demonstrates the importance of studying mutation emergence in HIV genes in a RT-PCR in vitro selection pressure free system to understand how fast drug resistance can emerge, providing transferable applications to how new viral diseases and drug resistances can emerge.
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Affiliation(s)
- Joshua Yi Yeo
- Bioinformatics Institute, A*STAR, 30 Biopolis Street, #07-01 Matrix, Singapore 138671, Singapore; (J.Y.Y.); (D.W.-S.K.); (P.Y.); (G.-R.G.)
- Experimental Drug Development Centre, A*STAR, 10 Biopolis Road Chromos #05-01, Singapore 138670, Singapore
| | - Darius Wen-Shuo Koh
- Bioinformatics Institute, A*STAR, 30 Biopolis Street, #07-01 Matrix, Singapore 138671, Singapore; (J.Y.Y.); (D.W.-S.K.); (P.Y.); (G.-R.G.)
- Experimental Drug Development Centre, A*STAR, 10 Biopolis Road Chromos #05-01, Singapore 138670, Singapore
| | - Ping Yap
- Bioinformatics Institute, A*STAR, 30 Biopolis Street, #07-01 Matrix, Singapore 138671, Singapore; (J.Y.Y.); (D.W.-S.K.); (P.Y.); (G.-R.G.)
| | - Ghin-Ray Goh
- Bioinformatics Institute, A*STAR, 30 Biopolis Street, #07-01 Matrix, Singapore 138671, Singapore; (J.Y.Y.); (D.W.-S.K.); (P.Y.); (G.-R.G.)
| | - Samuel Ken-En Gan
- Bioinformatics Institute, A*STAR, 30 Biopolis Street, #07-01 Matrix, Singapore 138671, Singapore; (J.Y.Y.); (D.W.-S.K.); (P.Y.); (G.-R.G.)
- Experimental Drug Development Centre, A*STAR, 10 Biopolis Road Chromos #05-01, Singapore 138670, Singapore
- p53 Laboratory, A*STAR, 8A Biomedical Grove, #06-04/05 Neuros/Immunos, Singapore 138648, Singapore
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Meusser B, Purfuerst B, Luft FC. HIV-1 Gag release from yeast reveals ESCRT interaction with the Gag N-terminal protein region. J Biol Chem 2020; 295:17950-17972. [PMID: 32994219 PMCID: PMC7939435 DOI: 10.1074/jbc.ra120.014710] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 09/25/2020] [Indexed: 11/30/2022] Open
Abstract
The HIV-1 protein Gag assembles at the plasma membrane and drives virion budding, assisted by the cellular endosomal complex required for transport (ESCRT) proteins. Two ESCRT proteins, TSG101 and ALIX, bind to the Gag C-terminal p6 peptide. TSG101 binding is important for efficient HIV-1 release, but how ESCRTs contribute to the budding process and how their activity is coordinated with Gag assembly is poorly understood. Yeast, allowing genetic manipulation that is not easily available in human cells, has been used to characterize the cellular ESCRT function. Previous work reported Gag budding from yeast spheroplasts, but Gag release was ESCRT-independent. We developed a yeast model for ESCRT-dependent Gag release. We combined yeast genetics and Gag mutational analysis with Gag-ESCRT binding studies and the characterization of Gag-plasma membrane binding and Gag release. With our system, we identified a previously unknown interaction between ESCRT proteins and the Gag N-terminal protein region. Mutations in the Gag-plasma membrane-binding matrix domain that reduced Gag-ESCRT binding increased Gag-plasma membrane binding and Gag release. ESCRT knockout mutants showed that the release enhancement was an ESCRT-dependent effect. Similarly, matrix mutation enhanced Gag release from human HEK293 cells. Release enhancement partly depended on ALIX binding to p6, although binding site mutation did not impair WT Gag release. Accordingly, the relative affinity for matrix compared with p6 in GST-pulldown experiments was higher for ALIX than for TSG101. We suggest that a transient matrix-ESCRT interaction is replaced when Gag binds to the plasma membrane. This step may activate ESCRT proteins and thereby coordinate ESCRT function with virion assembly.
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Affiliation(s)
- Birgit Meusser
- Charité Medical Faculty, Berlin, Germany; Max-Delbrück-Center for Molecular Medicine, Berlin, Germany
| | | | - Friedrich C Luft
- Charité Medical Faculty, Berlin, Germany; Max-Delbrück-Center for Molecular Medicine, Berlin, Germany; Experimental and Clinical Research Center, Berlin, Germany.
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Groves NS, Bruns MM, van Engelenburg SB. A Quantitative Live-Cell Superresolution Imaging Framework for Measuring the Mobility of Single Molecules at Sites of Virus Assembly. Pathogens 2020; 9:pathogens9110972. [PMID: 33233482 PMCID: PMC7700196 DOI: 10.3390/pathogens9110972] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 11/13/2020] [Accepted: 11/18/2020] [Indexed: 12/11/2022] Open
Abstract
The insurgence of superresolution microscopy into the fields of virology and microbiology has begun to enable the mapping of molecular assemblies critical for host–pathogen interfaces that organize on a scale below the resolution limit of the light microscope. It is, however, challenging to completely understand the molecular interactions between host and pathogen from strictly time-invariant observations. Herein, we describe a method using simultaneous dual-color superresolution microscopy to gain both structural and dynamic information about HIV-1 assembly. Specifically, we demonstrate the reconstruction of single virus assembly sites using live-cell photo-activated localization microscopy (PALM) while concurrently assessing the sub-viral mobility of the HIV-1 envelope glycoprotein during interaction with the viral lattice. We propose that our method is broadly applicable to elucidating pathogen and host protein–protein interactions through quantification of the dynamics of these proteins at the nanoscale.
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Datir R, Kemp S, El Bouzidi K, Mlchocova P, Goldstein R, Breuer J, Towers GJ, Jolly C, Quiñones-Mateu ME, Dakum PS, Ndembi N, Gupta RK. In Vivo Emergence of a Novel Protease Inhibitor Resistance Signature in HIV-1 Matrix. mBio 2020; 11:e02036-20. [PMID: 33144375 PMCID: PMC7642677 DOI: 10.1128/mbio.02036-20] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 09/21/2020] [Indexed: 12/16/2022] Open
Abstract
Protease inhibitors (PIs) are the second- and last-line therapy for the majority of HIV-infected patients worldwide. Only around 20% of individuals who fail PI regimens develop major resistance mutations in protease. We sought to explore the role of mutations in gag-pro genotypic and phenotypic changes in viruses from six Nigerian patients who failed PI-based regimens without known drug resistance-associated protease mutations in order to identify novel determinants of PI resistance. Target enrichment and next-generation sequencing (NGS) with the Illumina MiSeq system were followed by haplotype reconstruction. Full-length Gag-protease gene regions were amplified from baseline (pre-PI) and virologic failure (VF) samples, sequenced, and used to construct gag-pro-pseudotyped viruses. Phylogenetic analysis was performed using maximum-likelihood methods. Susceptibility to lopinavir (LPV) and darunavir (DRV) was measured using a single-cycle replication assay. Western blotting was used to analyze Gag cleavage. In one of six participants (subtype CRF02_AG), we found 4-fold-lower LPV susceptibility in viral clones during failure of second-line treatment. A combination of four mutations (S126del, H127del, T122A, and G123E) in the p17 matrix of baseline virus generated a similar 4-fold decrease in susceptibility to LPV but not darunavir. These four amino acid changes were also able to confer LPV resistance to a subtype B Gag-protease backbone. Western blotting demonstrated significant Gag cleavage differences between sensitive and resistant isolates in the presence of drug. Resistant viruses had around 2-fold-lower infectivity than sensitive clones in the absence of drug. NGS combined with haplotype reconstruction revealed that resistant, less fit clones emerged from a minority population at baseline and thereafter persisted alongside sensitive fitter viruses. We used a multipronged genotypic and phenotypic approach to document emergence and temporal dynamics of a novel protease inhibitor resistance signature in HIV-1 matrix, revealing the interplay between Gag-associated resistance and fitness.
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Affiliation(s)
| | - Steven Kemp
- University College London, London, United Kingdom
| | | | - Petra Mlchocova
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | | | - Judy Breuer
- University College London, London, United Kingdom
| | | | - Clare Jolly
- University College London, London, United Kingdom
| | | | - Patrick S Dakum
- Institute for Human Virology, Abuja, Nigeria
- Institute of Human Virology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Nicaise Ndembi
- Institute for Human Virology, Abuja, Nigeria
- Institute of Human Virology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Ravindra K Gupta
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
- Africa Health Research Institute, Durban, South Africa
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Guo C, Yao X, Wang K, Wang J, Wang Y. Comparison of HIV-1 Gag and NCp7 in their selectivity for package signal, affinity for stem-loop 3, and Zn 2+ content. Biochimie 2020; 179:135-145. [PMID: 32987107 DOI: 10.1016/j.biochi.2020.09.024] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 09/22/2020] [Accepted: 09/23/2020] [Indexed: 11/17/2022]
Abstract
The human immunodeficiency virus type 1 (HIV-1) Gag recognizes viral packaging signal (Psi) specifically via its nucleocapsid (NC) domain, resulting in the encapsidation of two copies of genomic RNA (gRNA) into the viral particle. The NCp7, which is cleaved from Gag during viral maturation, is a nucleic acid chaperone, coating and protecting the gRNA. In this study, an RT-qPCR-based approach was developed to quantitatively compare the Psi-selectivity of Gag and NCp7 in the presence of bacterial or 293T total RNAs. The binding affinity of Gag and NCp7 to the stem-loop (SL) 3 of Psi was also compared using surface plasmon resonance. We found that Gag selected more Psi-RNA than NCp7 from both E. coli BL21 (DE3) and in vitro binding reactions, and Gag bound to SL3-RNA with a higher affinity than NCp7. Moreover, Gag contained two Zn2+ whereas NCp7 contained one. The N-terminal zinc-finger motif of NCp7 lost most of its Zn2+-binding activity. Deletion of N-terminal amino acids 1-11 of NCp7 resulted in increased Psi-selectivity, SL3-affinity and Zn2+ content. These results indicated that Zn2+ coordination of Gag is critical for Psi-binding and selection. Removal of Zn2+ from the first zinc-finger motif during or after Gag cleavage to generate mature NCp7 might serve as a switch to regulate the functions of Gag NC domain and mature NCp7. Our study will be helpful to elucidate the important roles that Zn2+ plays in the viral life cycle, and may benefit further investigations of the function of HIV-1 Gag and NCp7.
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Affiliation(s)
- Chao Guo
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, 23 Hongda Street, TEDA, Tianjin, 300457, China
| | - Xiaohong Yao
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, 23 Hongda Street, TEDA, Tianjin, 300457, China
| | - Kangkang Wang
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, 23 Hongda Street, TEDA, Tianjin, 300457, China
| | - Jinzhong Wang
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, 23 Hongda Street, TEDA, Tianjin, 300457, China; Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, 23 Hongda Street, TEDA, Tianjin, 300457, China; Tianjin Key Laboratory of Microbial Functional Genomics, 23 Hongda Street, TEDA, Tianjin, 300457, China.
| | - Ying Wang
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, 23 Hongda Street, TEDA, Tianjin, 300457, China; Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, 23 Hongda Street, TEDA, Tianjin, 300457, China; Tianjin Key Laboratory of Microbial Functional Genomics, 23 Hongda Street, TEDA, Tianjin, 300457, China.
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Abstract
Since the emergence of HIV and AIDS in the early 1980s, the development of safe and effective therapies has accompanied a massive increase in our understanding of the fundamental processes that drive HIV biology. As basic HIV research has informed the development of novel therapies, HIV inhibitors have been used as probes for investigating basic mechanisms of HIV-1 replication, transmission, and pathogenesis. This positive feedback cycle has led to the development of highly effective combination antiretroviral therapy (cART), which has helped stall the progression to AIDS, prolong lives, and reduce transmission of the virus. However, to combat the growing rates of virologic failure and toxicity associated with long-term therapy, it is important to diversify our repertoire of HIV-1 treatments by identifying compounds that block additional steps not targeted by current drugs. Most of the available therapeutics disrupt early events in the replication cycle, with the exception of the protease (PR) inhibitors, which act at the virus maturation step. HIV-1 maturation consists of a series of biochemical changes that facilitate the conversion of an immature, noninfectious particle to a mature infectious virion. These changes include proteolytic processing of the Gag polyprotein by the viral protease (PR), structural rearrangement of the capsid (CA) protein, and assembly of individual CA monomers into hexamers and pentamers that ultimately form the capsid. Here, we review the development and therapeutic potential of maturation inhibitors (MIs), an experimental class of anti-HIV-1 compounds with mechanisms of action distinct from those of the PR inhibitors. We emphasize the key insights into HIV-1 biology and structure that the study of MIs has provided. We will focus on three distinct groups of inhibitors that block HIV-1 maturation: (1) compounds that block the processing of the CA-spacer peptide 1 (SP1) cleavage intermediate, the original class of compounds to which the term MI was applied; (2) CA-binding inhibitors that disrupt capsid condensation; and (3) allosteric integrase inhibitors (ALLINIs) that block the packaging of the viral RNA genome into the condensing capsid during maturation. Although these three classes of compounds have distinct structures and mechanisms of action, they share the ability to block the formation of the condensed conical capsid, thereby blocking particle infectivity.
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Affiliation(s)
| | - Eric O. Freed
- HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA;
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Rice BL, Stake MS, Parent LJ. TNPO3-Mediated Nuclear Entry of the Rous Sarcoma Virus Gag Protein Is Independent of the Cargo-Binding Domain. J Virol 2020; 94:e00640-20. [PMID: 32581109 DOI: 10.1128/JVI.00640-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2020] [Accepted: 06/16/2020] [Indexed: 11/20/2022] Open
Abstract
Retroviral Gag polyproteins orchestrate the assembly and release of nascent virus particles from the plasma membranes of infected cells. Although it was traditionally thought that Gag proteins trafficked directly from the cytosol to the plasma membrane, we discovered that the oncogenic avian alpharetrovirus Rous sarcoma virus (RSV) Gag protein undergoes transient nucleocytoplasmic transport as an intrinsic step in virus assembly. Using a genetic approach in yeast, we identified three karyopherins that engage the two independent nuclear localization signals (NLSs) in Gag. The primary NLS is in the nucleocapsid (NC) domain of Gag and binds directly to importin-α, which recruits importin-β to mediate nuclear entry. The second NLS (TNPO3), which resides in the matrix (MA) domain, is dependent on importin-11 and transportin-3 (TNPO3), which are known as MTR10p and Kap120p in yeast, although it is not clear whether these import factors are independent or additive. The functions of importin-α/importin-β and importin-11 have been verified in avian cells, whereas the role of TNPO3 has not been studied. In this report, we demonstrate that TNPO3 directly binds to Gag and mediates its nuclear entry. To our surprise, this interaction did not require the cargo-binding domain (CBD) of TNPO3, which typically mediates nuclear entry for other binding partners of TNPO3, including SR domain-containing splicing factors and tRNAs that reenter the nucleus. These results suggest that RSV hijacks this host nuclear import pathway using a unique mechanism, potentially allowing other cargo to simultaneously bind TNPO3.IMPORTANCE RSV Gag nuclear entry is facilitated using three distinct host import factors that interact with nuclear localization signals in the Gag MA and NC domains. Here, we show that the MA region is required for nuclear import of Gag through the TNPO3 pathway. Gag nuclear entry does not require the CBD of TNPO3. Understanding the molecular basis for TNPO3-mediated nuclear trafficking of the RSV Gag protein may lead to a deeper appreciation for whether different import factors play distinct roles in retrovirus replication.
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45
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Klingler J, Anton H, Réal E, Zeiger M, Moog C, Mély Y, Boutant E. How HIV-1 Gag Manipulates Its Host Cell Proteins: A Focus on Interactors of the Nucleocapsid Domain. Viruses 2020; 12:E888. [PMID: 32823718 DOI: 10.3390/v12080888] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [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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46
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Sarni S, Biswas B, Liu S, Olson ED, Kitzrow JP, Rein A, Wysocki VH, Musier-Forsyth K. HIV-1 Gag protein with or without p6 specifically dimerizes on the viral RNA packaging signal. J Biol Chem 2020; 295:14391-14401. [PMID: 32817318 DOI: 10.1074/jbc.ra120.014835] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 08/10/2020] [Indexed: 02/04/2023] Open
Abstract
The HIV-1 Gag protein is responsible for genomic RNA (gRNA) packaging and immature viral particle assembly. Although the presence of gRNA in virions is required for viral infectivity, in its absence, Gag can assemble around cellular RNAs and form particles resembling gRNA-containing particles. When gRNA is expressed, it is selectively packaged despite the presence of excess host RNA, but how it is selectively packaged is not understood. Specific recognition of a gRNA packaging signal (Psi) has been proposed to stimulate the efficient nucleation of viral assembly. However, the heterogeneity of Gag-RNA interactions renders capturing this transient nucleation complex using traditional structural biology approaches challenging. Here, we used native MS to investigate RNA binding of wild-type (WT) Gag and Gag lacking the p6 domain (GagΔp6). Both proteins bind to Psi RNA primarily as dimers, but to a control RNA primarily as monomers. The dimeric complexes on Psi RNA require an intact dimer interface within Gag. GagΔp6 binds to Psi RNA with high specificity in vitro and also selectively packages gRNA in particles produced in mammalian cells. These studies provide direct support for the idea that Gag binding to Psi specifically promotes nucleation of Gag-Gag interactions at the early stages of immature viral particle assembly in a p6-independent manner.
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Affiliation(s)
- Samantha Sarni
- Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio, USA.,Resource for Native Mass Spectrometry Guided Structural Biology, The Ohio State University, Columbus, Ohio, USA.,Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA
| | - Banhi Biswas
- HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, Frederick, Maryland, USA
| | - Shuohui Liu
- Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA.,Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio, USA.,Center for Retrovirus Research, The Ohio State University, Columbus, Ohio, USA
| | - Erik D Olson
- Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio, USA.,Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA.,Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio, USA.,Center for Retrovirus Research, The Ohio State University, Columbus, Ohio, USA
| | - Jonathan P Kitzrow
- Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio, USA.,Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA.,Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio, USA.,Center for Retrovirus Research, The Ohio State University, Columbus, Ohio, USA
| | - Alan Rein
- HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, Frederick, Maryland, USA
| | - Vicki H Wysocki
- Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio, USA .,Resource for Native Mass Spectrometry Guided Structural Biology, The Ohio State University, Columbus, Ohio, USA.,Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA.,Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio, USA
| | - Karin Musier-Forsyth
- Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio, USA .,Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA.,Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio, USA.,Center for Retrovirus Research, The Ohio State University, Columbus, Ohio, USA
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47
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Gallinaro A, Borghi M, Pirillo MF, Cecchetti S, Bona R, Canitano A, Michelini Z, Di Virgilio A, Olvera A, Brander C, Negri D, Cara A. Development and Preclinical Evaluation of an Integrase Defective Lentiviral Vector Vaccine Expressing the HIVACAT T Cell Immunogen in Mice. Mol Ther Methods Clin Dev 2020; 17:418-428. [PMID: 32154327 PMCID: PMC7056611 DOI: 10.1016/j.omtm.2020.01.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Accepted: 01/22/2020] [Indexed: 12/25/2022]
Abstract
Cellular immune responses play a fundamental role in controlling viral replication and AIDS progression in human immunodeficiency virus (HIV)-infected subjects and in simian immunodeficiency virus (SIV)-infected macaques. Integrase defective lentiviral vector (IDLV) represents a promising vaccine candidate, inducing functional and durable immune responses in mice and non-human primates. Here, we designed HIV- and SIV-based IDLVs to express the HIVACAT T cell immunogen (HTI), a mosaic antigen designed to cover vulnerable sites in HIV-1 Gag, Pol, Vif, and Nef. We observed that HTI expression during lentiviral vector production interfered profoundly with IDLV particles release because of sequestration of both HIV- and SIV-Gag proteins in the cytoplasm of the vector-producing cells. However, modifications in IDLV design and vector production procedures greatly improved recovery of both HIV- and SIV-based IDLV-HTI. Immunization experiments in BALB/c mice showed that both IDLVs elicited HTI-specific T cell responses. However, immunization with HIV-based IDLV elicited also a T cell response toward exogenous HIV proteins in IDLV particles, suggesting that SIV-based IDLV may be a preferable platform to assess the induction of transgene-specific immune responses against rationally designed HIV structural antigens. These data support the further evaluation of IDLV as an effective platform of T cell immunogens for the development of an effective HIV vaccine.
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Affiliation(s)
| | - Martina Borghi
- Department of Infectious Diseases, Istituto Superiore di Sanità, Rome, Italy
| | | | - Serena Cecchetti
- Confocal Microscopy Unit NMR, Confocal Microscopy Area Core Facilities, Istituto Superiore di Sanità, Rome, Italy
| | - Roberta Bona
- National Center for Global Health, Istituto Superiore di Sanità, Rome, Italy
| | - Andrea Canitano
- National Center for Global Health, Istituto Superiore di Sanità, Rome, Italy
| | - Zuleika Michelini
- National Center for Global Health, Istituto Superiore di Sanità, Rome, Italy
| | - Antonio Di Virgilio
- Center for Animal Research and Welfare, Istituto Superiore di Sanità, Rome, Italy
| | - Alex Olvera
- Irsicaixa AIDS Research Institute, 08916 Badalona, Catalonia, Spain
- Universitat de Vic-Universitat Central de Catalunya (UVic-UCC), 08500 Vic, Barcelona, Spain
| | - Christian Brander
- Irsicaixa AIDS Research Institute, 08916 Badalona, Catalonia, Spain
- Universitat de Vic-Universitat Central de Catalunya (UVic-UCC), 08500 Vic, Barcelona, Spain
- ICREA, Pg. Lluís Companys 23, 08010 Barcelona, Spain
- AELIX Therapeutics, Barcelona, Spain
| | - Donatella Negri
- Department of Infectious Diseases, Istituto Superiore di Sanità, Rome, Italy
| | - Andrea Cara
- National Center for Global Health, Istituto Superiore di Sanità, Rome, Italy
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48
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Murphy RE, Saad JS. The Interplay between HIV-1 Gag Binding to the Plasma Membrane and Env Incorporation. Viruses 2020; 12:E548. [PMID: 32429351 PMCID: PMC7291237 DOI: 10.3390/v12050548] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 05/14/2020] [Accepted: 05/14/2020] [Indexed: 12/21/2022] Open
Abstract
Advancement in drug therapies and patient care have drastically improved the mortality rates of HIV-1 infected individuals. Many of these therapies were developed or improved upon by using structure-based techniques, which underscore the importance of understanding essential mechanisms in the replication cycle of HIV-1 at the structural level. One such process which remains poorly understood is the incorporation of the envelope glycoprotein (Env) into budding virus particles. Assembly of HIV particles is initiated by targeting of the Gag polyproteins to the inner leaflet of the plasma membrane (PM), a process mediated by the N-terminally myristoylated matrix (MA) domain and phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2). There is strong evidence that formation of the Gag lattice on the PM is a prerequisite for the incorporation of Env into budding particles. It is also suggested that Env incorporation is mediated by an interaction between its cytoplasmic tail (gp41CT) and the MA domain of Gag. In this review, we highlight the latest developments and current efforts to understand the interplay between gp41CT, MA, and the membrane during assembly. Elucidation of the molecular determinants of Gag-Env-membrane interactions may help in the development of new antiviral therapeutic agents that inhibit particle assembly, Env incorporation and ultimately virus production.
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Affiliation(s)
| | - Jamil S. Saad
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA;
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49
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McCauley MJ, Rouzina I, Li J, Núñez ME, Williams MC. Significant Differences in RNA Structure Destabilization by HIV-1 GagDp6 and NCp7 Proteins. Viruses 2020; 12:E484. [PMID: 32344834 DOI: 10.3390/v12050484] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [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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50
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Dai YD, Dias P, Margosiak A, Marquardt K, Bashratyan R, Hu WY, Haskins K, Evans LH. Endogenous retrovirus Gag antigen and its gene variants are unique autoantigens expressed in the pancreatic islets of non-obese diabetic mice. Immunol Lett 2020; 223:62-70. [PMID: 32335144 DOI: 10.1016/j.imlet.2020.04.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 04/09/2020] [Accepted: 04/14/2020] [Indexed: 12/16/2022]
Abstract
Endogenous retrovirus (ERV) are remnants of ancient retroviruses that have been incorporated into the genome and evidence suggests that they may play a role in the etiology of T1D. We previously identified a murine leukemia retrovirus-like ERV whose Env and Gag antigens are involved in autoimmune responses in non-obese diabetic (NOD) mice. In this study, we show that the Gag antigen is present in the islet stromal cells. Although Gag gene transcripts were present, Gag protein was not detected in diabetes-resistant mice. Cloning and sequencing analysis of individual Gag genes revealed that NOD islets express Gag gene variants with complete open-reading frames (ORFs), in contrast to the diabetes-resistant mice, whose islet Gag gene transcripts are mostly non-ORFs. Importantly, the ORFs obtained from the NOD islets are extremely heterogenous, coding for various mutants that are absence in the genome. We further show that Gag antigens are stimulatory for autoreactive T cells and identified one islet-expressing Gag variant that contains an altered peptide ligand capable of inducing IFN-gamma release by the T cells. The data highlight a unique retrovirus-like factor in the islets of the NOD mouse strain, which may participate in key events triggering autoimmunity and T1D.
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Affiliation(s)
- Yang D Dai
- Biomedical Research Institute of Southern California, Oceanside, CA, USA; Department of Immunology, Scripps Research, San Diego, CA, USA.
| | - Peter Dias
- Biomedical Research Institute of Southern California, Oceanside, CA, USA
| | - Amanda Margosiak
- Biomedical Research Institute of Southern California, Oceanside, CA, USA
| | | | | | | | - Kathryn Haskins
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Denver, CO, USA
| | - Leonard H Evans
- Laboratory of Persistent Viral Diseases, National Institute of Allergy and Infectious Diseases, Hamilton, MT, USA
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