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Heng X, Herrera AP, Song Z, Boris-Lawrie K. Retroviral PBS-segment sequence and structure: Orchestrating early and late replication events. Retrovirology 2024; 21:12. [PMID: 38886829 PMCID: PMC11181671 DOI: 10.1186/s12977-024-00646-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Accepted: 06/06/2024] [Indexed: 06/20/2024] Open
Abstract
An essential regulatory hub for retroviral replication events, the 5' untranslated region (UTR) encodes an ensemble of cis-acting replication elements that overlap in a logical manner to carry out divergent RNA activities in cells and in virions. The primer binding site (PBS) and primer activation sequence initiate the reverse transcription process in virions, yet overlap with structural elements that regulate expression of the complex viral proteome. PBS-segment also encompasses the attachment site for Integrase to cut and paste the 3' long terminal repeat into the host chromosome to form the provirus and purine residues necessary to execute the precise stoichiometry of genome-length transcripts and spliced viral RNAs. Recent genetic mapping, cofactor affinity experiments, NMR and SAXS have elucidated that the HIV-1 PBS-segment folds into a three-way junction structure. The three-way junction structure is recognized by the host's nuclear RNA helicase A/DHX9 (RHA). RHA tethers host trimethyl guanosine synthase 1 to the Rev/Rev responsive element (RRE)-containing RNAs for m7-guanosine Cap hyper methylation that bolsters virion infectivity significantly. The HIV-1 trimethylated (TMG) Cap licenses specialized translation of virion proteins under conditions that repress translation of the regulatory proteins. Clearly host-adaption and RNA shapeshifting comprise the fundamental basis for PBS-segment orchestrating both reverse transcription of virion RNA and the nuclear modification of m7G-Cap for biphasic translation of the complex viral proteome. These recent observations, which have exposed even greater complexity of retroviral RNA biology than previously established, are the impetus for this article. Basic research to fully comprehend the marriage of PBS-segment structures and host RNA binding proteins that carry out retroviral early and late replication events is likely to expose an immutable virus-specific therapeutic target to attenuate retrovirus proliferation.
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Affiliation(s)
- Xiao Heng
- Department of Biochemistry, University of Missouri, Columbia, MO, 65211, USA.
| | - Amanda Paz Herrera
- Department of Biochemistry, University of Missouri, Columbia, MO, 65211, USA
| | - Zhenwei Song
- Department of Veterinary and Biomedical Sciences, Institute for Molecular Virology, University of Minnesota, Saint Paul, MN, 55108, USA
| | - Kathleen Boris-Lawrie
- Department of Veterinary and Biomedical Sciences, Institute for Molecular Virology, University of Minnesota, Saint Paul, MN, 55108, USA.
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Kishimoto N, Misumi S. From Glycolysis to Viral Defense: The Multifaceted Impact of Glycolytic Enzymes on Human Immunodeficiency Virus Type 1 Replication. Biol Pharm Bull 2024; 47:905-911. [PMID: 38692867 DOI: 10.1248/bpb.b23-00605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2024]
Abstract
Viruses require host cells to replicate and proliferate, which indicates that viruses hijack the cellular machinery. Human immunodeficiency virus type 1 (HIV-1) primarily infects CD4-positive T cells, and efficiently uses cellular proteins to replicate. Cells already have proteins that inhibit the replication of the foreign HIV-1, but their function is suppressed by viral proteins. Intriguingly, HIV-1 infection also changes the cellular metabolism to aerobic glycolysis. This phenomenon has been interpreted as a cellular response to maintain homeostasis during viral infection, yet HIV-1 efficiently replicates even in this environment. In this review, we discuss the regulatory role of glycolytic enzymes in viral replication and the impact of aerobic glycolysis on viral infection by introducing various host proteins involved in viral replication. Furthermore, we would like to propose a "glyceraldehyde-3-phosphate dehydrogenase-induced shock (G-shock) and kill strategy" that maximizes the antiviral effect of the glycolytic enzyme glyceraldehyde 3-phosphate dehydrogenase (GAPDH) to eliminate latently HIV-1-infected cells.
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Affiliation(s)
- Naoki Kishimoto
- Department of Environmental and Molecular Health Sciences, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University
| | - Shogo Misumi
- Department of Environmental and Molecular Health Sciences, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University
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3
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Inadvertent Transfer of Murine VL30 Retrotransposons to CAR-T Cells. ADVANCES IN CELL AND GENE THERAPY 2022; 2022. [PMID: 36081760 PMCID: PMC9450689 DOI: 10.1155/2022/6435077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
For more than a decade, genetically engineered autologous T-cells have been successfully employed as immunotherapy drugs for patients with incurable blood cancers. The active components in some of these game-changing medicines are autologous T-cells that express viral vector-delivered chimeric antigen receptors (CARs), which specifically target proteins that are preferentially expressed on cancer cells. Some of these therapeutic CAR expressing T-cells (CAR-Ts) are engineered via transduction with
-retroviral vectors (
-RVVs) produced in a stable producer cell line that was derived from murine PG13 packaging cells (ATCC CRL-10686). Earlier studies reported on the copackaging of murine virus-like 30S RNA (VL30) genomes with
-retroviral vectors generated in murine stable packaging cells. In an earlier study, VL30 mRNA was found to enhance the metastatic potential of human melanoma cells. These findings raise biosafety concerns regarding the possibility that therapeutic CAR-Ts have been inadvertently contaminated with potentially oncogenic VL30 retrotransposons. In this study, we demonstrated the presence of infectious VL30 particles in PG13 cell-conditioned media and observed the ability of these particles to deliver transcriptionally active VL30 genomes to human cells. Notably, VL30 genomes packaged by HIV-1-based vector particles transduced naïve human cells in culture. Furthermore, we detected the transfer and expression of VL30 genomes in clinical-grade CAR-T cells generated by transduction with PG13 cell-derived
-retroviral vectors. Our findings raise biosafety concerns regarding the use of murine packaging cell lines in ongoing clinical applications.
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Species-specific KRAB-ZFPs function as repressors of retroviruses by targeting PBS regions. Proc Natl Acad Sci U S A 2022; 119:e2119415119. [PMID: 35259018 PMCID: PMC8931336 DOI: 10.1073/pnas.2119415119] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Hosts often target the relatively conserved regions in rapidly mutating retroviruses to inhibit their replication. One of these regions is called a primer binding site (PBS), which has to be complementary to the host tRNA to initiate reverse transcription. By analyzing endogenous retroviral elements, we found that host cells use this sequence as a target in efforts to block the expression of viral elements. A specific type of zinc finger protein targets the PBS in a host genome, which not only inhibits the transcription of endogenous viruses but also inhibits the replication of exogenous retroviruses with the same PBS. Thus, our study sheds light on a strategy for searching for host restriction factors targeting retroviruses. Eukaryotic genomes harbor sequences derived from the chromosomal integration of ancient viruses, such as endogenous retroviruses (ERVs), which comprise 8% of the human genome. Like exogenous retroviruses, ERVs retain many common functional elements, including the corresponding DNA sequences of transfer RNA (tRNA) primer binding sites (PBSs), which are utilized for reverse transcription initiation by exogenous retroviruses. Here, through a medium-scale analysis of PBS loci positioned within ERVs, coupled with chromatin immunoprecipitation sequencing (ChIP-seq) of Kruppel-associated box zinc finger proteins (KRAB-ZFPs), we identified multiple ZFPs that specifically bind to different PBS loci. Among these, we focused on PBS-Lys, which is utilized by HIV-1, and identified its specific binding proteins to be mouse ZFP961 and human ZNF417/ZNF587. We found that these proteins not only repress ERV transcription but also inhibit retrovirus integration and transcription. Disruption of these ZFPs rendered cells more susceptible to HIV-1 infection. Thus, our research provides a methodology for identifying potential host factors that target retroviruses by ERVs.
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Cao C, Cai Z, Xiao X, Rao J, Chen J, Hu N, Yang M, Xing X, Wang Y, Li M, Zhou B, Wang X, Wang J, Xue Y. The architecture of the SARS-CoV-2 RNA genome inside virion. Nat Commun 2021; 12:3917. [PMID: 34168138 PMCID: PMC8225788 DOI: 10.1038/s41467-021-22785-x] [Citation(s) in RCA: 114] [Impact Index Per Article: 38.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2020] [Accepted: 03/30/2021] [Indexed: 02/08/2023] Open
Abstract
SARS-CoV-2 carries the largest single-stranded RNA genome and is the causal pathogen of the ongoing COVID-19 pandemic. How the SARS-CoV-2 RNA genome is folded in the virion remains unknown. To fill the knowledge gap and facilitate structure-based drug development, we develop a virion RNA in situ conformation sequencing technology, named vRIC-seq, for probing viral RNA genome structure unbiasedly. Using vRIC-seq data, we reconstruct the tertiary structure of the SARS-CoV-2 genome and reveal a surprisingly "unentangled globule" conformation. We uncover many long-range duplexes and higher-order junctions, both of which are under purifying selections and contribute to the sequential package of the SARS-CoV-2 genome. Unexpectedly, the D614G and the other two accompanying mutations may remodel duplexes into more stable forms. Lastly, the structure-guided design of potent small interfering RNAs can obliterate the SARS-CoV-2 in Vero cells. Overall, our work provides a framework for studying the genome structure, function, and dynamics of emerging deadly RNA viruses.
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Affiliation(s)
- Changchang Cao
- Key Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Zhaokui Cai
- Key Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Xia Xiao
- National Health Commission of the People's Republic of China Key Laboratory of Systems Biology of Pathogens and Christophe Mérieux Laboratory, Institute of Pathogen Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Jian Rao
- National Health Commission of the People's Republic of China Key Laboratory of Systems Biology of Pathogens and Christophe Mérieux Laboratory, Institute of Pathogen Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Juan Chen
- Key Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Naijing Hu
- Key Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Minnan Yang
- CAS Key Laboratory of Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Xiaorui Xing
- CAS Key Laboratory of Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Yongle Wang
- CAS Key Laboratory of Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Manman Li
- School of Life Sciences, Henan Normal University, Xinxiang, China
| | - Bing Zhou
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing, China
| | - Xiangxi Wang
- CAS Key Laboratory of Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Jianwei Wang
- National Health Commission of the People's Republic of China Key Laboratory of Systems Biology of Pathogens and Christophe Mérieux Laboratory, Institute of Pathogen Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China.
- Key Laboratory of Respiratory Disease Pathogenomics, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
| | - Yuanchao Xue
- Key Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.
- University of Chinese Academy of Sciences, Beijing, China.
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Gremminger T, Song Z, Ji J, Foster A, Weng K, Heng X. Extended Interactions between HIV-1 Viral RNA and tRNA Lys3 Are Important to Maintain Viral RNA Integrity. Int J Mol Sci 2020; 22:ijms22010058. [PMID: 33374603 PMCID: PMC7793103 DOI: 10.3390/ijms22010058] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 12/09/2020] [Accepted: 12/19/2020] [Indexed: 01/19/2023] Open
Abstract
The reverse transcription of the human immunodeficiency virus 1 (HIV-1) initiates upon annealing of the 3′-18-nt of tRNALys3 onto the primer binding site (PBS) in viral RNA (vRNA). Additional intermolecular interactions between tRNALys3 and vRNA have been reported, but their functions remain unclear. Here, we show that abolishing one potential interaction, the A-rich loop: tRNALys3 anticodon interaction in the HIV-1 MAL strain, led to a decrease in viral infectivity and reduced the synthesis of reverse transcription products in newly infected cells. In vitro biophysical and functional experiments revealed that disruption of the extended interaction resulted in an increased affinity for reverse transcriptase (RT) and enhanced primer extension efficiency. In the absence of deoxyribose nucleoside triphosphates (dNTPs), vRNA was degraded by the RNaseH activity of RT, and the degradation rate was slower in the complex with the extended interaction. Consistently, the loss of vRNA integrity was detected in virions containing A-rich loop mutations. Similar results were observed in the HIV-1 NL4.3 strain, and we show that the nucleocapsid (NC) protein is necessary to promote the extended vRNA: tRNALys3 interactions in vitro. In summary, our data revealed that the additional intermolecular interaction between tRNALys3 and vRNA is likely a conserved mechanism among various HIV-1 strains and protects the vRNA from RNaseH degradation in mature virions.
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Krupkin M, Jackson LN, Ha B, Puglisi EV. Advances in understanding the initiation of HIV-1 reverse transcription. Curr Opin Struct Biol 2020; 65:175-183. [PMID: 32916568 PMCID: PMC9973426 DOI: 10.1016/j.sbi.2020.07.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 07/12/2020] [Accepted: 07/21/2020] [Indexed: 01/18/2023]
Abstract
Many viruses, including Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) and Human Immunodeficiency Virus (HIV), use RNA as their genetic material. How viruses harness RNA structure and RNA-protein interactions to control their replication remains obscure. Recent advances in the characterization of HIV-1 reverse transcriptase, the enzyme that converts its single-stranded RNA genome into a double-stranded DNA copy, reveal how the reverse transcription complex evolves during initiation. Here we highlight these advances in HIV-1 structural biology and discuss how they are furthering our understanding of HIV and related ribonucleoprotein complexes implicated in viral disease.
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Affiliation(s)
- Miri Krupkin
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Lynnette Nthenya Jackson
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Betty Ha
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA,Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Elisabetta Viani Puglisi
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA.
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Fennessey CM, Camus C, Immonen TT, Reid C, Maldarelli F, Lifson JD, Keele BF. Low-level alternative tRNA priming of reverse transcription of HIV-1 and SIV in vivo. Retrovirology 2019; 16:11. [PMID: 30947720 PMCID: PMC6450007 DOI: 10.1186/s12977-019-0473-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Accepted: 04/01/2019] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND Reverse transcription (RT) of HIV and SIV is initiated by the binding of the acceptor stem of tRNALys3 to the primer binding site (PBS) of the viral RNA genome. Previous studies have suggested that this tRNALys3 is not the only molecule capable of priming reverse transcription, and that at least one other lysyl tRNA, tRNALys5, which has an acceptor stem sequence varying from tRNALys3 by only a single transition mutation resulting in the integration of a thymine (T) at position 8 of the PBS in the viral genome, can prime reverse transcription. RESULTS We undertook an unbiased approach, evaluating the primer binding site by deep-sequencing of HIV and SIV directly from the plasma of 15 humans and 11 macaques. We found that in humans there are low but measurable levels of viral RNA genomes harboring a PBS containing the noncanonical T at position 8 (PBS-Lys5) corresponding to the tRNAlys5 sequence and representing an average of 0.52% (range 0.07-1.6%) of the total viral population. This value is remarkably consistent with the proportion of PBS-Lys5 we identified in a cross-sectional assessment of the LANL HIV database (0.51%). In macaques chronically infected with SIVmac239, the PBS-Lys5 was also detected but at a frequency 1-log less than seen for HIV, with an average of 0.056% (range 0.01-0.09%). At this proportion, PBS-Lys5 was comparable to other transition mutations, making it impossible to determine whether the mutation observed is a result of use of tRNALys5 as an RT primer at very low levels or merely the product of in vitro cDNA synthesis/PCR error. We also identified two novel PBS sequences in HIV and SIV at low levels in vivo corresponding to tRNALys6 and tRNALys1,2, suggesting that these tRNAs may rarely also be used to prime RT. In vivo reversion of the PBS-Lys5 found in SIVmac239 was rapid and reached background levels by 30 days post-infection. CONCLUSIONS We conclude that while alternative tRNAs can initiate reverse transcription of HIV and SIV in vivo, their overall contributions to the replicating viral population are small.
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Affiliation(s)
- Christine M. Fennessey
- AIDS and Cancer Virus Program, Frederick National Laboratory for Cancer Research, Frederick, MD 21702 USA
| | - Celine Camus
- AIDS and Cancer Virus Program, Frederick National Laboratory for Cancer Research, Frederick, MD 21702 USA
| | - Taina T. Immonen
- AIDS and Cancer Virus Program, Frederick National Laboratory for Cancer Research, Frederick, MD 21702 USA
| | - Carolyn Reid
- AIDS and Cancer Virus Program, Frederick National Laboratory for Cancer Research, Frederick, MD 21702 USA
| | - Frank Maldarelli
- HIV Dynamics and Replication Program, National Cancer Institute, Frederick, MD 21702 USA
| | - Jeffrey D. Lifson
- AIDS and Cancer Virus Program, Frederick National Laboratory for Cancer Research, Frederick, MD 21702 USA
| | - Brandon F. Keele
- AIDS and Cancer Virus Program, Frederick National Laboratory for Cancer Research, Frederick, MD 21702 USA
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Jin D, Musier-Forsyth K. Role of host tRNAs and aminoacyl-tRNA synthetases in retroviral replication. J Biol Chem 2019; 294:5352-5364. [PMID: 30700559 DOI: 10.1074/jbc.rev118.002957] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The lifecycle of retroviruses and retrotransposons includes a reverse transcription step, wherein dsDNA is synthesized from genomic RNA for subsequent insertion into the host genome. Retroviruses and retrotransposons commonly appropriate major components of the host cell translational machinery, including cellular tRNAs, which are exploited as reverse transcription primers. Nonpriming functions of tRNAs have also been proposed, such as in HIV-1 virion assembly, and tRNA-derived fragments may also be involved in retrovirus and retrotransposon replication. Moreover, host cellular proteins regulate retroviral replication by binding to tRNAs and thereby affecting various steps in the viral lifecycle. For example, in some cases, tRNA primer selection is facilitated by cognate aminoacyl-tRNA synthetases (ARSs), which bind tRNAs and ligate them to their corresponding amino acids, but also have many known nontranslational functions. Multi-omic studies have revealed that ARSs interact with both viral proteins and RNAs and potentially regulate retroviral replication. Here, we review the currently known roles of tRNAs and their derivatives in retroviral and retrotransposon replication and shed light on the roles of tRNA-binding proteins such as ARSs in this process.
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Affiliation(s)
- Danni Jin
- From the Department of Chemistry and Biochemistry, Center for Retrovirus Research, and Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210
| | - Karin Musier-Forsyth
- From the Department of Chemistry and Biochemistry, Center for Retrovirus Research, and Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210
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Wang Z, Wang W, Cui YC, Pan Q, Zhu W, Gendron P, Guo F, Cen S, Witcher M, Liang C. HIV-1 Employs Multiple Mechanisms To Resist Cas9/Single Guide RNA Targeting the Viral Primer Binding Site. J Virol 2018; 92:e01135-18. [PMID: 30068653 PMCID: PMC6158435 DOI: 10.1128/jvi.01135-18] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 07/26/2018] [Indexed: 12/23/2022] Open
Abstract
The clustered regularly interspaced short palindromic repeat (CRISPR)-CRISPR-associated protein 9 (Cas9) gene-editing technology has been used to inactivate viral DNA as a new strategy to eliminate chronic viral infections, including HIV-1. This utility of CRISPR-Cas9 is challenged by the high heterogeneity of HIV-1 sequences, which requires the design of the single guide RNA (sgRNA; utilized by the CRISPR-Cas9 system to recognize the target DNA) to match a specific HIV-1 strain in an HIV patient. One solution to this challenge is to target the viral primer binding site (PBS), which HIV-1 copies from cellular tRNA3 Lys in each round of reverse transcription and is thus conserved in almost all HIV-1 strains. In this study, we demonstrate that PBS-targeting sgRNA directs Cas9 to cleave the PBS DNA, which evokes deletions or insertions (indels) and strongly diminishes the production of infectious HIV-1. While HIV-1 escapes from PBS-targeting Cas9/sgRNA, unique resistance mechanisms are observed that are dependent on whether the plus or the minus strand of the PBS DNA is bound by sgRNA. Characterization of these viral escape mechanisms will inform future engineering of Cas9 variants that can more potently and persistently inhibit HIV-1 infection.IMPORTANCE The results of this study demonstrate that the gene-editing complex Cas9/sgRNA can be programmed to target and cleave HIV-1 PBS DNA, and thus, inhibit HIV-1 infection. Given that almost all HIV-1 strains have the same PBS, which is copied from the cellular tRNA3 Lys during reverse transcription, PBS-targeting sgRNA can be used to inactivate HIV-1 DNA of different strains. We also discovered that HIV-1 uses different mechanisms to resist Cas9/sgRNAs, depending on whether they target the plus or the minus strand of PBS DNA. These findings allow us to predict that a Cas9 variant that uses the CCA sequence as the protospacer adjacent motif (PAM) should more strongly and persistently suppress HIV-1 replication. Together, these data have identified the PBS as the target DNA of Cas9/sgRNA and have predicted how to improve Cas9/sgRNA to achieve more efficient and sustainable suppression of HIV-1 infection, therefore improving the capacity of Cas9/sgRNA in curing HIV-1 infection.
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Affiliation(s)
- Zhen Wang
- Lady Davis Institute, Jewish General Hospital, Montreal, Canada
- Department of Medicine, McGill University, Montreal, Canada
| | - Wenzhou Wang
- Lady Davis Institute, Jewish General Hospital, Montreal, Canada
- Department of Microbiology & Immunology, McGill University, Montreal, Canada
| | - Ya Cheng Cui
- Department of Medicine, McGill University, Montreal, Canada
| | - Qinghua Pan
- Lady Davis Institute, Jewish General Hospital, Montreal, Canada
| | - Weijun Zhu
- Institute of Pathogen Biology, Chinese Academy of Medical Science, Beijing, China
| | - Patrick Gendron
- Institute for Research in Immunology and Cancer, University of Montreal, Montreal, Canada
| | - Fei Guo
- Institute of Pathogen Biology, Chinese Academy of Medical Science, Beijing, China
| | - Shan Cen
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Science, Beijing, China
| | - Michael Witcher
- Lady Davis Institute, Jewish General Hospital, Montreal, Canada
- Department of Oncology, McGill University, Montreal, Canada
| | - Chen Liang
- Lady Davis Institute, Jewish General Hospital, Montreal, Canada
- Department of Medicine, McGill University, Montreal, Canada
- Department of Microbiology & Immunology, McGill University, Montreal, Canada
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11
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Noncoding RNAs in Retrovirus Replication. RETROVIRUS-CELL INTERACTIONS 2018. [PMCID: PMC7173536 DOI: 10.1016/b978-0-12-811185-7.00012-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Although a limited percentage of the genome produces proteins, approximately 90% is transcribed, indicating important roles for noncoding RNA (ncRNA). It is now known that these ncRNAs have a multitude of cellular functions ranging from the regulation of gene expression to roles as structural elements in ribonucleoprotein complexes. ncRNA is also represented at nearly every step of viral life cycles. This chapter will focus on ncRNAs of both host and viral origin and their roles in retroviral life cycles. Cellular ncRNA represents a significant portion of material packaged into retroviral virions and includes transfer RNAs, 7SL RNA, U RNA, and vault RNA. Initially thought to be random packaging events, these host RNAs are now proposed to contribute to viral assembly and infectivity. Within the cell, long ncRNA and endogenous retroviruses have been found to regulate aspects of the retroviral life cycle in diverse ways. Additionally, the HIV-1 transactivating response element RNA is thought to impact viral infection beyond the well-characterized role as a transcription activator. RNA interference, thought to be an early version of the innate immune response to viral infection, can still be observed in plants and invertebrates today. The ability of retroviral infection to manipulate the host RNAi pathway is described here. Finally, RNA-based therapies, including gene editing approaches, are being explored as antiretroviral treatments and are discussed.
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12
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Sampathkumar R, Scott-Herridge J, Liang B, Kimani J, Plummer FA, Luo M. HIV-1 Subtypes and 5'LTR-Leader Sequence Variants Correlate with Seroconversion Status in Pumwani Sex Worker Cohort. Viruses 2017; 10:v10010004. [PMID: 29295533 PMCID: PMC5795417 DOI: 10.3390/v10010004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Revised: 12/18/2017] [Accepted: 12/20/2017] [Indexed: 01/04/2023] Open
Abstract
Within the Pumwani sex worker cohort, a subgroup remains seronegative, despite frequent exposure to HIV-1; some of them seroconverted several years later. This study attempts to identify viral variations in 5′LTR-leader sequences (5′LTR-LS) that might contribute to the late seroconversion. The 5′LTR-LS contains sites essential for replication and genome packaging, viz, primer binding site (PBS), major splice donor (SD), and major packaging signal (PS). The 5′LTR-LS of 20 late seroconverters (LSC) and 122 early seroconverters (EC) were amplified, cloned, and sequenced. HelixTree 6.4.3 was employed to classify HIV subtypes and sequence variants based on seroconversion status. We find that HIV-1 subtypes A1.UG and D.UG were overrepresented in the viruses infecting the LSC (P < 0.0001). Specific variants of PBS (Pc < 0.0001), SD1 (Pc < 0.0001), and PS (Pc < 0.0001) were present only in the viral population from EC or LSC. Combinations of PBS [PBS-2 (Pc < 0.0001) and PBS-3 (Pc < 0.0001)] variants with specific SD sequences were only seen in LSC or EC. Combinations of A1.KE or D with specific PBS and SD variants were only present in LSC or EC (Pc < 0.0001). Furthermore, PBS variants only present in LSC co-clustered with PBS references utilizing tRNAArg; whereas, the PBS variants identified only in EC co-clustered with PBS references using tRNALys,3 and its variants. This is the first report that specific PBS, SD1, and PS sequence variants within 5′LTR-LS are associated with HIV-1 seroconversion, and it could aid designing effective anti-HIV strategies.
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Affiliation(s)
- Raghavan Sampathkumar
- Department of Medical Microbiology, University of Manitoba, Winnipeg, MB, R3E 0J9, Canada.
- National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, MB, R3E 3R2, Canada.
| | - Joel Scott-Herridge
- National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, MB, R3E 3R2, Canada.
| | - Binhua Liang
- National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, MB, R3E 3R2, Canada.
- Department of Biochemistry and Medical Genetics, University of Manitoba, Winnipeg, MB, R3E 0J9, Canada.
| | - Joshua Kimani
- Department of Medical Microbiology, University of Manitoba, Winnipeg, MB, R3E 0J9, Canada.
- Department of Medical Microbiology, University of Nairobi, Nairobi, Kenya.
| | - Francis A Plummer
- Department of Medical Microbiology, University of Manitoba, Winnipeg, MB, R3E 0J9, Canada.
- National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, MB, R3E 3R2, Canada.
| | - Ma Luo
- Department of Medical Microbiology, University of Manitoba, Winnipeg, MB, R3E 0J9, Canada.
- National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, MB, R3E 3R2, Canada.
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13
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It Is Imperative to Establish a Pellucid Definition of Chimeric RNA and to Clear Up a Lot of Confusion in the Relevant Research. Int J Mol Sci 2017; 18:ijms18040714. [PMID: 28350330 PMCID: PMC5412300 DOI: 10.3390/ijms18040714] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 03/15/2017] [Accepted: 03/17/2017] [Indexed: 12/27/2022] Open
Abstract
There have been tens of thousands of RNAs deposited in different databases that contain sequences of two genes and are coined chimeric RNAs, or chimeras. However, "chimeric RNA" has never been lucidly defined, partly because "gene" itself is still ill-defined and because the means of production for many RNAs is unclear. Since the number of putative chimeras is soaring, it is imperative to establish a pellucid definition for it, in order to differentiate chimeras from regular RNAs. Otherwise, not only will chimeric RNA studies be misled but also characterization of fusion genes and unannotated genes will be hindered. We propose that only those RNAs that are formed by joining two RNA transcripts together without a fusion gene as a genomic basis should be regarded as authentic chimeras, whereas those RNAs transcribed as, and cis-spliced from, single transcripts should not be deemed as chimeras. Many RNAs containing sequences of two neighboring genes may be transcribed via a readthrough mechanism, and thus are actually RNAs of unannotated genes or RNA variants of known genes, but not chimeras. In today's chimeric RNA research, there are still several key flaws, technical constraints and understudied tasks, which are also described in this perspective essay.
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Berkhout B, Das AT. On the primer binding site mutation that appears and disappears during HIV and SIV replication. Retrovirology 2015; 12:75. [PMID: 26303815 PMCID: PMC4549124 DOI: 10.1186/s12977-015-0201-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Accepted: 08/19/2015] [Indexed: 11/10/2022] Open
Abstract
A recent study by Fennessey et al. (Retrovirology 12:49, 2015) described the optimization of a popular SIV clone by removal of four suboptimal point mutations. One of these mutations is present in a non-coding part of the viral genome and is probed in that study in more detail because of some fascinating properties. This primer binding site (PBS) mutation reverts rapidly to the wild-type sequence, which the authors interpret as indicating that this mutation exerts a profound fitness impact. The authors proposed the involvement of a cellular DNA repair mechanism in the reversion. Furthermore, it was suggested that premature termination of reverse transcription can explain why some of the viral progeny still contained the mutant sequence. However, we argue that all these special properties are a direct consequence of the unique nature of the viral PBS motif. The PBS binds the tRNA primer for reverse transcription and the viral progeny inherits either the sequence of the cellular tRNA or the PBS sequence of the viral RNA genome. The presence of a variant tRNA species explains the rapid appearance and disappearance of a variant PBS sequence.
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Affiliation(s)
- Ben Berkhout
- Department of Medical Microbiology, Laboratory of Experimental Virology, Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, University of Amsterdam, Meibergdreef 15, 1105 AZ, Amsterdam, The Netherlands.
| | - Atze T Das
- Department of Medical Microbiology, Laboratory of Experimental Virology, Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, University of Amsterdam, Meibergdreef 15, 1105 AZ, Amsterdam, The Netherlands.
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15
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Seif E, Niu M, Kleiman L. In virio SHAPE analysis of tRNA(Lys3) annealing to HIV-1 genomic RNA in wild type and protease-deficient virus. Retrovirology 2015; 12:40. [PMID: 25981241 PMCID: PMC4445796 DOI: 10.1186/s12977-015-0171-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Accepted: 05/06/2015] [Indexed: 11/29/2022] Open
Abstract
Background tRNALys3 annealing to the viral RNA of human immunodeficiency virus type-1 (HIV-1) is an essential step in the virus life cycle, because this tRNA serves as the primer for initiating reverse transcription. tRNALys3 annealing to viral RNA occurs in two steps. First, Gag promotes annealing of tRNALys3 to the viral RNA during cytoplasmic HIV-1 assembly. Second, mature nucleocapsid (NCp7), produced from the processing of Gag by viral protease during viral budding from the cell, remodels the annealed complex to form a more stable interaction between the viral RNA and tRNALys3, resulting in a more tightly bound and efficient primer for reverse transcription. Results In this report, we have used in virio SHAPE analysis of both the 5´-untranslated region in HIV-1 RNA and the annealed tRNALys3 to determine structural differences of the annealed complex that occur between protease-negative (Pr-) and wild type viruses. Our results indicate that the weaker binding of tRNALys3 annealed by Gag in Pr- virions reflects both missing interactions of tRNALys3 with viral RNA regions in the upper PBS stem, and a weaker interaction with the internal stem-loop found within the unannealed primer binding site in viral RNA. Conclusions We propose secondary structure models for the tRNALys3/viral RNA annealed complexes in PR- and wild type viruses that support the two-step annealing model by showing that Gag promotes a partial annealing of tRNALys3 to HIV-1 viral RNA, followed by a more complete annealing by NCp7. Electronic supplementary material The online version of this article (doi:10.1186/s12977-015-0171-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Elias Seif
- Lady Davis Institute for Medical Research and McGill AIDS Centre, Jewish General Hospital, Montreal, QC, H3T 1E2, Canada.
| | - Meijuan Niu
- Lady Davis Institute for Medical Research and McGill AIDS Centre, Jewish General Hospital, Montreal, QC, H3T 1E2, Canada.
| | - Lawrence Kleiman
- Lady Davis Institute for Medical Research and McGill AIDS Centre, Jewish General Hospital, Montreal, QC, H3T 1E2, Canada. .,Department of Medicine, McGill University, Montreal, QC, H3A 1A1, Canada.
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16
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Wu C, Nerurkar VR, Lu Y. New insights into inhibition of human immunodeficiency virus type 1 replication through mutant tRNALys3. Retrovirology 2013; 10:112. [PMID: 24156557 PMCID: PMC3832253 DOI: 10.1186/1742-4690-10-112] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Accepted: 09/25/2013] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND Host cellular tRNA(Lys3) is exclusively utilized by human immunodeficiency virus type 1 (HIV-1) as a primer for the replication step of reverse transcription (RTion). Consequently, the priming step of HIV-1 RT constitutes a potential target for anti-HIV-1 intervention. Previous studies indicated that a mutant tRNA(Lys3) with 7-nucleotide substitutions in the 3' terminus resulted in aberrant HIV-1 RTion from the trans-activation response region (TAR) and inhibition of HIV-1 replication. However, the mutant tRNA(Lys3) also directed HIV-1 RTion from the normal primer-binding site (PBS) with potentially weakened anti-HIV-1 activity. To achieve improved targeting of HIV-1 RTion at sites not including the PBS, a series of mutant tRNA(Lys3) with extended lengths of mutations containing up to 18 bases complementary to their targeting sites were constructed and characterized. RESULTS A positive correlation between the length of mutation in the 3' PBS-binding region of tRNA(Lys3) and the specificity of HIV-1 RTion initiation from the targeting site was demonstrated, as indicated by the potency of HIV-1 inhibition and results of priming assays. Moreover, two mutant tRNA(Lys3)s that targeted the IN-encoding region and Env gene, respectively, both showed a high anti-HIV-1 activity, suggesting that not only the TAR, but also distant sites downstream of the PBS could be effectively targeted by mutant tRNA(Lys3). To increase the expression of mutant tRNA(Lys3), multiple-copy expression cassettes were introduced into target cells with increased anti-HIV-1 potency. CONCLUSIONS These results highlight the importance of the length of complementarity between the 3' terminus of the mutant tRNA(Lys3) and its target site, and the feasibility of targeting multiple sites within the HIV-1 genome through mutant tRNA(Lys3). Intervention of the HIV-1 genome conversion through mutant tRNA(Lys3) may constitute an effective approach for development of novel therapeutics against HIV-1 replication and HIV-1-associated diseases.
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Affiliation(s)
- Chengxiang Wu
- Department of Public Health Sciences, John A. Burns School of Medicine, University of Hawaii at Manoa, 1960 East–west Road, Biomed. Bldg, D105, Honolulu, Hawaii 96822, USA
- Department of Microbiology, College of Natural Sciences, University of Hawaii at Manoa, 2538 McCarthy Mall, Snyder 207, Honolulu, HI 96822, USA
| | - Vivek R Nerurkar
- Departments of Tropical Medicine, Medical Microbiology and Pharmacology, Asia-Pacific Institute of Tropical Medicine and Infectious Diseases. John A. Burns School of Medicine, University of Hawaii at Manoa, 651 Ilalo Street, BSB 325AA, Honolulu, HI 96813, USA
| | - Yuanan Lu
- Department of Public Health Sciences, John A. Burns School of Medicine, University of Hawaii at Manoa, 1960 East–west Road, Biomed. Bldg, D105, Honolulu, Hawaii 96822, USA
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17
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Sleiman D, Barraud P, Brachet F, Tisne C. The Interaction between tRNA(Lys) 3 and the primer activation signal deciphered by NMR spectroscopy. PLoS One 2013; 8:e64700. [PMID: 23762248 PMCID: PMC3675109 DOI: 10.1371/journal.pone.0064700] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Accepted: 04/17/2013] [Indexed: 11/23/2022] Open
Abstract
The initiation of reverse transcription of the human immunodeficiency virus type 1 (HIV-1) requires the opening of the three-dimensional structure of the primer tRNALys3 for its annealing to the viral RNA at the primer binding site (PBS). Despite the fact that the result of this rearrangement is thermodynamically more stable, there is a high-energy barrier that requires the chaperoning activity of the viral nucleocapsid protein. In addition to the nucleotide complementarity to the PBS, several regions of tRNALys3 have been described as interacting with the viral genomic RNA. Among these sequences, a sequence of the viral genome called PAS for “primer activation signal” was proposed to interact with the T-arm of tRNALys3, this interaction stimulating the initiation of reverse transcription. In this report, we investigate the formation of this additional interaction with NMR spectroscopy, using a simple system composed of the primer tRNALys3, the 18 nucleotides of the PBS, the PAS (8 nucleotides) encompassed or not in a hairpin structure, and the nucleocapsid protein. Our NMR study provides molecular evidence of the existence of this interaction and highlights the role of the nucleocapsid protein in promoting this additional RNA-RNA annealing. This study presents the first direct observation at a single base-pair resolution of the PAS/anti-PAS association, which has been proposed to be involved in the chronological regulation of the reverse transcription.
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Affiliation(s)
- Dona Sleiman
- Laboratoire de Cristallographie et RMN biologiques, CNRS, Université Paris Descartes, Paris Sorbonne Cité, Paris, France
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18
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Aspects of HIV-1 assembly that promote primer tRNALys3 annealing to viral RNA. Virus Res 2012; 169:340-8. [DOI: 10.1016/j.virusres.2012.06.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Revised: 05/25/2012] [Accepted: 06/01/2012] [Indexed: 01/30/2023]
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19
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Sleiman D, Goldschmidt V, Barraud P, Marquet R, Paillart JC, Tisné C. Initiation of HIV-1 reverse transcription and functional role of nucleocapsid-mediated tRNA/viral genome interactions. Virus Res 2012; 169:324-39. [PMID: 22721779 DOI: 10.1016/j.virusres.2012.06.006] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Revised: 06/05/2012] [Accepted: 06/06/2012] [Indexed: 12/28/2022]
Abstract
HIV-1 reverse transcription is initiated from a tRNA(Lys)(3) molecule annealed to the viral RNA at the primer binding site (PBS). The annealing of tRNA(Lys)(3) requires the opening of its three-dimensional structure and RNA rearrangements to form an efficient initiation complex recognized by the reverse transcriptase. This annealing is mediated by the nucleocapsid protein (NC). In this paper, we first review the actual knowledge about HIV-1 viral RNA and tRNA(Lys)(3) structures. Then, we summarize the studies explaining how NC chaperones the formation of the tRNA(Lys)(3)/PBS binary complex. Additional NMR data that investigated the NC interaction with tRNA(Lys)(3) D-loop are presented. Lastly, we focused on the additional interactions occurring between tRNA(Lys)(3) and the viral RNA and showed that they are dependent on HIV-1 isolates, i.e. the sequence and the structure of the viral RNA.
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Affiliation(s)
- Dona Sleiman
- Laboratoire de Cristallographie et RMN biologiques, Université Paris-Descartes, CNRS UMR 8015, 4 avenue de l'Observatoire, 75006 Paris, France
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20
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Puglisi EV, Puglisi JD. Secondary structure of the HIV reverse transcription initiation complex by NMR. J Mol Biol 2011; 410:863-74. [PMID: 21763492 DOI: 10.1016/j.jmb.2011.04.024] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2011] [Revised: 04/06/2011] [Accepted: 04/11/2011] [Indexed: 01/11/2023]
Abstract
Initiation of reverse transcription of genomic RNA is a key early step in replication of the human immunodeficiency virus (HIV) upon infection of a host cell. Viral reverse transcriptase initiates from a specific RNA-RNA complex formed between a host transfer RNA (tRNA(Lys)(3)) and a region at the 5' end of genomic RNA; the 3' end of the tRNA acts as a primer for reverse transcription of genomic RNA. We report here the secondary structure of the HIV genomic RNA-human tRNA(Lys)(3) initiation complex using heteronuclear nuclear magnetic resonance methods. We show that both RNAs undergo large-scale conformational changes upon complex formation. Formation of the 18-bp primer helix with the 3' end of tRNA(Lys)(3) drives large conformational rearrangements of the tRNA at the 5' end while maintaining the anticodon loop for potential loop-loop interactions. HIV RNA forms an intramolecular helix adjacent to the intermolecular primer helix. This helix, which must be broken by reverse transcription, likely acts as a kinetic block to reverse transcription.
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Affiliation(s)
- Elisabetta Viani Puglisi
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305-5126, USA.
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21
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Graham WD, Barley-Maloney L, Stark CJ, Kaur A, Stolyarchuk K, Sproat B, Leszczynska G, Malkiewicz A, Safwat N, Mucha P, Guenther R, Agris PF. Functional recognition of the modified human tRNALys3(UUU) anticodon domain by HIV's nucleocapsid protein and a peptide mimic. J Mol Biol 2011; 410:698-715. [PMID: 21762809 PMCID: PMC3662833 DOI: 10.1016/j.jmb.2011.04.025] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2011] [Revised: 04/06/2011] [Accepted: 04/11/2011] [Indexed: 11/27/2022]
Abstract
The HIV-1 nucleocapsid protein, NCp7, facilitates the use of human tRNA(Lys3)(UUU) as the primer for reverse transcription. NCp7 also remodels the htRNA's amino acid accepting stem and anticodon domains in preparation for their being annealed to the viral genome. To understand the possible influence of the htRNA's unique composition of post-transcriptional modifications on NCp7 recognition of htRNA(Lys3)(UUU), the protein's binding and functional remodeling of the human anticodon stem and loop domain (hASL(Lys3)) were studied. NCp7 bound the hASL(Lys3)(UUU) modified with 5-methoxycarbonylmethyl-2-thiouridine at position-34 (mcm(5)s(2)U(34)) and 2-methylthio-N(6)-threonylcarbamoyladenosine at position-37 (ms(2)t(6)A(37)) with a considerably higher affinity than the unmodified hASL(Lys3)(UUU) (K(d)=0.28±0.03 and 2.30±0.62 μM, respectively). NCp7 denatured the structure of the hASL(Lys3)(UUU)-mcm(5)s(2)U(34);ms(2)t(6)A(37);Ψ(39) more effectively than that of the unmodified hASL(Lys3)(UUU). Two 15 amino acid peptides selected from phage display libraries demonstrated a high affinity (average K(d)=0.55±0.10 μM) and specificity for the ASL(Lys3)(UUU)-mcm(5)s(2)U(34);ms(2)t(6)A(37) comparable to that of NCp7. The peptides recognized a t(6)A(37)-modified ASL with an affinity (K(d)=0.60±0.09 μM) comparable to that for hASL(Lys3)(UUU)-mcm(5)s(2)U(34);ms(2)t(6)A(37), indicating a preference for the t(6)A(37) modification. Significantly, one of the peptides was capable of relaxing the hASL(Lys3)(UUU)-mcm(5)s(2)U(34);ms(2)t(6)A(37);Ψ(39) structure in a manner similar to that of NCp7, and therefore could be used to further study protein recognition of RNA modifications. The post-transcriptional modifications of htRNA(Lys3)(UUU) have been found to be important determinants of NCp7's recognition prior to the tRNA(Lys3)(UUU) being annealed to the viral genome as the primer of reverse transcription.
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Affiliation(s)
- William D. Graham
- Molecular and Structural Biochemistry, North Carolina State University, Raleigh NC 27695, USA
| | - Lise Barley-Maloney
- Molecular and Structural Biochemistry, North Carolina State University, Raleigh NC 27695, USA
| | - Caren J. Stark
- Te RNA Institute, Biological Sciences, University at Albany, Albany, NY 12222, USA
| | - Amarpreet Kaur
- Molecular and Structural Biochemistry, North Carolina State University, Raleigh NC 27695, USA
| | - Khrystyna Stolyarchuk
- Molecular and Structural Biochemistry, North Carolina State University, Raleigh NC 27695, USA
| | - Brian Sproat
- Integrated DNA Technologies BVBA, Interleuvenlaan 12A, B-3001 Leuven, Belgium
| | - Grazyna Leszczynska
- Institute of Organic Chemistry, Technical University, Żeromskiego 116, 90-924, ŁódŸ, Poland
| | - Andrzej Malkiewicz
- Institute of Organic Chemistry, Technical University, Żeromskiego 116, 90-924, ŁódŸ, Poland
| | - Nedal Safwat
- Molecular and Structural Biochemistry, North Carolina State University, Raleigh NC 27695, USA
| | - Piotr Mucha
- Department of Chemistry, University of Gdansk, Sobieskiego 18, 80-952 Gdansk, Poland
| | - Richard Guenther
- Molecular and Structural Biochemistry, North Carolina State University, Raleigh NC 27695, USA
| | - Paul F. Agris
- Te RNA Institute, Biological Sciences, University at Albany, Albany, NY 12222, USA
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22
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Isel C, Ehresmann C, Marquet R. Initiation of HIV Reverse Transcription. Viruses 2010; 2:213-243. [PMID: 21994608 PMCID: PMC3185550 DOI: 10.3390/v2010213] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2009] [Revised: 01/08/2010] [Accepted: 01/13/2010] [Indexed: 12/01/2022] Open
Abstract
Reverse transcription of retroviral genomes into double stranded DNA is a key event for viral replication. The very first stage of HIV reverse transcription, the initiation step, involves viral and cellular partners that are selectively packaged into the viral particle, leading to an RNA/protein complex with very specific structural and functional features, some of which being, in the case of HIV-1, linked to particular isolates. Recent understanding of the tight spatio-temporal regulation of reverse transcription and its importance for viral infectivity further points toward reverse transcription and potentially its initiation step as an important drug target.
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Affiliation(s)
- Catherine Isel
- Authors to whom correspondence should be addressed; E-Mail: ; Tel.: +33-388-417-040; Fax: +33-388-602-218 (C.I.); E-Mail: ; Tel.: +33-388-417-054; Fax: +33-388-602-218 (R.M.)
| | | | - Roland Marquet
- Authors to whom correspondence should be addressed; E-Mail: ; Tel.: +33-388-417-040; Fax: +33-388-602-218 (C.I.); E-Mail: ; Tel.: +33-388-417-054; Fax: +33-388-602-218 (R.M.)
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23
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Tuiskunen A, Leparc-Goffart I, Boubis L, Monteil V, Klingström J, Tolou HJ, Lundkvist A, Plumet S. Self-priming of reverse transcriptase impairs strand-specific detection of dengue virus RNA. J Gen Virol 2009; 91:1019-27. [PMID: 19940062 DOI: 10.1099/vir.0.016667-0] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Dengue virus infection is the most frequent arthropod-borne infection affecting humans in the world. Our understanding of the pathophysiological events leading to mild or severe outcomes of the disease remains limited by the fact that viral target cells in the human body are poorly characterized. One of the most sensitive strategies for detecting cells supporting active replication of this positive-strand RNA virus is the search for the replicative intermediate, an antigenome of negative polarity, by RT-PCR. However, a phenomenon described as 'false priming' of the reverse transcriptase (RT) prevents strand-specific detection. The results of the current study showed that this event corresponds to cDNA synthesis that is independent of any primer addition. This property was general to all RNAs tested and was not associated with small free nucleic acids, such as tRNAs and microRNAs. Rather, it corresponded to initiation of cDNA synthesis from the 3' end of the RNA template, and a model is proposed in which the template RNA snaps back upon itself and creates a transient RNA primer suitable for the RT. Such a property would explain why many assays proposed for detection of a replicative intermediate are not specific, and may help in the development of a molecular biology protocol that could allow replication studies of RNA viruses of human interest, such as dengue virus, hepatitis C virus and enteroviruses.
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Affiliation(s)
- A Tuiskunen
- Unité de Virologie Tropicale, IRBA-Marseille (IMTSSA), allée du Med. Col. Jamot, Parc du Pharo, BP 60109, 13262 Marseille Cedex 07, France
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24
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Pandey VN, Upadhyay A, Chaubey B. Prospects for antisense peptide nucleic acid (PNA) therapies for HIV. Expert Opin Biol Ther 2009; 9:975-89. [PMID: 19534584 DOI: 10.1517/14712590903052877] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Since the discovery and synthesis of a novel DNA mimic, peptide nucleic acid (PNA) in 1991, PNAs have attracted tremendous interest and have shown great promise as potential antisense drugs. They have been used extensively as tools for specific modulation of gene expression by targeting translation or transcription processes. This review discusses the present and future therapeutic potential of this class of compound as anti-HIV-1 drugs.
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Affiliation(s)
- Virendra N Pandey
- University of Medicine and Dentistry, New Jersey-New Jersey Medical School, Department of Biochemistry and Molecular Biology, Newark, NJ 07103, USA.
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25
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TRIM28 mediates primer binding site-targeted silencing of Lys1,2 tRNA-utilizing retroviruses in embryonic cells. Proc Natl Acad Sci U S A 2008; 105:12521-6. [PMID: 18713861 DOI: 10.1073/pnas.0805540105] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Murine leukemia viruses (MLVs) and related retroelements are potently restricted in embryonic cells by postintegration transcriptional silencing, likely to protect the germ line from insertional mutagenesis. This silencing is in large part attributable to the presence of a nuclear repression complex, which targets a sequence element of the proviral DNA, the repressor-binding site. The repressor-binding site closely overlaps the tRNA primer binding site, a highly conserved sequence essential for virus replication and defining the site of initiation of DNA synthesis during reverse transcription. We have recently demonstrated that the cellular corepressor TRIM28 is recruited to the proline tRNA primer-binding site used by many MLVs and is required to mediate this silencing. Here, we show that TRIM28 is also required for the restriction of retroviruses using a completely distinct tRNA for the priming of their DNA synthesis, namely Lys-1,2 tRNA. These results generalize the role of TRIM28 in retroviral restriction and suggest that this system has evolved to restrict multiple retroviruses.
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26
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Abbink TEM, Berkhout B. HIV-1 reverse transcription initiation: a potential target for novel antivirals? Virus Res 2008; 134:4-18. [PMID: 18255184 DOI: 10.1016/j.virusres.2007.12.009] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2007] [Revised: 12/14/2007] [Accepted: 12/14/2007] [Indexed: 11/19/2022]
Abstract
Reverse transcription is an essential step in the retroviral life cycle, as it converts the genomic RNA into DNA. In this review, we describe recent developments concerning the initiation step of this complex, multi-step reaction. During initiation of reverse transcription, a cellular tRNA primer is placed onto a complementary sequence in the viral genome, called the primer binding site or PBS. The viral enzyme reverse transcriptase (RT) recognizes this RNA-RNA complex, and catalyzes the extension of the 3' end of the tRNA primer, with the viral RNA (vRNA) acting as template. The initiation step is highly specific and most retroviruses are restricted to the use of the cognate, self-tRNA primer. Human immunodeficiency virus type 1 (HIV-1) uses the cellular tRNA(Lys,3) molecule as primer for reverse transcription. No spontaneous switches in tRNA usage by HIV-1 or other retroviruses have been described and attempts to change the identity of the tRNA primer were unsuccessful in the past. These observations indicate that the virus strongly prefers the self-primer, suggesting that a very specific mechanism for primer selection must exist. Indeed, tRNA primers are selectively packaged into virus particles, are specifically recognized by RT and are placed onto the viral RNA genome via base pairing to the PBS and other sequence motifs, thus rendering a specific initiation complex. Analysis of this critical step in the viral life cycle may result in the discovery of novel antiviral drugs in the battle against HIV/AIDS.
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Affiliation(s)
- Truus E M Abbink
- Laboratory of Experimental Virology, Department of Medical Microbiology, Centre for Infection and Immunity Amsterdam (CINIMA), Academic Medical Centre of the University of Amsterdam, Meibergdreef 15, 1105 AZ, Amsterdam, The Netherlands
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27
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Puglisi EV, Puglisi JD. Probing the conformation of human tRNA(3)(Lys) in solution by NMR. FEBS Lett 2007; 581:5307-14. [PMID: 17963705 DOI: 10.1016/j.febslet.2007.10.026] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2007] [Revised: 10/02/2007] [Accepted: 10/08/2007] [Indexed: 11/24/2022]
Abstract
Human tRNA(3)(Lys) acts as a primer for the reverse transcription of human immunodeficiency virus genomic RNA. To form an initiation complex with genomic RNA, tRNA(3)(Lys) must reorganize its secondary structure. To provide a starting point for mechanistic studies of the formation of the initiation complex, we here present solution NMR investigations of human tRNA(3)(Lys). We use a straightforward set of NMR experiments to show that tRNA(3)(Lys) adopts a standard transfer ribonucleic acid tertiary structure in solution, and that Mg(2+) is required for this folding. The results underscore the power of NMR to reveal rapidly the conformation of RNAs.
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Affiliation(s)
- Elisabetta Viani Puglisi
- Department of Structural Biology, D105A Fairchild Building, 299 Campus Drive West, Stanford University School of Medicine, Stanford, CA 94305-5126, USA
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Abbink TEM, Berkhout B. HIV-1 reverse transcription: close encounters between the viral genome and a cellular tRNA. ADVANCES IN PHARMACOLOGY 2007; 55:99-135. [PMID: 17586313 DOI: 10.1016/s1054-3589(07)55003-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/10/2023]
Affiliation(s)
- Truus E M Abbink
- Laboratory of Experimental Virology, Department of Medical Microbiology, Center for Infection and Immunity Amsterdam, Academic Medical Center of the University of Amsterdam, Meibergdreef 15, Amsterdam, The Netherlands
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Tripathi S, Chaubey B, Barton BE, Pandey VN. Anti HIV-1 virucidal activity of polyamide nucleic acid-membrane transducing peptide conjugates targeted to primer binding site of HIV-1 genome. Virology 2007; 363:91-103. [PMID: 17320140 PMCID: PMC2038983 DOI: 10.1016/j.virol.2007.01.016] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2006] [Revised: 11/06/2006] [Accepted: 01/18/2007] [Indexed: 11/21/2022]
Abstract
We have shown that polyamide nucleic acids (PNAs) targeted to the PBS (PNA(PBS)) and A-loop (PNA(A-loop)) sequences, when transfected into cells, inhibit HIV-1 replication by blocking the initiation of reverse transcription via destabilizing tRNA(3)(Lys) primer from the viral genome. Here we demonstrate that both PNA(PBS) and PNA(A-loop) conjugated with the membrane-transducing peptide (MTD) vectors penetratin and Tat are rapidly taken up by cells and inhibit HIV-1 replication. Moreover, MTD peptide conjugates of PNA(PBS) and PNA(A-loop) displayed potent virucidal activity against HIV-1. Brief exposure of HIV-1 virions to these conjugates rendered them noninfectious. The IC(50) values for virucidal activity were in the range of approximately 50 nM; IC(50) values for inhibition of HIV-1 replication/infection were 0.5 microM-0.7 microM. The virucidal property of these conjugates suggests that a cocktail of anti-HIV-1 PNA-MTD peptide conjugates targeting critical regions of the HIV-1 genome could serve as a prophylactic agent for inactivating HIV-1 virions after exposure to HIV-1.
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Affiliation(s)
- Snehlata Tripathi
- Department of Biochemistry and Molecular Biology, UMDNJ-New Jersey Medical School, 185 South Orange Avenue, Newark, NJ 07103
| | - Binay Chaubey
- Department of Biochemistry and Molecular Biology, UMDNJ-New Jersey Medical School, 185 South Orange Avenue, Newark, NJ 07103
| | - Beverly E. Barton
- Division of Urology, Department of Surgery, UMDNJ-New Jersey Medical School, 185 South Orange Avenue, Newark, NJ 07103
| | - Virendra N. Pandey
- Department of Biochemistry and Molecular Biology, UMDNJ-New Jersey Medical School, 185 South Orange Avenue, Newark, NJ 07103
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Kelly MC, Kosloff BR, Morrow CD. Forced selection of tRNA(Glu) reveals the importance of two adenosine-rich RNA loops within the U5-PBS for SIV(smmPBj) replication. Virology 2007; 366:330-9. [PMID: 17543363 PMCID: PMC2040306 DOI: 10.1016/j.virol.2007.04.025] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2007] [Revised: 03/15/2007] [Accepted: 04/25/2007] [Indexed: 11/23/2022]
Abstract
Simian immunodeficiency virus (SIV) and human immunodeficiency virus (HIV-1) preferentially select and use tRNA(Lys,3) as the primer for initiation of reverse transcription. Previous studies have shown that HIV-1 can be forced to use tRNA(Glu) if mutations are made within the primer-binding site (PBS) and a region upstream, A-loop, to be complementary to the 3'-terminal 18 nucleotides and anticodon loop of tRNA(Glu). To examine the primer preference of SIV, mutations were made within the PBS of SIV(smmPBj) to be complementary to tRNA(Glu). Analysis of the production of infectious virus revealed that SIV(smmPBj) with the PBS complementary to tRNA(Glu) retained approximately 80% infectivity of the wild type. However, modification of the U5 of SIV(smmPBj) to alter nucleotides to be complementary to the anticodon of tRNA(Glu), in combination with the PBS complementary to tRNA(Glu), drastically reduced the production of infectious SIV(smmPBj) to less than 1% that of wild type. The replication of SIV(smmPBj) with the PBS complementary to tRNA(Glu) was similar to that of the wild type virus, while the replication of SIV(smmPBj) with PBS and A-loop complementary to tRNA(Glu) was delayed compared to that of wild type virus. Analysis of the PBS regions revealed that the virus with the PBS complementary to tRNA(Glu) reverted quickly, within 4 days, to be complementary to tRNA(Lys,3), while the virus with PBS and A-loop complementary to tRNA(Glu) retained the PBS for a longer time during in vitro culture although following extended replication both the A-loop and PBS of SIV(smmPBj) reverted to be complementary to tRNA(Lys,3). RNA modeling of SIV(smmPBj) U5-PBS by m-fold revealed two potential A-loop regions. Mutations in either A-loop drastically effected replication in human PBMC. Analysis of the A-loops following in vitro replication revealed that both reverted to the wild type sequence. The results of these studies demonstrate that SIV(smmPBj), like HIV-1, preferentially utilizes tRNA(Lys,3) as a primer for reverse transcription for high level replication, but unlike HIV-1 selection may involve the use of two adenosine-rich loops.
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Affiliation(s)
| | | | - Casey D. Morrow
- * Corresponding author: Casey D. Morrow, Department of Cell Biology, University of Alabama at Birmingham, 802 Kaul Building, 720 20 Street South, Birmingham, Alabama 35294 (USA), 205 934 5705 (Phone), 205 934 1580 (FAX),
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McCulley A, Morrow CD. Nucleotides within the anticodon stem are important for optimal use of tRNA(Lys,3) as the primer for HIV-1 reverse transcription. Virology 2007; 364:169-77. [PMID: 17368706 PMCID: PMC2080789 DOI: 10.1016/j.virol.2007.02.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2006] [Revised: 01/18/2007] [Accepted: 02/09/2007] [Indexed: 11/30/2022]
Abstract
HIV-1 utilizes tRNA(Lys,3) as the primer for initiation of reverse transcription. To further examine the tRNA sequence and structural requirements for primer selection, we developed a complementation system which required tRNA(Lys) to be provided in trans. We constructed an HIV-1 provirus in which the primer-binding site (PBS) was altered to be complementary to the 3' terminal 18-nucleotides of E. coli tRNA(Lys,3), which shares many bases with mammalian tRNA(Lys,3), and demonstrated that infectious virus was obtained only if the provirus was co-transfected with the plasmid encoding E. coli tRNA(Lys,3). In the current study we have mutated E. coli tRNA(Lys,3) so that nucleotides within the stem of the anticodon stem-loop were made identical to mammalian tRNA(Lys,3). Analysis of the complementation revealed that the modified E. coli tRNA(Lys,3) (E. coli tRNA(Lys,3)-MA) complemented 3-5 times more efficiently than E. coli tRNA(Lys,3). Mutation of nucleotides within the anticodon stem region of E. coli tRNA(Lys,3)-MA that differed from E. coli tRNA(Lys,3) revealed the importance of the nucleotide sequence for efficient use in reverse transcription. The results of our studies highlight that multiple regions of mammalian tRNA(Lys,3) are important for the preference of tRNA(Lys,3) as the primer for HIV-1 reverse transcription.
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Affiliation(s)
| | - Casey D. Morrow
- Corresponding author: Casey D. Morrow, University of Alabama at Birmingham, Department of Cell Biology, 802 Kaul Building, 720 20th Street, South Birmingham, AL 35294-0024, (205) 934-5705: Phone, (205) 934-5733: FAX,
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Djekic UV, Morrow CD. Analysis of the replication of HIV-1 forced to use tRNAMet(i) supports a link between primer selection, translation and encapsidation. Retrovirology 2007; 4:10. [PMID: 17274824 PMCID: PMC1797187 DOI: 10.1186/1742-4690-4-10] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2006] [Accepted: 02/02/2007] [Indexed: 11/18/2022] Open
Abstract
Background Previous studies have suggested that the process of HIV-1 tRNA primer selection and encapsidation of genomic RNA might be coupled with viral translation. In order to further investigate this relationship, proviruses were constructed in which the primer-binding site (PBS) was altered to be complementary to elongator tRNAMet (tRNAMet(e)) (HXB2-Met(e)) or initiator tRNAMet (tRNAMet(i)) (HXB2-Met(i)). These tRNAMet not only differ with respect to the 3' terminal 18-nucleotides, but also with respect to interaction with host cell proteins during protein synthesis. Results Consistent with previous studies, HXB2-Met(e) were infectious and maintained this PBS following short-term in vitro culture in SupT1 cells. In contrast, transfection of HBX2-Met(i) produced reduced amounts of virus (as determined by p24) and did not establish a productive infection in SupT1 cells. The low infectivity of the virus with the PBS complementary to tRNAMet(i) was not due to differences in endogenous levels of cellular tRNAMet(i) compared to tRNAMet(e); tRNAMet(i) was also capable of being selected as the primer for reverse transcription as determined by the endogenous reverse transcription reaction. The PBS of HXB2-Met(i) contains an ATG, which could act as an upstream AUG and syphon scanning ribosomes thereby reducing initiation of translation at the authentic AUG of Gag. To investigate this possibility, a provirus with an A to G change was constructed (HXB2-Met(i)AG). Transfection of HXB2-Met(i)AG resulted in increased production of virus, similar to that for the wild type virus. In contrast to HXB2-Met(i), HXB2-Met(i)AG was able to establish a productive infection in SupT1 cells. Analysis of the PBS following replication revealed the virus favored the genome with the repaired PBS (A to G) even though tRNAMet(i) was continuously selected as the primer for reverse transcription. Conclusion The results of these studies suggest that HIV-1 has access to both tRNAMet for selection as the replication primer and supports a co-ordination between primer selection, translation and encapsidation during virus replication.
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Affiliation(s)
- Uros V Djekic
- Department of Cell Biology, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
| | - Casey D Morrow
- Department of Cell Biology, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
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Ni N, Xu W, Morrow CD. Importance of A-loop complementarity with tRNAHis anticodon for continued selection of tRNAHis as the HIV reverse transcription primer. Virol J 2007; 4:4. [PMID: 17214904 PMCID: PMC1785369 DOI: 10.1186/1743-422x-4-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2006] [Accepted: 01/10/2007] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Human immunodeficiency virus (HIV-1) preferentially selects tRNALys,3 as the primer for reverse transcription. HIV-1 can be forced to select alternative tRNAs through mutation in the primer-binding site (PBS) and a region upstream of the PBS designated as the A-loop. Alteration of the PBS and A-loop to be complementary to the 3' terminal nucleotides and anticodon of tRNAHis results in HIV-1 that can stably utilize this tRNA for replication. RESULTS In the current study, we have investigated the effect that mutations within the A-loop have on the stability of HIV-1 with a PBS complementary to tRNAHis. For these studies, we have altered the A-loop to be complementary to tRNAMet, tRNAGln, tRNAIle, tRNAThr and tRNASer. All substitutions of the A-loops with the PBS complementary to tRNAHis resulted in a reduction of infectious virus obtained following transfection of proviral genomes in the 293T cells. Virus replication in SupT1 cells was also impaired as a result of the alteration of the A-loop. Viruses with the A-loop complementary to tRNALys,3 and tRNASer reverted to utilize tRNALys,3 following in vitro replication. In contrast, viruses with the A-loop complementary to the other tRNAs remained stable and continued to use tRNAHis. RNA modeling of the stem-loop structure revealed that nucleotides were displayed on the loop region that could potentially interact with the anticodon of tRNAHis. To further explore the effects of the A-loop mutations on virus replication, the A-loops complementary to tRNASer or tRNAHis were cloned into the wild type genome with the PBS complementary to tRNALys,3. Transfection of proviral genomes which contained the wild type PBS and A-loops complementary to tRNASer or tRNAHis into 293 T cells did not impact on the production of viruses as measured by p24 antigen ELISA. However, viruses with the A-loop complementary to tRNAHis had greatly reduced infectivity and replicated poorly in SupT1 compared to the wild type or viruses with the A-loop complementary to tRNASer. CONCLUSION These studies demonstrate that complementarity of A-loop region with the anticodon of tRNAHis has a pronounced effect on the capacity of HIV-1 to utilize tRNAHis as the primer for reverse transcription. Complementarity between A-loop and anticodon of the tRNA then is important for the selection of the tRNA primer used for reverse transcription.
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Affiliation(s)
- Na Ni
- Department of Cell Biology, University of Alabama at Birmingham, Birmingham, AL 35294-0024, USA
| | - Wenqin Xu
- Department of Cell Biology, University of Alabama at Birmingham, Birmingham, AL 35294-0024, USA
| | - Casey D Morrow
- Department of Cell Biology, University of Alabama at Birmingham, Birmingham, AL 35294-0024, USA
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Ni N, Morrow CD. Impact of forced selection of tRNAs on HIV-1 replication and genome stability highlight preferences for selection of certain tRNAs. Virus Res 2006; 124:29-37. [PMID: 17070952 PMCID: PMC1847643 DOI: 10.1016/j.virusres.2006.09.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2006] [Revised: 09/22/2006] [Accepted: 09/25/2006] [Indexed: 01/19/2023]
Abstract
Human immunodeficiency virus (HIV-1) exclusively selects tRNA(Lys,3) as the primer for initiation of reverse transcription. How and why HIV-1 selects the tRNA is unresolved. To address this issue, we have generated HIV-1 in which the PBS was changed to be complementary to alternative tRNAs. In this study, we report on HIV-1 that have the PBS mutated to be complementary to tRNA(Thr), tRNA(Phe), tRNA(Ser) and tRNA(Tyr). Virus with a PBS complementary to tRNA(Thr) grew slightly slower than the wild type virus and maintained the PBS for an extended culture period before finally reverting back to utilize tRNA(Lys,3). In contrast, viruses with a PBS complementary to tRNA(Phe) or tRNA(Ser) rapidly reverted to utilize tRNA(Lys,3) following limited in vitro replication, while a virus with a PBS complementary to tRNA(Tyr) had severely compromised infectivity and did not productively infect a continuous T cell line (SupT1) or human peripheral blood mononuclear cells (PBMC). Modification of the A-loop region to be complementary to tRNA(Thr) with the mutation in the PBS to be complementary to tRNA(Thr) resulted in a virus that could stably utilize this tRNA while the modification of the A-loop to be complementary to the anticodon of tRNA(Ser) did not allow the virus to stably utilize tRNA(Ser). Modification of the A-loop region to be complementary to the anticodon of tRNA(Phe) severely impacted the replication of this virus. Finally, the modification of the A-loop region to be complementary to tRNA(Tyr) did not rescue the virus with a PBS complementary to tRNA(Tyr). The results of these studies demonstrate the diverse effects that alteration of the PBS to force selection of alternative primers have on HIV-1 replication and provide a framework to understand the dynamics of primer selection.
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Affiliation(s)
| | - Casey D. Morrow
- Corresponding author: Casey D. Morrow, University of Alabama at Birmingham, Department of Cell Biology, 802 Kaul Building, 720 20 Street, South Birmingham, AL 35294-0024, (205) 934-5705: Phone (205) 934-5733: FAX
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McCulley A, Morrow CD. Complementation of human immunodeficiency virus type 1 replication by intracellular selection of Escherichia coli formula supplied in trans. J Virol 2006; 80:9641-50. [PMID: 16973568 PMCID: PMC1617247 DOI: 10.1128/jvi.00709-06] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Human immunodeficiency virus type 1 (HIV-1) exclusively selects tRNA3Lys as the primer for the initiation of reverse transcription, even though both tRNA3Lys and tRNA1,2Lys are found in HIV-1 virions. Alteration of the HIV-1 primer-binding site (PBS) to be complementary to alternate tRNAs results in the use of those tRNAs for replication, indicating that primer complementarity with the PBS is an important determinant of primer selection. In previous studies, we have exploited this fact to develop a system in which yeast (Saccharomyces cerevisiae) tRNAPhe is provided in trans to complement the replication of HIV-1 with a PBS complementary to yeast tRNAPhe. Recent studies have demonstrated that the presence of lysyl-tRNA synthetase in HIV-1 virions might account for the preference for the selection of tRNA3Lys in HIV-1 replication. To establish a complementation system more reflective of HIV-1 primer selection, we have altered the HIV-1 PBS to be complementary to the Escherichia coli tRNA3Lys, which shares near identity with mammalian tRNA3Lys except in the 3'-terminal 18-nucleotide sequence that binds to the PBS. E. coli tRNA3Lys expressed from a plasmid was aminoacylated in mammalian cells. Cotransfection of cells with a plasmid that encodes E. coli tRNA3Lys and a plasmid encoding an HIV-1 provirus with a PBS complementary to E. coli tRNA3Lys resulted in the production of infectious virus. A comparison of the two complementation systems revealed that higher levels of intracellular E. coli tRNA3Lys than of yeast tRNAPhe were needed to achieve equal levels of infectious virus, indicating that there was no preferential selection of E. coli tRNA3Lys. To examine the specificity of tRNALys selection, E. coli tRNA3Lys was modified to tRNA1,2Lys. This tRNA was also aminoacylated when expressed in mammalian cells and complemented the infectivity of HIV-1 at levels similar to those seen for E. coli tRNA3Lys. Additional mutations in the anticodon of E. coli tRNA3Lys were constructed; these mutations did not significantly correlate with the capacity of the tRNA primer to complement infectivity of HIV-1, even though they had a drastic effect on the aminoacylation of the tRNAs. The results of these studies demonstrate that E. coli tRNA3Lys provided in trans can complement HIV-1 genomes with the PBS altered to E. coli tRNA3Lys. However, the capacity of tRNA3Lys to interact with lysyl-tRNA synthetase does not entirely explain the enhanced preference for selection of tRNA3Lys for the replication of HIV-1.
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Affiliation(s)
- Anna McCulley
- University of Alabama at Birmingham, Department of Cell Biology, 802 Kaul Building, 720 20th Street South, Birmingham, AL 35294-0024, USA
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Li M, Eipers PG, Ni N, Morrow CD. HIV-1 designed to use different tRNAGln isoacceptors prefers to select tRNAThr for replication. Virol J 2006; 3:80. [PMID: 17002807 PMCID: PMC1592299 DOI: 10.1186/1743-422x-3-80] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2006] [Accepted: 09/26/2006] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Previous studies have shown that infection with human immunodeficiency virus type 1 (HIV-1) causes acceleration of the synthesis of glutamine tRNA (tRNAGln) in infected cells. To investigate whether this might influence HIV-1 to utilize tRNAGln as a primer for initiation of reverse transcription, we have constructed HIV-1 proviral genomes in which the PBS and the A-loop region upstream of the PBS have been made complementary to either the anticodon region of tRNAGln,1 or tRNAGln,3 and 3' terminal 18 nucleotides of each isoacceptor of tRNAGln. RESULTS Viruses in which the PBS was altered to be complementary to tRNAGln,1 or tRNAGln,3 with or without the A-loop all exhibited a lower infectivity than the wild type virus. Viruses with only the PBS complementary to tRNAGln,1 or tRNAGln,3 reverted to wild type following culture in SupT1 cells. Surprisingly, viruses in which the PBS and A-loop were complementary to tRNAGln,1 did not grow in SupT1 cells, while viruses in which the PBS and A-loop were made complementary to tRNAGln,3 grew slowly in SupT1 cells. Analysis of the PBS of this virus revealed that it had reverted to select tRNAThr as the primer, which shares complementarity in 15 of 18 nucleotides with the PBS complementary to tRNAGln,3. CONCLUSION The results of these studies support the concept that the HIV-1 has preferred tRNAs that can be selected as primers for replication.
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Affiliation(s)
- Meng Li
- Department of Cell Biology, University of Alabama at Birmingham, 35294-0024 Birmingham, AL, USA
| | - Peter G Eipers
- Department of Cell Biology, University of Alabama at Birmingham, 35294-0024 Birmingham, AL, USA
| | - Na Ni
- Department of Cell Biology, University of Alabama at Birmingham, 35294-0024 Birmingham, AL, USA
| | - Casey D Morrow
- Department of Cell Biology, University of Alabama at Birmingham, 35294-0024 Birmingham, AL, USA
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Xu W, Morrow CD. The G490E mutation in reverse transcriptase does not impact tRNA primer selection by HIV-1 with altered PBS and A-loop. Virology 2006; 352:380-9. [PMID: 16781756 DOI: 10.1016/j.virol.2006.04.019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2006] [Revised: 03/29/2006] [Accepted: 04/11/2006] [Indexed: 10/24/2022]
Abstract
The initiation of HIV-1 reverse transcription utilizes a cellular tRNA(Lys,3) as a primer. The 3' terminal 18-nucleotides of the cellular tRNA(Lys,3) are complementary to a region on the viral genome, designated as the primer binding site (PBS). Previous studies have shown that forcing HIV-1 to utilize alternative tRNA primers through alteration of the PBS results in viruses that revert to utilize tRNA(Lys,3) following in vitro replication. In some instances though, HIV-1 has been shown to select alternative tRNAs for initiation of reverse transcription if additional mutations upstream in the U5 region (A-loop) were made to be complementary to these alternative tRNAs. Recently, an HIV-1 has been described in which the U5 region distinct from the A-loop, designated as the primer activation site (PAS), was mutated in conjunction with the PBS to force the virus to use tRNA(Lys1,2) as a primer. An additional mutation in reverse transcriptase (RT), G490E, was found to facilitate the forced use of tRNA(Lys1,2) as the primer. In the current study, we have investigated the impact of the G490E mutation in RT on the selection and use of alternative primers by HIV-1. Viruses were first constructed in which the PBS and A-loop region were made complementary to tRNA(Trp). Previous studies from our laboratory have shown that these viruses are unstable and mutate to select tRNA(Met) or tRNA(Lys1,2). Analysis of the replication of viruses with the U5 and PBS complementary to tRNA(Trp) with or without the G490E mutation revealed no significant differences with respect to infectivity and viral growth in SupT1 or peripheral blood mononuclear cells (PBMC). In addition, the presence of the G490E mutation did not influence the capacity of this virus to revert to utilize tRNA(Met) as the primer for initiation of reverse transcription. In a previous study, we have described an HIV-1 that has been forced to utilize tRNA(Lys1,2) through mutations in the A-loop and PBS. The G490E RT mutation in this virus did not impact on the virus infectivity or growth in SupT1 or PBMC. We did not find a significant fitness advantage to viruses in which the A-loop and PBS were made complementary to tRNA(Lys1,2) that also contained the G490E mutation in RT. The results of these studies then establish that HIV-1 can be forced to use alternative primers through mutations in the U5 (PAS or A-loop) for certain tRNAs. Furthermore, for mutations in the A-loop and PBS, the RT does not play an important role in dictating the selection of the alternative primers to be used for initiation of reverse transcription.
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Affiliation(s)
- Wenqin Xu
- Department of Cell Biology, University of Alabama at Birmingham, Birmingham, AL 35294-0024, USA
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Eberhardy SR, Goncalves J, Coelho S, Segal DJ, Berkhout B, Barbas CF. Inhibition of human immunodeficiency virus type 1 replication with artificial transcription factors targeting the highly conserved primer-binding site. J Virol 2006; 80:2873-83. [PMID: 16501096 PMCID: PMC1395442 DOI: 10.1128/jvi.80.6.2873-2883.2006] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The human immunodeficiency virus type 1 (HIV-1) primer-binding site (PBS) is a highly conserved region in the HIV genome and represents an attractive target for the development of new anti-HIV therapies. In this study, we designed four artificial zinc finger transcription factors to bind at or adjacent to the PBS and repress transcription from the HIV-1 long terminal repeat (LTR). These proteins bound to the LTR in vivo, as demonstrated by the chromatin immunoprecipitation assay. In transient reporter assays, three of the four proteins repressed transcription of a reporter driven by the HIV-1 LTR. Only one of these proteins, however, designated KRAB-PBS2, was able to prevent virus production when transduced into primary lymphocytes. We observed >90% inhibition of viral replication over the course of several weeks compared to untransduced cells, and no significant cytotoxicity was observed. Long-term exposure of HIV-1 to KRAB-PBS2 induced mutations in the HIV-1 PBS that reduced the effectiveness of the repressor, but these mutations also resulted in decreased rates of viral replication. These results show that KRAB-PBS2 has the potential to be used in antiviral therapy for AIDS patients and might complement other gene-based strategies.
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Affiliation(s)
- Scott R Eberhardy
- The Skaggs Institute for Chemical Biology, La Jolla, California 92037, USA
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Ozanick S, Krecic A, Andersland J, Anderson JT. The bipartite structure of the tRNA m1A58 methyltransferase from S. cerevisiae is conserved in humans. RNA (NEW YORK, N.Y.) 2005; 11:1281-90. [PMID: 16043508 PMCID: PMC1370811 DOI: 10.1261/rna.5040605] [Citation(s) in RCA: 110] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Among all types of RNA, tRNA is unique given that it possesses the largest assortment and abundance of modified nucleosides. The methylation at N(1) of adenosine 58 is a conserved modification, occurring in bacterial, archaeal, and eukaryotic tRNAs. In the yeast Saccharomyces cerevisiae, the tRNA 1-methyladenosine 58 (m(1)A58) methyltransferase (Mtase) is a two-subunit enzyme encoded by the essential genes TRM6 (GCD10) and TRM61 (GCD14). While the significance of many tRNA modifications is poorly understood, methylation of A58 is known to be critical for maintaining the stability of initiator tRNA(Met) in yeast. Furthermore, all retroviruses utilize m(1)A58-containing tRNAs to prime reverse transcription, and it has been shown that the presence of m(1)A58 in human tRNA(3) (Lys) is needed for accurate termination of plus-strand strong-stop DNA synthesis during HIV-1 replication. In this study we have identified the human homologs of the yeast m(1)A Mtase through amino acid sequence identity and complementation of trm6 and trm61 mutant phenotypes. When coexpressed in yeast, human Trm6p and Trm61p restored the formation of m(1)A in tRNA, modifying both yeast initiator tRNA(Met) and human tRNA(3) (Lys). Stable hTrm6p/hTrm61p complexes purified from yeast maintained tRNA m(1)A Mtase activity in vitro. The human m(1)A Mtase complex also exhibited substrate specificity--modifying wild-type yeast tRNA(i) (Met) but not an A58U mutant. Therefore, the human tRNA m(1)A Mtase shares both functional and structural homology with the yeast tRNA m(1)A Mtase, possessing similar enzymatic activity as well as a conserved binary composition.
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Affiliation(s)
- Sarah Ozanick
- Department of Biological Sciences, Marquette University, Milwaukee, WI 53201, USA
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Wei M, Cen S, Niu M, Guo F, Kleiman L. Defective replication in human immunodeficiency virus type 1 when non-primers are used for reverse transcription. J Virol 2005; 79:9081-7. [PMID: 15994802 PMCID: PMC1168737 DOI: 10.1128/jvi.79.14.9081-9087.2005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
tRNA(3Lys), the primer for reverse transcriptase in human immunodeficiency virus type 1 (HIV-1), anneals to the primer binding site (PBS) in HIV-1 RNA. It has been shown that altering the PBS and U5 regions upstream of the PBS in HIV-1 so as to be complementary to sequences in tRNA(Met) or tRNA(His) will allow these tRNA species to be stably used as primers for reverse transcription. We have examined the replication of these mutant viruses in Sup-T1 cells. When Sup-T1 cells are infected by cocultivation with HIV-1-transfected 293T cells, viruses using tRNA(His) or tRNA(Met) are produced at rates that are approximately 1/10 or 1/100, respectively, of rates for wild-type virions that use tRNA(3Lys). When Sup-T1 cells are directly infected with equal amounts of these different viruses isolated from the culture supernatant of transfected 293T cells, virions using tRNA(Met) are produced at 1/100 the rate of wild-type viruses, and production of virions using tRNA(His) is not detected. Both wild-type and mutant virions selectively package tRNA(Lys) only, and examination of the ability of total viral RNA to prime reverse transcription in vitro indicates a >80% reduction in the annealing of tRNA(His) or tRNA(Met) to the mutant viral RNAs. PCR analysis of which of the three primer tRNAs is used indicates that only tRNA(3Lys) is detected as primer in wild-type virions and only tRNA(His) is detected as primer in virions containing a PBS complementary to tRNA(His), while the mutant viruses containing a PBS complementary to tRNA(Met) use both tRNA(Met) and tRNA(1,2Lys) as primer tRNAs.
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Affiliation(s)
- Min Wei
- Lady Davis Institute for Medical Research, Jewish General Hospital, 3755 Cote Ste-Catherine Road, Montreal, Quebec, Canada H3T 1E2
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Palmer MT, McPherson S, Morrow CD. Murine leukemia virus with a primer-binding site complementary to tRNALys,3 adapts to select new tRNAs for replication following extended in vitro culture. Virology 2005; 333:337-48. [PMID: 15721366 DOI: 10.1016/j.virol.2004.12.033] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2004] [Revised: 11/10/2004] [Accepted: 12/29/2004] [Indexed: 11/20/2022]
Abstract
The preference of MuLV for the selection of tRNA(Pro) as a replication primer was investigated by altering the primer-binding site (PBS) to be complementary to tRNA(Lys,3). MuLV-based vectors with a PBS complementary to tRNA(Lys,3) were found to be approximately 2-fold less infectious than vectors with the wild-type PBS complementary to tRNA(Pro). MuLV with a PBS complementary to tRNA(Lys,3) was replication competent and maintained the PBS during early stages of in vitro culture. Upon extended culture, PBS were isolated which were complementary to tRNA(Arg). A second MuLV was generated in which the region upstream of the PBS which is predicted to form an RNA stem loop structure was altered so that the nucleotide sequence within the loop would be complementary to the anticodon of tRNA(Lys,3). The virus with both the U5 and PBS complementary to tRNA(Lys,3) was also replication competent. Upon extended in vitro culture though, this virus reverted to utilize tRNA(Lys1,2). Analysis of the infectivity and replication of the wild-type and mutant viruses revealed that tRNA(Pro) was the preferred tRNA for high-level replication. Viruses with a PBS complementary to tRNA(Arg) or tRNA(Ly1,2) replicated at levels approximately 30% and 10% as effective as the wild-type virus, while virus with a PBS complementary to tRNA(Lys,3) had the slowest replication kinetics and least infectivity. Comparison of the virion tRNA content of the wild-type and mutant viruses revealed similar ratios with respect to levels of tRNA(Pro), tRNA(Arg) and tRNA(Lys). Modeling of the U5-PBS region revealed that the predicted RNA structure for the virus that selected tRNA(Arg) was more similar to the wild type virus that uses tRNA(Pro) than the virus which use tRNA(Lys1,2) or tRNA(Lys,3); the virus that uses tRNA(Lys,3) had the most profound disruption in the predicted RNA structure. The results of these studies demonstrate that MuLV has evolved to preferentially select tRNA(Pro) for high-level replication and are discussed with respect to common features of the primer selection process between MuLV and other retroviruses.
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Affiliation(s)
- Matthew T Palmer
- Department of Cell Biology, University of Alabama at Birmingham, 720 20th Street, South, Birmingham, AL 35294-0024, USA
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42
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Das AT, Vink M, Berkhout B. Alternative tRNA priming of human immunodeficiency virus type 1 reverse transcription explains sequence variation in the primer-binding site that has been attributed to APOBEC3G activity. J Virol 2005; 79:3179-81. [PMID: 15709038 PMCID: PMC548477 DOI: 10.1128/jvi.79.5.3179-3181.2005] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
It is generally assumed that human immunodeficiency virus type 1 (HIV-1) uses exclusively the cellular tRNA(3)(Lys) molecule as a primer for reverse transcription. We demonstrate that HIV-1 uses not only tRNA(3)(Lys) but also an alternative tRNA primer. This tRNA was termed tRNA(5)(Lys), and the near completion of the human genome project has allowed the identification of four tRNA(5)(Lys)encoding genes. Priming with tRNA(5)(Lys) results in a single nucleotide polymorphism in the viral primer-binding site that is present in multiple natural and laboratory HIV isolates. This sequence variation was recently attributed to APOBEC3G activity. However, our results show that alternative tRNA priming can cause this mutation in the absence of APOBEC3G.
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Affiliation(s)
- Atze T Das
- Department of Human Retrovirology, Academic Medical Center, University of Amsterdam, Meibergdreef 15, 1105 AZ Amsterdam, The Netherlands
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43
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Han W, Wind-Rotolo M, Kirkman RL, Morrow CD. Inhibition of human immunodeficiency virus type 1 replication by siRNA targeted to the highly conserved primer binding site. Virology 2005; 330:221-32. [PMID: 15527848 DOI: 10.1016/j.virol.2004.09.027] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2004] [Revised: 08/23/2004] [Accepted: 09/20/2004] [Indexed: 11/23/2022]
Abstract
The initiation of HIV-1 reverse transcription occurs at an 18-nucleotide sequence in the viral genome designated as the primer binding site (PBS), which is complementary to the 3' terminal nucleotides of tRNA(Lys,3). Since the PBS is highly conserved among all infectious HIV-1, it represents an attractive target for the development of new therapeutics to inhibit viral replication. In this study, we have evaluated three approaches using small interfering RNA (siRNAs) targeted to the PBS for the capacity to inhibit HIV-1 replication. In the first, transfection of a 21-nucleotide siRNA complementary to the PBS into cells inhibited production of HIV-1 following infection. Control siRNAs of the same length complementary to HIV-1 gag mRNA or to gfp mRNA decreased the production of virus or had no effect on virus replication, respectively. Analysis of the PBS of integrated proviruses derived from viruses that ultimately grew in cultures transfected with siRNA all contained wild-type PBS sequence, demonstrating that HIV-1 did not mutate to escape inhibition by siRNA. In the second approach, hairpin siRNA targeted to the wild-type PBS were expressed using an adeno-associated virus (AAV) vector. HIV-1 replication was inhibited in cells infected with AAV encoding the siRNA to the wild-type PBS, but not in cells infected with AAV encoding an siRNA of the same length targeted to an irrelevant PBS. Finally, studies from this laboratory have shown that alteration of the PBS to be complementary to tRNAHis results in the production of infectious virus that rapidly reverts to utilize tRNALys,3 following in vitro culture. A proviral genome containing a PBS complementary to tRNAHis that encodes an siRNA molecule complementary to the wild-type PBS under control of a U6 promoter within the nef gene was as infectious as the parent HIV-1 genome containing no insert in nef. The virus with the PBS only complementary to tRNAHis reverted to use tRNALys,3, coincident with rapid virus growth, while the virus encoding siRNA grew slower than the virus without siRNA and maintained the PBS complementary to tRNAHis longer in culture. At later times of infection, viruses with the PBS complementary to tRNAHis and the siRNA exhibited a rapid increase in p24 antigen in the culture. Analysis of the PBS revealed that it was now complementary to tRNALys,3. Analysis of the gene encoding the siRNA revealed that the reversion of the PBS coincided with the deletion of the gene encoding siRNA. The results of these studies show that siRNA targeted to the PBS of HIV-1 can inhibit virus replication, supporting the concept that HIV-1 has evolved a strong preference to select tRNALys,3 for high-level replication and establishing the PBS and primer selection as a potential target for new therapeutics.
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Affiliation(s)
- Wenlong Han
- Department of Cell Biology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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44
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Moore-Rigdon KL, Kosloff BR, Kirkman RL, Morrow CD. Preferences for the selection of unique tRNA primers revealed from analysis of HIV-1 replication in peripheral blood mononuclear cells. Retrovirology 2005; 2:21. [PMID: 15790410 PMCID: PMC1084362 DOI: 10.1186/1742-4690-2-21] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2005] [Accepted: 03/24/2005] [Indexed: 12/23/2022] Open
Abstract
Background All human immunodeficiency virus (HIV-1) uses a host tRNALys,3 as the primer for reverse transcription. The tRNALys,3 is bound to a region on the HIV-1 genome, the primer-binding site (PBS), that is complementary to the 18 terminal nucleotides of tRNALys,3. How HIV-1 selects the tRNA from the intracellular milieu is unresolved. Results HIV-1 tRNA primer selection has been investigated using viruses in which the primer-binding site (PBS) and a sequence within U5 were altered so as to be complementary to tRNAMet, tRNAPro or tRNAIle. Analysis of the replication of these viruses in human peripheral blood mononuclear cells (PBMC) revealed preferences for the selection of certain tRNAs. HIV-1 with the PBS altered to be complementary to tRNAMet, with and without the additional mutation in U5 to be complementary to the anticodon of tRNAMet, stably maintains the PBS complementary to tRNAMet following extended in vitro culture in PBMC. In contrast, viruses with either the PBS or PBS and U5 mutated to be complementary to tRNAIle were unstable during in vitro replication in PBMC and reverted to utilize tRNALys,3. Viruses with the PBS altered to be complementary to tRNAPro replicated in PBMC but reverted to use tRNALys,3; viruses with mutations in both the U5 and PBS complementary to tRNAPro maintained this PBS, yet replicated poorly in PBMC. Conclusion The results of these studies demonstrate that HIV-1 has preferences for selection of certain tRNAs for high-level replication in PBMC.
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MESH Headings
- Binding Sites
- DNA Primers
- HIV Reverse Transcriptase
- HIV-1/genetics
- HIV-1/metabolism
- HIV-1/physiology
- Humans
- Leukocytes, Mononuclear/virology
- Mutation
- RNA, Transfer, Amino Acid-Specific/genetics
- RNA, Transfer, Amino Acid-Specific/metabolism
- RNA, Transfer, Lys/metabolism
- RNA, Viral/metabolism
- Ribonucleoprotein, U5 Small Nuclear/genetics
- Transcription, Genetic
- Virus Replication
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Affiliation(s)
- Kenda L Moore-Rigdon
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
| | - Barry R Kosloff
- Department of Cell Biology, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
| | - Richard L Kirkman
- Department of Cell Biology, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
| | - Casey D Morrow
- Department of Cell Biology, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
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Renda MJ, Bradel-Tretheway B, Planelles V, Bambara RA, Dewhurst S. Inhibition of HIV type 1 replication using lentiviral-mediated delivery of mutant tRNA(Lys3)A58U. AIDS Res Hum Retroviruses 2004; 20:1324-34. [PMID: 15650425 DOI: 10.1089/aid.2004.20.1324] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
In previous studies, we showed that residue A58 of cellular tRNALys3 is necessary for appropriate termination of viral plus-strand strong-stop DNA (+SS DNA), and therefore plays a critical role in the life cycle of HIV-1. We also performed proof-of-principle studies that established that a mutant form of this tRNA primer (tRNA(Lys3)A58U, which lacks the M1A58 residue necessary for +SS DNA termination) could inhibit HIV-1 replication. In the present work, we examined whether a third generation lentiviral vector (SIN) could be used to deliver tRNA(Lys3)A58U to CEM cells. Using both viral kinetic studies and limiting dilution assays (LDA), we observed significant impairment of HIV-1 replication, up to 3 logs in the LDA, in CEM sublines expressing mutant tRNA(Lys3)A58U. No inhibition occurred in cells that either expressed wild-type tRNA(Lys3) or were transduced with empty SIN vector. Further, we observed impairment of viral replication using primary isolates of both HIV-1 and HIV-2 in sublines containing tRNA(Lys3)A58U. We also detected "breakthrough" HIV-1 replication in some tRNA(Lys3)A58U-expressing cultures. Interestingly, analyzed breakthrough viruses appeared to be both genetically and phenotypically wild type. One possible explanation for virological breakthrough is that it reflects the gradual accumulation of HIV-1 within the infected cell culture, to a level that ultimately exceeds the containment "threshold" conferred by tRNA(Lys3)A58U. The fact that HIV-1 does not appear to acquire heritable resistance to tRNA(Lys3)A58U-mediated blockade differentiates this antiviral modality from other therapeutic interventions. It also suggests that tRNA-mediated inhibition of viral replication might be a valuable adjunct to other antiviral approaches.
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Affiliation(s)
- Matthew J Renda
- Department of Biochemistry, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642, USA
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46
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Abbink TEM, Beerens N, Berkhout B. Forced selection of a human immunodeficiency virus type 1 variant that uses a non-self tRNA primer for reverse transcription: involvement of viral RNA sequences and the reverse transcriptase enzyme. J Virol 2004; 78:10706-14. [PMID: 15367637 PMCID: PMC516392 DOI: 10.1128/jvi.78.19.10706-10714.2004] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human immunodeficiency virus type 1 uses the tRNA(3)(Lys) molecule as a selective primer for reverse transcription. This primer specificity is imposed by sequence complementarity between the tRNA primer and two motifs in the viral RNA genome: the primer-binding site (PBS) and the primer activation signal (PAS). In addition, there may be specific interactions between the tRNA primer and viral proteins, such as the reverse transcriptase (RT) enzyme. We constructed viruses with mutations in the PAS and PBS that were designed to employ the nonself primer tRNA(Pro) or tRNA(1,2)(Lys). These mutants exhibited a severe replication defect, indicating that additional adaptation of the mutant virus is required to accommodate the new tRNA primer. Multiple independent virus evolution experiments were performed to select for fast-replicating variants. Reversion to the wild-type PBS-lys3 sequence was the most frequent escape route. However, we identified one culture in which the virus gained replication capacity without reversion of the PBS. This revertant virus eventually optimized the PAS motif for interaction with the nonself primer. Interestingly, earlier evolution samples revealed a single amino acid change of an otherwise well-conserved residue in the RNase H domain of the RT enzyme, implicating this domain in selective primer usage. We demonstrate that both the PAS and RT mutations improve the replication capacity of the tRNA(1,2)(Lys)-using virus.
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MESH Headings
- Amino Acid Substitution
- Base Sequence
- Directed Molecular Evolution
- HIV Long Terminal Repeat
- HIV Reverse Transcriptase/genetics
- HIV Reverse Transcriptase/metabolism
- HIV-1/genetics
- HIV-1/growth & development
- Models, Molecular
- Molecular Sequence Data
- Molecular Structure
- Mutation, Missense
- Nucleic Acid Conformation
- Protein Structure, Tertiary
- RNA/metabolism
- RNA, Transfer/metabolism
- RNA, Transfer, Lys/metabolism
- RNA, Transfer, Pro/metabolism
- RNA, Viral/genetics
- RNA, Viral/metabolism
- Ribonuclease H/genetics
- Ribonuclease H/physiology
- Selection, Genetic
- Transcription, Genetic
- Virus Replication
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Affiliation(s)
- Truus E M Abbink
- Department of Human Retrovirology, Academic Medical Center, University of Amsterdam, Meibergdreef 15, 1105 AZ Amsterdam, The Netherlands
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47
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Palmer MT, Morrow CD. Analysis of murine leukemia virus replication complemented by yeast tRNA(Phe) reveals inherent preferences for the tRNA primer selected for reverse transcription. Virology 2004; 324:430-8. [PMID: 15207628 DOI: 10.1016/j.virol.2004.03.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2004] [Revised: 02/13/2004] [Accepted: 03/15/2004] [Indexed: 11/19/2022]
Abstract
The replication of murine leukemia virus (MuLV) requires the capture of a cellular tRNA(Pro) as a primer for reverse transcription. To further study the specificity of primer selection, we have utilized a defective MuLV in which the primer-binding site (PBS) has been altered to be complementary to a nonmammalian tRNA, yeast tRNA(Phe). Infectivity of the defective MuLV is dependent upon co-expression of yeast tRNA(Phe) in the cell. Defective MuLV genomes have been constructed in which the PBS was altered to be complementary to tRNA(Phe) that also encoded the cDNA for tRNA(Phe). Transfection of these defective proviral genomes into cells resulted in the production of infectious MuLV as determined by a single-round assay. The amount of infectious virus produced using this complementation system, though, was approximately 6-fold lower than that produced following transfection of defective proviral genomes with a wild-type PBS complementary to tRNA(Pro). The lower infectivity was not due to reduced expression of tRNA(Phe) in the transfected cells as compared to endogenous tRNA(Pro) or tRNA(Lys,3). Serial passage of the MuLV genome with a PBS complementary to tRNA(Phe) that encoded tRNA(Phe) resulted in amplification of the virus. Using this rescue system, we have passaged the virus for four serial passages, after which time a revertant genome in which the PBS was altered to be complementary to tRNA(Gln) was detected that grew to high titers following subsequent serial passage. The results of these studies suggest that MuLV has preferences for the tRNA primer used in reverse transcription and are discussed with respect to the mechanism of primer selection.
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Affiliation(s)
- Matthew T Palmer
- Department of Cell Biology, University of Alabama at Birmingham, 720 20th Street South, Birmingham, AL 35294, USA
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48
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Voronin YA, Pathak VK. Frequent dual initiation in human immunodeficiency virus-based vectors containing two primer-binding sites: a quantitative in vivo assay for function of initiation complexes. J Virol 2004; 78:5402-13. [PMID: 15113919 PMCID: PMC400373 DOI: 10.1128/jvi.78.10.5402-5413.2004] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
We previously demonstrated that murine leukemia virus (MLV)-based vectors containing two primer-binding sites (PBSs) have the capacity to initiate reverse transcription more than once (Y. A. Voronin and V. K. Pathak, Virology 312:281-294, 2003). To determine whether human immunodeficiency virus (HIV)-based vectors also have the capacity to initiate reverse transcription twice, we constructed an HIV type 1 (HIV-1)-based vector containing the HIV-1 PBS, a green fluorescent protein reporter gene (GFP), and a second PBS derived from HIV-2 3' of GFP. Simultaneous initiation of reverse transcription at both the 5' HIV-1 PBS and 3' HIV-2 PBS was predicted to result in deletion of GFP. As in the MLV-based vectors, GFP was deleted in approximately 25% of all proviruses, indicating frequent dual initiation in HIV-based vectors containing two PBSs. Quantitative real-time PCR analysis of early reverse transcription products indicated that HIV-1 reverse transcriptase efficiently used the HIV-2 PBS. To investigate tRNA primer-RNA template interactions in vivo, we introduced several mutations in the HIV-2 U5 region. The effects of these mutations on the efficiency of reverse transcription initiation were measured by quantitative real-time PCR analysis of early reverse transcription products, with initiation at the HIV-1 PBS used as an internal control. Disruption of the lower and upper parts of the U5-inverted repeat stem reduced the efficiency of initiation 20- and 6-fold, respectively. In addition, disruption of the proposed interactions between viral RNA and tRNA(Lys3) thymidine-pseudouridine-cytidine and anticodon loops decreased the efficiency of initiation seven- and sixfold, respectively. These results demonstrate the relative influence of various RNA-RNA interactions on the efficiency of initiation in vivo. Furthermore, the two-PBS vector system provides a sensitive and quantitative in vivo assay for analysis of RNA-RNA and protein-RNA interactions that can influence the efficiency of reverse transcription initiation.
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Affiliation(s)
- Yegor A Voronin
- HIV Drug Resistance Program, National Cancer Institute at Frederick, Building 535, Frederick, MD 21702, USA
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49
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Moore KL, Kosloff BR, Kelly NJ, Kirkman RL, Dupuy LC, McPherson S, Morrow CD. HIV type 1 that select tRNA(His) or tRNA(Lys1,2) as primers for reverse transcription exhibit different infectivities in peripheral blood mononuclear cells. AIDS Res Hum Retroviruses 2004; 20:373-81. [PMID: 15157356 DOI: 10.1089/088922204323048122] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The replication in human peripheral blood mononuclear cells (PBMC) of unique HIV-1 that select tRNA(His) or tRNA(Lys1,2) for reverse transcription was compared to the wild-type virus that uses tRNA(Lys,3). HIV-1 with only the primer-binding site (PBS) changed to be complementary to these alternative tRNAs initially replicated more slowly than the wild-type virus in PBMC, although all viruses eventually reached equivalent growth as measured by p24 antigen. Viruses with only a PBS complementary to the 3' terminal 18 nucleotides of tRNA(His) or tRNA(Lys1,2) reverted to use tRNA(Lys3). HIV-1 with mutations in the U5-PBS to allow selection of tRNA(His) and tRNA(Lys1,2) following long-term growth in SupT1 cells were also evaluated for growth and PBS stability following replication in PBMC. Although both viruses initially grew slower than wild type, they maintained a PBS complementary to the starting tRNA and did not revert to the wild-type PBS after long-term culture in PBMC. Analysis of the U5-PBS regions following long-term culture in PBMC also revealed few changes from the starting sequences. The virus that stably used tRNA(His) was less infectious than the wild type. In contrast, the virus that stably used tRNA(Lys1,2) evolved to be as infectious as wild-type virus following extended culture in PBMC. The results of these studies highlight the impact of the host cell on the tRNA primer selection process and subsequent infectivity of HIV-1.
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Affiliation(s)
- Kenda L Moore
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
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50
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Rigourd M, Goldschmidt V, Brulé F, Morrow CD, Ehresmann B, Ehresmann C, Marquet R. Structure-function relationships of the initiation complex of HIV-1 reverse transcription: the case of mutant viruses using tRNA(His) as primer. Nucleic Acids Res 2003; 31:5764-75. [PMID: 14500840 PMCID: PMC206454 DOI: 10.1093/nar/gkg754] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Reverse transcription of HIV-1 RNA is initiated from the 3' end of a tRNA3Lys molecule annealed to the primer binding site (PBS). An additional interaction between the anticodon loop of tRNA3Lys and a viral A-rich loop is required for efficient initiation of reverse transcription of the HIV-1 MAL isolate. In the HIV-1 HXB2 isolate, simultaneous mutations of the PBS and the A-rich loop (mutant His-AC), but not of the PBS alone (mutant His) allows the virus to stably utilize tRNA(His) as primer. However, mutant His-AC selects additional mutations during cell culture, generating successively His-AC-GAC and His-AC-AT-GAC. Here, we wanted to establish direct relationships between the evolution of these mutants in cell culture, their efficiency in initiating reverse transcription and the structure of the primer/template complexes in vitro. The initiation of reverse transcription of His and His-AC RNAs was dramatically reduced. However, His-AC-GAC RNA, which incorporated three adaptative point mutations, was reverse transcribed more efficiently than the wild type RNA. Incorporation of two additional mutations decreased the efficiency of the initiation of reverse transcription, which remained at the wild type level. Structural probing showed that even though both His-AC and His-AC-GAC RNAs can potentially interact with the anticodon loop of tRNA(His), only the latter template formed a stable interaction. Thus, our results showed that the selection of adaptative mutations by HIV-1 mutants utilizing tRNA(His) as primer was initially dictated by the efficiency of the initiation of reverse transcription, which relied on the existence of a stable interaction between the mutated A-rich loop and the anticodon loop of tRNA(His).
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Affiliation(s)
- Mickaël Rigourd
- Unité Propre de Recherche 9002 du CNRS conventionnée à l'Université Louis Pasteur, IBMC, 15 rue René Descartes, 67084 Strasbourg cedex, France
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