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Tipo J, Gottipati K, Slaton M, Gonzalez-Gutierrez G, Choi KH. Structure of HIV-1 RRE stem-loop II identifies two conformational states of the high-affinity Rev binding site. Nat Commun 2024; 15:4198. [PMID: 38760344 PMCID: PMC11101469 DOI: 10.1038/s41467-024-48162-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Accepted: 04/22/2024] [Indexed: 05/19/2024] Open
Abstract
During HIV infection, specific RNA-protein interaction between the Rev response element (RRE) and viral Rev protein is required for nuclear export of intron-containing viral mRNA transcripts. Rev initially binds the high-affinity site in stem-loop II, which promotes oligomerization of additional Rev proteins on RRE. Here, we present the crystal structure of RRE stem-loop II in distinct closed and open conformations. The high-affinity Rev-binding site is located within the three-way junction rather than the predicted stem IIB. The closed and open conformers differ in their non-canonical interactions within the three-way junction, and only the open conformation has the widened major groove conducive to initial Rev interaction. Rev binding assays show that RRE stem-loop II has high- and low-affinity binding sites, each of which binds a Rev dimer. We propose a binding model, wherein Rev-binding sites on RRE are sequentially created through structural rearrangements induced by Rev-RRE interactions.
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Affiliation(s)
- Jerricho Tipo
- Department of Pharmacology and Toxicology, The University of Texas Medical Branch, Galveston, TX, 77555, USA
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN, 47405, USA
| | - Keerthi Gottipati
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN, 47405, USA
| | - Michael Slaton
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN, 47405, USA
| | | | - Kyung H Choi
- Department of Pharmacology and Toxicology, The University of Texas Medical Branch, Galveston, TX, 77555, USA.
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN, 47405, USA.
- Department of Biochemistry and Molecular Biology, Sealy Center for Structural Biology, The University of Texas Medical Branch, Galveston, TX, 77555, USA.
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2
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Pavesi A, Romerio F. Creation of the HIV-1 antisense gene asp coincided with the emergence of the pandemic group M and is associated with faster disease progression. Microbiol Spectr 2024; 12:e0380223. [PMID: 38230940 PMCID: PMC10846101 DOI: 10.1128/spectrum.03802-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Accepted: 12/19/2023] [Indexed: 01/18/2024] Open
Abstract
Despite being first identified more than three decades ago, the antisense gene asp of HIV-1 remains an enigma. asp is present uniquely in pandemic (group M) HIV-1 strains, and it is absent in all non-pandemic (out-of-M) HIV-1 strains and virtually all non-human primate lentiviruses. This suggests that the creation of asp may have contributed to HIV-1 fitness or worldwide spread. It also raises the question of which evolutionary processes were at play in the creation of asp. Here, we show that HIV-1 genomes containing an intact asp gene are associated with faster HIV-1 disease progression. Furthermore, we demonstrate that the creation of a full-length asp gene occurred via the evolution of codon usage in env overlapping asp on the opposite strand. This involved differential use of synonymous codons or conservative amino acid substitution in env that eliminated internal stop codons in asp, and redistribution of synonymous codons in env that minimized the likelihood of new premature stops arising in asp. Nevertheless, the creation of a full-length asp gene reduced the genetic diversity of env. The Luria-Delbruck fluctuation test suggests that the interrupted asp open reading frame (ORF) is the progenitor of the intact ORF, rather than a descendant under random genetic drift. Therefore, the existence of group-M isolates with a truncated asp ORF indicates an incomplete transition process. For the first time, our study links the presence of a full-length asp ORF to faster disease progression, thus warranting further investigation into the cellular processes and molecular mechanisms through which the ASP protein impacts HIV-1 replication, transmission, and pathogenesis.IMPORTANCEOverlapping genes engage in a tug-of-war, constraining each other's evolution. The creation of a new gene overlapping an existing one comes at an evolutionary cost. Thus, its conservation must be advantageous, or it will be lost, especially if the pre-existing gene is essential for the viability of the virus or cell. We found that the creation and conservation of the HIV-1 antisense gene asp occurred through differential use of synonymous codons or conservative amino acid substitutions within the overlapping gene, env. This process did not involve amino acid changes in ENV that benefited its function, but rather it constrained the evolution of ENV. Nonetheless, the creation of asp brought a net selective advantage to HIV-1 because asp is conserved especially among high-prevalence strains. The association between the presence of an intact asp gene and faster HIV-1 disease progression supports that conclusion and warrants further investigation.
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Affiliation(s)
- Angelo Pavesi
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy
| | - Fabio Romerio
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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3
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Behrens RT, Sherer NM. Retroviral hijacking of host transport pathways for genome nuclear export. mBio 2023; 14:e0007023. [PMID: 37909783 PMCID: PMC10746203 DOI: 10.1128/mbio.00070-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2023] Open
Abstract
Recent advances in the study of virus-cell interactions have improved our understanding of how viruses that replicate their genomes in the nucleus (e.g., retroviruses, hepadnaviruses, herpesviruses, and a subset of RNA viruses) hijack cellular pathways to export these genomes to the cytoplasm where they access virion egress pathways. These findings shed light on novel aspects of viral life cycles relevant to the development of new antiviral strategies and can yield new tractable, virus-based tools for exposing additional secrets of the cell. The goal of this review is to summarize defined and emerging modes of virus-host interactions that drive the transit of viral genomes out of the nucleus across the nuclear envelope barrier, with an emphasis on retroviruses that are most extensively studied. In this context, we prioritize discussion of recent progress in understanding the trafficking and function of the human immunodeficiency virus type 1 Rev protein, exemplifying a relatively refined example of stepwise, cooperativity-driven viral subversion of multi-subunit host transport receptor complexes.
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Affiliation(s)
- Ryan T. Behrens
- Department of Pathology and Laboratory Medicine, University of Wisconsin, Madison, Wisconsin, USA
| | - Nathan M. Sherer
- McArdle Laboratory for Cancer Research and Carbone Cancer Center, University of Wisconsin, Madison, Wisconsin, USA
- Institute for Molecular Virology, University of Wisconsin, Madison, Wisconsin, USA
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4
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Jackson PEH, Dzhivhuho G, Rekosh D, Hammarskjold ML. Sequence and Functional Variation in the HIV-1 Rev Regulatory Axis. Curr HIV Res 2021; 18:85-98. [PMID: 31906839 DOI: 10.2174/1570162x18666200106112842] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 11/22/2019] [Accepted: 12/02/2019] [Indexed: 11/22/2022]
Abstract
BACKGROUND To complete its replication cycle, HIV-1 requires the nucleocytoplasmic export of intron-containing viral mRNAs. This process is ordinarily restricted by the cell, but HIV overcomes the block by means of a viral protein, Rev, and an RNA secondary structure found in all unspliced and incompletely spliced viral mRNAs called the Rev Response Element (RRE). In vivo activity of the Rev-RRE axis requires Rev binding to the RRE, oligomerization of Rev to form a competent ribonucleoprotein complex, and recruitment of cellular factors including Crm1 and RanGTP in order to export the targeted transcript. Sequence variability is observed among primary isolates in both Rev and the RRE, and the activity of both can be modulated through relatively small sequence changes. Primary isolates show differences in Rev-RRE activity and a few studies have found a correlation between lower Rev-RRE activity and slower progression of clinical disease. Lower Rev-RRE activity has also been associated with the evasion of cytotoxic T lymphocyte mediated killing. CONCLUSION The HIV-1 Rev-RRE regulatory axis is an understudied mechanism by which viral adaptation to diverse immune milieus may take place. There is evidence that this adaptation plays a role in HIV pathogenesis, particularly in immune evasion and latency, but further studies with larger sample sizes are warranted.
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Affiliation(s)
- Patrick E H Jackson
- Division of Infectious Diseases and International Health, School of Medicine, University of Virginia, Charlottesville, Virginia United States.,Myles H. Thaler Center for HIV and Human Retrovirus Research, University of Virginia, Charlottesville, Virginia, United States
| | - Godfrey Dzhivhuho
- Myles H. Thaler Center for HIV and Human Retrovirus Research, University of Virginia, Charlottesville, Virginia, United States.,Department of Microbiology, Immunology, and Cancer Biology, School of Medicine, University of Virginia, Charlottesville, Virginia, United States
| | - David Rekosh
- Myles H. Thaler Center for HIV and Human Retrovirus Research, University of Virginia, Charlottesville, Virginia, United States.,Department of Microbiology, Immunology, and Cancer Biology, School of Medicine, University of Virginia, Charlottesville, Virginia, United States
| | - Marie-Louise Hammarskjold
- Myles H. Thaler Center for HIV and Human Retrovirus Research, University of Virginia, Charlottesville, Virginia, United States.,Department of Microbiology, Immunology, and Cancer Biology, School of Medicine, University of Virginia, Charlottesville, Virginia, United States
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5
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Wright IA, Bale MJ, Shao W, Hu WS, Coffin JM, Van Zyl GU, Kearney MF. HIVIntact: a python-based tool for HIV-1 genome intactness inference. Retrovirology 2021; 18:16. [PMID: 34176496 PMCID: PMC8237426 DOI: 10.1186/s12977-021-00561-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Accepted: 06/16/2021] [Indexed: 12/18/2022] Open
Abstract
The characterisation of the HIV-1 reservoir, which consists of replication-competent integrated proviruses that persist on antiretroviral therapy (ART), is made difficult by the rarity of intact proviruses relative to those that are defective. While the only conclusive test for the replication-competence of HIV-1 proviruses is carried out in cell culture, genetic characterization of genomes by near full-length (NFL) PCR and sequencing can be used to determine whether particular proviruses have insertions, deletions, or substitutions that render them defective. Proviruses that are not excluded by having such defects can be classified as genetically intact and, possibly, replication competent. Identifying and quantifying proviruses that are potentially replication-competent is important for the development of strategies towards a functional cure. However, to date, there are no programs that can be incorporated into deep-sequencing pipelines for the automated characterization and annotation of HIV genomes. Existing programs that perform this work require manual intervention, cannot be widely installed, and do not have easily adjustable settings. Here, we present HIVIntact, a python-based software tool that characterises genomic defects in NFL HIV-1 sequences, allowing putative intact genomes to be identified in-silico. Unlike other applications that assess the genetic intactness of HIV genomes, this tool can be incorporated into existing sequence-analysis pipelines and applied to large next-generation sequencing datasets. ![]()
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Affiliation(s)
- Imogen A Wright
- Division of Medical Virology, University of Stellenbosch, Tygerberg Hospital, Cape Town, South Africa.
| | - Michael J Bale
- HIV Dynamics and Replication Program, CCR, NCI-Frederick, Frederick, MD, USA.,Weill Cornell Medical College, NY, New York, USA
| | - Wei Shao
- Advanced Biomedical Computing Center, Leidos Biomedical Research, Inc, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Wei-Shau Hu
- HIV Dynamics and Replication Program, CCR, NCI-Frederick, Frederick, MD, USA
| | - John M Coffin
- Department of Molecular Biology and Microbiology, Tufts University, Boston, MA, USA
| | - Gert U Van Zyl
- Division of Medical Virology, University of Stellenbosch, Tygerberg Hospital, Cape Town, South Africa
| | - Mary F Kearney
- HIV Dynamics and Replication Program, CCR, NCI-Frederick, Frederick, MD, USA
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6
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Abstract
The human immunodeficiency virus type 1 (HIV-1) proteome is expressed from alternatively spliced and unspliced genomic RNAs. However, HIV-1 RNAs that are not fully spliced are perceived by the host machinery as defective and are retained in the nucleus. During late infection, HIV-1 bypasses this regulatory mechanism by expression of the Rev protein from a fully spliced mRNA. Once imported into the nucleus, Rev mediates the export of unprocessed HIV-1 RNAs to the cytoplasm, leading to the production of the viral progeny. While regarded as a canonical RNA export factor, Rev has also been linked to HIV-1 RNA translation, stabilization, splicing and packaging. However, Rev's functions beyond RNA export have remained poorly understood. Here, we revisit this paradigmatic protein, reviewing recent data investigating its structure and function. We conclude by asking: what remains unknown about this enigmatic viral protein?
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Affiliation(s)
| | - Aino Järvelin
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Ilan Davis
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Alfredo Castello
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
- MRC-University of Glasgow Centre for Virus Research, University of Glasgow, 464 Bearsden Road, Glasgow G61 1QH, UK
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7
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O'Carroll IP, Fan L, Kroupa T, McShane EK, Theodore C, Yates EA, Kondrup B, Ding J, Martin TS, Rein A, Wang YX. Structural Mimicry Drives HIV-1 Rev-Mediated HERV-K Expression. J Mol Biol 2020; 432:166711. [PMID: 33197463 DOI: 10.1016/j.jmb.2020.11.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 11/09/2020] [Accepted: 11/09/2020] [Indexed: 10/23/2022]
Abstract
Expression of the Human Endogenous Retrovirus Type K (HERV-K), the youngest and most active HERV, has been associated with various cancers and neurodegenerative diseases. As in all retroviruses, a fraction of HERV-K transcripts is exported from the nucleus in unspliced or incompletely spliced forms to serve as templates for translation of viral proteins. In a fraction of HERV-K loci (Type 2 proviruses), nuclear export of the unspliced HERV-K mRNA appears to be mediated by a cis-acting signal on the mRNA, the RcRE, and the protein Rec-these are analogous to the RRE-Rev system in HIV-1. Interestingly, the HIV-1 Rev protein is able to mediate the nuclear export of the HERV-K RcRE, contributing to elevated HERV-K expression in HIV-infected patients. We aimed to understand the structural basis for HIV Rev-HERV-K RcRE recognition. We examined the conformation of the RcRE RNA in solution using small-angle X-ray scattering (SAXS) and atomic force microscopy (AFM). We found that the 433-nt long RcRE can assume folded or extended conformations as observed by AFM. SAXS analysis of a truncated RcRE variant revealed an "A"-shaped topological structure similar to the one previously reported for the HIV-1 RRE. The effect of the overall topology was examined using several deletion variants. SAXS and biochemical analyses demonstrated that the "A" shape is necessary for efficient Rev-RcRE complex formation in vitro and nuclear export activity in cell culture. The findings provide insight into the mechanism of HERV-K expression and a structural explanation for HIV-1 Rev-mediated expression of HERV-K in HIV-infected patients. IMPORTANCE: Expression of the human endogenous retrovirus type K (HERV-K) has been associated with various cancers and autoimmune diseases. Nuclear export of both HIV-1 and HERV-K mRNAs is dependent on the interaction between a small viral protein (Rev in HIV-1 and Rec in HERV-K) and a region on the mRNA (RRE in HIV-1 and RcRE in HERV-K). HIV-1 Rev is able to mediate the nuclear export of RcRE-containing HERV-K mRNAs, which contributes to elevated production of HERV-K proteins in HIV-infected patients. We report the solution conformation of the RcRE RNA-the first three-dimensional topological structure for a HERV molecule-and find that the RcRE resembles the HIV-1 nuclear export signal, RRE. The finding reveals the structural basis for the increased HERV-K expression observed in HIV-infected patients. Elevated HERV expression, mediated by HIV infection or other stressors, can have various HERV-related biological consequences. The findings provide structural insight for regulation of HERV-K expression.
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Affiliation(s)
- Ina P O'Carroll
- Department of Chemistry, United States Naval Academy, Annapolis, MD 21402, USA.
| | - Lixin Fan
- Basic Science Program, Frederick National Laboratory for Cancer Research, SAXS Core Facility of the National Cancer Institute, Frederick, MD 21702, USA
| | - Tomáš Kroupa
- HIV Dynamics and Replication Program, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA
| | - Erin K McShane
- Department of Chemistry, United States Naval Academy, Annapolis, MD 21402, USA
| | - Christophe Theodore
- Department of Chemistry, United States Naval Academy, Annapolis, MD 21402, USA
| | - Elizabeth A Yates
- Department of Chemistry, United States Naval Academy, Annapolis, MD 21402, USA
| | - Benjamin Kondrup
- Department of Chemistry, United States Naval Academy, Annapolis, MD 21402, USA
| | - Jienyu Ding
- Protein-Nucleic Acid Interaction Section, Structural Biophysics Laboratory, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA
| | - Tyler S Martin
- Department of Chemistry, United States Naval Academy, Annapolis, MD 21402, USA
| | - Alan Rein
- HIV Dynamics and Replication Program, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA
| | - Yun-Xing Wang
- Protein-Nucleic Acid Interaction Section, Structural Biophysics Laboratory, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA
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8
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Patro SC, Brandt LD, Bale MJ, Halvas EK, Joseph KW, Shao W, Wu X, Guo S, Murrell B, Wiegand A, Spindler J, Raley C, Hautman C, Sobolewski M, Fennessey CM, Hu WS, Luke B, Hasson JM, Niyongabo A, Capoferri AA, Keele BF, Milush J, Hoh R, Deeks SG, Maldarelli F, Hughes SH, Coffin JM, Rausch JW, Mellors JW, Kearney MF. Combined HIV-1 sequence and integration site analysis informs viral dynamics and allows reconstruction of replicating viral ancestors. Proc Natl Acad Sci U S A 2019; 116:25891-25899. [PMID: 31776247 PMCID: PMC6925994 DOI: 10.1073/pnas.1910334116] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Understanding HIV-1 persistence despite antiretroviral therapy (ART) is of paramount importance. Both single-genome sequencing (SGS) and integration site analysis (ISA) provide useful information regarding the structure of persistent HIV DNA populations; however, until recently, there was no way to link integration sites to their cognate proviral sequences. Here, we used multiple-displacement amplification (MDA) of cellular DNA diluted to a proviral endpoint to obtain full-length proviral sequences and their corresponding sites of integration. We applied this method to lymph node and peripheral blood mononuclear cells from 5 ART-treated donors to determine whether groups of identical subgenomic sequences in the 2 compartments are the result of clonal expansion of infected cells or a viral genetic bottleneck. We found that identical proviral sequences can result from both cellular expansion and viral genetic bottlenecks occurring prior to ART initiation and following ART failure. We identified an expanded T cell clone carrying an intact provirus that matched a variant previously detected by viral outgrowth assays and expanded clones with wild-type and drug-resistant defective proviruses. We also found 2 clones from 1 donor that carried identical proviruses except for nonoverlapping deletions, from which we could infer the sequence of the intact parental virus. Thus, MDA-SGS can be used for "viral reconstruction" to better understand intrapatient HIV-1 evolution and to determine the clonality and structure of proviruses within expanded clones, including those with drug-resistant mutations. Importantly, we demonstrate that identical sequences observed by standard SGS are not always sufficient to establish proviral clonality.
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Affiliation(s)
- Sean C Patro
- HIV Dynamics and Replication Program, National Cancer Institute, Frederick, MD 21702;
| | - Leah D Brandt
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA 15213
| | - Michael J Bale
- HIV Dynamics and Replication Program, National Cancer Institute, Frederick, MD 21702
| | - Elias K Halvas
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA 15213
| | - Kevin W Joseph
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA 15213
| | - Wei Shao
- Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702
| | - Xiaolin Wu
- Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702
| | - Shuang Guo
- Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702
| | - Ben Murrell
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institute, 171 65 Stockholm, Sweden
| | - Ann Wiegand
- HIV Dynamics and Replication Program, National Cancer Institute, Frederick, MD 21702
| | - Jonathan Spindler
- HIV Dynamics and Replication Program, National Cancer Institute, Frederick, MD 21702
| | - Castle Raley
- Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702
| | - Christopher Hautman
- Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702
| | | | - Christine M Fennessey
- AIDS and Cancer Virus Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702
| | - Wei-Shau Hu
- HIV Dynamics and Replication Program, National Cancer Institute, Frederick, MD 21702
| | - Brian Luke
- Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702
| | - Jenna M Hasson
- HIV Dynamics and Replication Program, National Cancer Institute, Frederick, MD 21702
| | - Aurelie Niyongabo
- HIV Dynamics and Replication Program, National Cancer Institute, Frederick, MD 21702
| | - Adam A Capoferri
- HIV Dynamics and Replication Program, National Cancer Institute, Frederick, MD 21702
| | - Brandon F Keele
- AIDS and Cancer Virus Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702
| | - Jeff Milush
- Department of Medicine, University of California, San Francisco, CA 94143
| | - Rebecca Hoh
- Department of Medicine, University of California, San Francisco, CA 94143
| | - Steven G Deeks
- Department of Medicine, University of California, San Francisco, CA 94143
| | - Frank Maldarelli
- HIV Dynamics and Replication Program, National Cancer Institute, Frederick, MD 21702
| | - Stephen H Hughes
- HIV Dynamics and Replication Program, National Cancer Institute, Frederick, MD 21702
| | - John M Coffin
- Department of Molecular Biology and Microbiology, Tufts University, Boston, MA 02111;
| | - Jason W Rausch
- Basic Research Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702
| | - John W Mellors
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA 15213
| | - Mary F Kearney
- HIV Dynamics and Replication Program, National Cancer Institute, Frederick, MD 21702
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9
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Jayaraman B, Fernandes JD, Yang S, Smith C, Frankel AD. Highly Mutable Linker Regions Regulate HIV-1 Rev Function and Stability. Sci Rep 2019; 9:5139. [PMID: 30914719 PMCID: PMC6435700 DOI: 10.1038/s41598-019-41582-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Accepted: 03/05/2019] [Indexed: 11/12/2022] Open
Abstract
HIV-1 Rev is an essential viral regulatory protein that facilitates the nuclear export of intron-containing viral mRNAs. It is organized into structured, functionally well-characterized motifs joined by less understood linker regions. Our recent competitive deep mutational scanning study confirmed many known constraints in Rev’s established motifs, but also identified positions of mutational plasticity, most notably in surrounding linker regions. Here, we probe the mutational limits of these linkers by testing the activities of multiple truncation and mass substitution mutations. We find that these regions possess previously unknown structural, functional or regulatory roles, not apparent from systematic point mutational approaches. Specifically, the N- and C-termini of Rev contribute to protein stability; mutations in a turn that connects the two main helices of Rev have different effects in different contexts; and a linker region which connects the second helix of Rev to its nuclear export sequence has structural requirements for function. Thus, Rev function extends beyond its characterized motifs, and is tuned by determinants within seemingly plastic portions of its sequence. Additionally, Rev’s ability to tolerate many of these massive truncations and substitutions illustrates the overall mutational and functional robustness inherent in this viral protein.
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Affiliation(s)
- Bhargavi Jayaraman
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, CA, 94158, USA
| | - Jason D Fernandes
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, CA, 94158, USA.,UCSC Genomics Institute/Howard Hughes Medical Institute, University of Santa Cruz, Santa Cruz, CA, 95060, USA
| | - Shumin Yang
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, CA, 94158, USA.,School of Medicine, Tsinghua University, Beijing, 100084, China
| | - Cynthia Smith
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, CA, 94158, USA
| | - Alan D Frankel
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, CA, 94158, USA.
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10
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Watts NR, Eren E, Zhuang X, Wang YX, Steven AC, Wingfield PT. A new HIV-1 Rev structure optimizes interaction with target RNA (RRE) for nuclear export. J Struct Biol 2018; 203:102-108. [PMID: 29605570 DOI: 10.1016/j.jsb.2018.03.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Revised: 03/27/2018] [Accepted: 03/28/2018] [Indexed: 02/06/2023]
Abstract
HIV-1 Rev mediates the nuclear export of unspliced and partially-spliced viral transcripts for the production of progeny genomes and structural proteins. In this process, four (or more) copies of Rev assemble onto a highly-structured 351-nt region in such viral transcripts, the Rev response element (RRE). How this occurs is not known. The Rev assembly domain has a helical-hairpin structure which associates through three (A-A, B-B and C-C) interfaces. The RRE has the topology of an upper-case letter A, with the two known Rev binding sites mapping onto the legs of the A. We have determined a crystal structure for the Rev assembly domain at 2.25 Å resolution, without resort to either mutations or chaperones. It shows that B-B dimers adopt an arrangement reversed relative to that previously reported, and join through a C-C interface to form tetramers. The new subunit arrangement shows how four Rev molecules can assemble on the two sites on the RRE to form the specificity checkpoint, and how further copies add through A-A interactions. Residues at the C-C interface, specifically the Pro31-Trp45 axis, are a potential target for intervention.
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Affiliation(s)
- Norman R Watts
- Protein Expression Laboratory, NIAMS, NIH, Bethesda, MD 20892, USA
| | - Elif Eren
- Laboratory of Structural Biology Research, NIAMS, NIH, Bethesda, MD 20892, USA
| | - Xiaolei Zhuang
- Protein Expression Laboratory, NIAMS, NIH, Bethesda, MD 20892, USA
| | - Yun-Xing Wang
- Structural Biophysics Laboratory, NCI, NIH, Frederick, MD 21702, USA
| | - Alasdair C Steven
- Laboratory of Structural Biology Research, NIAMS, NIH, Bethesda, MD 20892, USA
| | - Paul T Wingfield
- Protein Expression Laboratory, NIAMS, NIH, Bethesda, MD 20892, USA.
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