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Ye L, Gribling-Burrer AS, Bohn P, Kibe A, Börtlein C, Ambi UB, Ahmad S, Olguin-Nava M, Smith M, Caliskan N, von Kleist M, Smyth RP. Short- and long-range interactions in the HIV-1 5' UTR regulate genome dimerization and packaging. Nat Struct Mol Biol 2022; 29:306-319. [PMID: 35347312 PMCID: PMC9010304 DOI: 10.1038/s41594-022-00746-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 02/14/2022] [Indexed: 11/09/2022]
Abstract
RNA dimerization is the noncovalent association of two human immunodeficiency virus-1 (HIV-1) genomes. It is a conserved step in the HIV-1 life cycle and assumed to be a prerequisite for binding to the viral structural protein Pr55Gag during genome packaging. Here, we developed functional analysis of RNA structure-sequencing (FARS-seq) to comprehensively identify sequences and structures within the HIV-1 5' untranslated region (UTR) that regulate this critical step. Using FARS-seq, we found nucleotides important for dimerization throughout the HIV-1 5' UTR and identified distinct structural conformations in monomeric and dimeric RNA. In the dimeric RNA, key functional domains, such as stem-loop 1 (SL1), polyadenylation signal (polyA) and primer binding site (PBS), folded into independent structural motifs. In the monomeric RNA, SL1 was reconfigured into long- and short-range base pairings with polyA and PBS, respectively. We show that these interactions disrupt genome packaging, and additionally show that the PBS-SL1 interaction unexpectedly couples the PBS with dimerization and Pr55Gag binding. Altogether, our data provide insights into late stages of HIV-1 life cycle and a mechanistic explanation for the link between RNA dimerization and packaging.
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Affiliation(s)
- Liqing Ye
- grid.498164.6Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, Würzburg, Germany
| | - Anne-Sophie Gribling-Burrer
- grid.498164.6Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, Würzburg, Germany
| | - Patrick Bohn
- grid.498164.6Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, Würzburg, Germany
| | - Anuja Kibe
- grid.498164.6Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, Würzburg, Germany
| | - Charlene Börtlein
- grid.498164.6Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, Würzburg, Germany
| | - Uddhav B. Ambi
- grid.498164.6Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, Würzburg, Germany
| | - Shazeb Ahmad
- grid.498164.6Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, Würzburg, Germany
| | - Marco Olguin-Nava
- grid.498164.6Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, Würzburg, Germany
| | - Maureen Smith
- grid.13652.330000 0001 0940 3744P5 Systems Medicine of Infectious Disease, Robert Koch-Institute, Berlin, Germany
| | - Neva Caliskan
- grid.498164.6Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, Würzburg, Germany ,grid.8379.50000 0001 1958 8658Faculty of Medicine, University of Würzburg, Würzburg, Germany
| | - Max von Kleist
- grid.13652.330000 0001 0940 3744P5 Systems Medicine of Infectious Disease, Robert Koch-Institute, Berlin, Germany
| | - Redmond P. Smyth
- grid.498164.6Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, Würzburg, Germany ,grid.8379.50000 0001 1958 8658Faculty of Medicine, University of Würzburg, Würzburg, Germany
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2
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Song Z, Gremminger T, Singh G, Cheng Y, Li J, Qiu L, Ji J, Lange MJ, Zuo X, Chen SJ, Zou X, Boris-Lawrie K, Heng X. The three-way junction structure of the HIV-1 PBS-segment binds host enzyme important for viral infectivity. Nucleic Acids Res 2021; 49:5925-5942. [PMID: 33978756 PMCID: PMC8191761 DOI: 10.1093/nar/gkab342] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 04/15/2021] [Accepted: 04/19/2021] [Indexed: 12/24/2022] Open
Abstract
HIV-1 reverse transcription initiates at the primer binding site (PBS) in the viral genomic RNA (gRNA). Although the structure of the PBS-segment undergoes substantial rearrangement upon tRNALys3 annealing, the proper folding of the PBS-segment during gRNA packaging is important as it ensures loading of beneficial host factors. DHX9/RNA helicase A (RHA) is recruited to gRNA to enhance the processivity of reverse transcriptase. Because the molecular details of the interactions have yet to be defined, we solved the solution structure of the PBS-segment preferentially bound by RHA. Evidence is provided that PBS-segment adopts a previously undefined adenosine-rich three-way junction structure encompassing the primer activation stem (PAS), tRNA-like element (TLE) and tRNA annealing arm. Disruption of the PBS-segment three-way junction structure diminished reverse transcription products and led to reduced viral infectivity. Because of the existence of the tRNA annealing arm, the TLE and PAS form a bent helical structure that undergoes shape-dependent recognition by RHA double-stranded RNA binding domain 1 (dsRBD1). Mutagenesis and phylogenetic analyses provide evidence for conservation of the PBS-segment three-way junction structure that is preferentially bound by RHA in support of efficient reverse transcription, the hallmark step of HIV-1 replication.
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Affiliation(s)
- Zhenwei Song
- Department of Biochemistry, University of Missouri, Columbia, MO, 65211, USA
| | - Thomas Gremminger
- Department of Biochemistry, University of Missouri, Columbia, MO, 65211, USA
| | - Gatikrushna Singh
- Department of Veterinary and Biomedical Sciences, University of Minnesota, Saint Paul, MN 55108, USA
| | - Yi Cheng
- Department of Biochemistry, University of Missouri, Columbia, MO, 65211, USA
- Department of Physics and Astronomy, University of Missouri, Columbia, MO 65211, USA
- Institute for Data Science and Informatics, University of Missouri, Columbia, MO 65211, USA
| | - Jun Li
- Department of Biochemistry, University of Missouri, Columbia, MO, 65211, USA
- Department of Physics and Astronomy, University of Missouri, Columbia, MO 65211, USA
- Institute for Data Science and Informatics, University of Missouri, Columbia, MO 65211, USA
| | - Liming Qiu
- Department of Biochemistry, University of Missouri, Columbia, MO, 65211, USA
- Department of Physics and Astronomy, University of Missouri, Columbia, MO 65211, USA
- Institute for Data Science and Informatics, University of Missouri, Columbia, MO 65211, USA
- Dalton Cardiovascular Research Center, University Missouri, Columbia, MO 65211, USA
| | - Juan Ji
- Department of Biochemistry, University of Missouri, Columbia, MO, 65211, USA
| | - Margaret J Lange
- Department of Molecular Microbiology and Immunology, University of Missouri, Columbia, MO 65211, USA
| | - Xiaobing Zuo
- X-Ray Science Division, Argonne National Laboratory, Lemont, IL, 60439, USA
| | - Shi-Jie Chen
- Department of Biochemistry, University of Missouri, Columbia, MO, 65211, USA
- Department of Physics and Astronomy, University of Missouri, Columbia, MO 65211, USA
- Institute for Data Science and Informatics, University of Missouri, Columbia, MO 65211, USA
| | - Xiaoqin Zou
- Department of Biochemistry, University of Missouri, Columbia, MO, 65211, USA
- Department of Physics and Astronomy, University of Missouri, Columbia, MO 65211, USA
- Institute for Data Science and Informatics, University of Missouri, Columbia, MO 65211, USA
- Dalton Cardiovascular Research Center, University Missouri, Columbia, MO 65211, USA
| | - Kathleen Boris-Lawrie
- Department of Veterinary and Biomedical Sciences, University of Minnesota, Saint Paul, MN 55108, USA
| | - Xiao Heng
- Department of Biochemistry, University of Missouri, Columbia, MO, 65211, USA
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3
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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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4
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Abstract
Here we have directly visualized conformational changes in the 5′UTR of the HIV-1 genome using single-molecule fluorescence techniques. We find that the monomeric 5′UTR can spontaneously transition between two conformations, which have distinct intramolecular base pairing. One of the observed conformations is competent for dimerization with a second 5′UTR molecule. Our results are consistent with a model in which dimerization initiates by way of localized intermolecular kissing-loop base pairing, which is promoted by tRNA primer annealing. The intermolecular interface then extends, giving rise to the putative extended dimer, which is stabilized by HIV-1 NC. Thus, the 5′UTR is intrinsically dynamic, and both viral and host factors play a role in modulating the RNA conformation and dynamics. The highly conserved 5′ untranslated region (5′UTR) of the HIV-1 RNA genome is central to the regulation of virus replication. NMR and biochemical experiments support a model in which the 5′UTR can transition between at least two conformational states. In one state the genome remains a monomer, as the palindromic dimerization initiation site (DIS) is sequestered via base pairing to upstream sequences. In the second state, the DIS is exposed, and the genome is competent for kissing loop dimerization and packaging into assembling virions where an extended dimer is formed. According to this model the conformation of the 5′UTR determines the fate of the genome. In this work, the dynamics of this proposed conformational switch and the factors that regulate it were probed using multiple single-molecule and in-gel ensemble FRET assays. Our results show that the HIV-1 5′UTR intrinsically samples conformations that are stabilized by both viral and host factor binding. Annealing of tRNALys3, the primer for initiation of reverse transcription, can promote the kissing dimer but not the extended dimer. In contrast, HIV-1 nucleocapsid (NC) promotes formation of the extended dimer in both the absence and presence of tRNALys3. Our data are consistent with an ordered series of events that involves primer annealing, genome dimerization, and virion assembly.
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5
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Boeras I, Song Z, Moran A, Franklin J, Brown WC, Johnson M, Boris-Lawrie K, Heng X. DHX9/RHA Binding to the PBS-Segment of the Genomic RNA during HIV-1 Assembly Bolsters Virion Infectivity. J Mol Biol 2016; 428:2418-2429. [PMID: 27107641 DOI: 10.1016/j.jmb.2016.04.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2016] [Revised: 04/04/2016] [Accepted: 04/07/2016] [Indexed: 12/28/2022]
Abstract
Cellular RNA-binding proteins incorporated into virions during human immunodeficiency virus type 1 (HIV-1) assembly promote the replication efficiency of progeny virions. Despite its critical role in bolstering virion infectivity, the molecular basis for the incorporation of DHX9/RNA helicase A (RHA) to virions remains unclear. Here, cell-based experiments demonstrate that the truncation of segments of the HIV-1 5'-untranslated region (5'-UTR) distinct from the core encapsidation sequence eliminated virion incorporation of RHA, indicating that RHA recruitment is mediated by specific interactions with the HIV-1 5'-UTR. In agreement with biological data, isothermal titration calorimetry determined that the dimer conformation of the 5'-UTR binds one RHA molecule per RNA strand, and the interaction is independent of nucleocapsid protein binding. NMR spectra employing a deuterium-labeling approach enabled resolution of the dimeric 5'-UTR in complex with the RHA N-terminal domain. The structure of the large molecular mass complex was dependent on RHA binding to a double-stranded region of the primer binding site (PBS)-segment of the 5'-UTR. A single A-to-C substitution was sufficient to disrupt biophysical conformation and attenuate virion infectivity in cell-based assays. Taken together, our studies demonstrate the structural basis for HIV-1 genomic RNA to recruit beneficial cellular cofactor to virions. The support of progeny virion infectivity by RHA is attributable to structure-dependent binding at the PBS-segment of the HIV-1 5'-UTR during virus assembly.
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Affiliation(s)
- Ioana Boeras
- Department of Veterinary and Biomedical Sciences, University of Minnesota, Saint Paul, MN 55108, USA
| | - Zhenwei Song
- Department of Biochemistry, University of Missouri, Columbia, MO 65211, USA
| | - Andrew Moran
- Department of Biochemistry, University of Missouri, Columbia, MO 65211, USA
| | - Jarryd Franklin
- Department of Biochemistry, University of Missouri, Columbia, MO 65211, USA
| | - William Clay Brown
- Center for Structural Biology, Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Marc Johnson
- Department of Molecular Microbiology and Immunology, University of Missouri, Columbia, MO 65211, USA
| | - Kathleen Boris-Lawrie
- Department of Veterinary and Biomedical Sciences, University of Minnesota, Saint Paul, MN 55108, USA.
| | - Xiao Heng
- Department of Biochemistry, University of Missouri, Columbia, MO 65211, USA.
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6
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Le Grice SFJ. Targeting the HIV RNA genome: high-hanging fruit only needs a longer ladder. Curr Top Microbiol Immunol 2015; 389:147-69. [PMID: 25735922 PMCID: PMC7120518 DOI: 10.1007/82_2015_434] [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] [Indexed: 03/17/2023]
Abstract
Small molecules targeting the enzymes responsible for human immunodeficiency virus (HIV) maturation, DNA synthesis and its subsequent chromosomal integration as ribonucleotide-free double-stranded DNA remain the mainstay of combination antiretroviral therapy. For infected individuals harboring drug-susceptible virus, this approach has afforded complete or near-complete viral suppression. However, in the absence of a curative strategy, the predictable emergence of drug-resistant variants requires continued development of improved antiviral strategies, inherent to which is the necessity of identifying novel targets. Regulatory elements that mediate transcription, translation, nucleocytoplasmic transport, dimerization, packaging and reverse transcription of the (+) strand RNA genome should now be considered viable targets for small molecule, peptide- and oligonucleotide-based therapeutics. Where target specificity and cellular penetration and toxicity have been the primary obstacle to successful “macromolecule therapeutics”, this chapter summarizes (a) novel approaches targeting RNA motifs whose three-dimensional structure is critical for biological function and consequently may be less prone to resistance-conferring mutations and (b) improved methods for delivery.
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Affiliation(s)
- Stuart F J Le Grice
- RT Biochemistry Section, Basic Research Laboratory, National Cancer Institute, Frederick, MD, 21702, USA,
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7
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Kolomiets IN, Zarudnaya MI, Potyahaylo AL, Hovorun DM. Structural insight into HIV-1 reverse transcription initiation in MAL-like templates (CRF01_AE, subtype G and CRF02_AG). J Biomol Struct Dyn 2014; 33:418-33. [DOI: 10.1080/07391102.2014.884938] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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8
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Godet J, Boudier C, Humbert N, Ivanyi-Nagy R, Darlix JL, Mély Y. Comparative nucleic acid chaperone properties of the nucleocapsid protein NCp7 and Tat protein of HIV-1. Virus Res 2012; 169:349-60. [PMID: 22743066 PMCID: PMC7114403 DOI: 10.1016/j.virusres.2012.06.021] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Revised: 06/18/2012] [Accepted: 06/19/2012] [Indexed: 10/28/2022]
Abstract
RNA chaperones are proteins able to rearrange nucleic acid structures towards their most stable conformations. In retroviruses, the reverse transcription of the viral RNA requires multiple and complex nucleic acid rearrangements that need to be chaperoned. HIV-1 has evolved different viral-encoded proteins with chaperone activity, notably Tat and the well described nucleocapsid protein NCp7. We propose here an overview of the recent reports that examine and compare the nucleic acid chaperone properties of Tat and NCp7 during reverse transcription to illustrate the variety of mechanisms of action of the nucleic acid chaperone proteins.
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Affiliation(s)
- Julien Godet
- Laboratoire de Biophotonique et Pharmacologie, Faculté de Pharmacie, UMR 7213 CNRS, Université de Strasbourg, 67401 Illkirch, France
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9
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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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10
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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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11
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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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12
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Ooms M, Cupac D, Abbink TEM, Huthoff H, Berkhout B. The availability of the primer activation signal (PAS) affects the efficiency of HIV-1 reverse transcription initiation. Nucleic Acids Res 2007; 35:1649-59. [PMID: 17308346 PMCID: PMC1865047 DOI: 10.1093/nar/gkm046] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Initiation of reverse transcription of a retroviral RNA genome is strictly regulated. The tRNA primer binds to the primer binding site (PBS), and subsequent priming is triggered by the primer activation signal (PAS) that also pairs with the tRNA. We observed that in vitro reverse transcription initiation of the HIV-1 leader RNA varies in efficiency among 3′-end truncated transcripts, despite the presence of both PBS and PAS motifs. As the HIV-1 leader RNA can adopt two different foldings, we investigated if the conformational state of the transcripts did influence the efficiency of reverse transcription initiation. However, mutant transcripts that exclusively fold one or the other structure were similarly active, thereby excluding the possibility of regulation of reverse transcription initiation by the structure riboswitch. We next set out to determine the availability of the PAS element. This sequence motif enhances the efficiency of reverse transcription initiation, but its activity is regulated because the PAS motif is initially base paired within the wild-type template. We measured that the initiation efficiency on different templates correlates directly with accessibility of the PAS motif. Furthermore, changes in PAS are critical to facilitate a primer-switch to a new tRNA species, demonstrating the importance of this enhancer element.
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Affiliation(s)
| | | | | | | | - Ben Berkhout
- *To whom correspondence should be addressed. +31 205 664 822+31 206 916 531
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13
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Kasprzak W, Bindewald E, Shapiro BA. Structural polymorphism of the HIV-1 leader region explored by computational methods. Nucleic Acids Res 2005; 33:7151-63. [PMID: 16371347 PMCID: PMC1322270 DOI: 10.1093/nar/gki1015] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Experimental studies revealed that the elements of the human immunodeficiency virus type 1 (HIV-1) 5′-untranslated leader region (5′-UTR) can fold in vitro into two alternative conformations, branched (BMH) and ‘linearized’ (LDI) and switch between them to achieve different functionality. In this study we computationally explored in detail, with our massively parallel genetic algorithm (MPGAfold), the propensity of 13 HIV-1 5′-UTRs to fold into the BMH and the LDI conformation types. Besides the BMH conformations these results predict the existence of two functionally equivalent types of LDI conformations. One is similar to what has been shown in vitro to exist in HIV-1 LAI, the other is a novel conformation exemplified by HIV-1 MAL long-distance interactions. These novel MPGAfold results are further corroborated by a consensus probability matrix algorithm applied to a set of 155 HIV-1 sequences. We also have determined in detail the impact of various strain mutations, domain sizes and folds of elongating sequences simulating folding during transcription on HIV-1 RNA secondary structure folding dynamics.
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Affiliation(s)
| | | | - Bruce A. Shapiro
- Center for Cancer Research Nanobiology Program, National Cancer InstituteBuilding 469, Room 150, NCI-Frederick, Frederick, MD 21702, USA
- To whom correspondence should be addressed. Tel: +1 301 846 5536; Fax: +1 301 846 5598;
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14
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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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