1
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Chakrabortty A, Mondal S, Bandyopadhyay S. Conformational Properties of Poly(A)-Binding Protein Complexed with Poly(A) RNA. J Phys Chem B 2024; 128:6449-6462. [PMID: 38941243 DOI: 10.1021/acs.jpcb.4c00704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/30/2024]
Abstract
Microscopic understanding of protein-RNA interactions is important for different biological activities, such as RNA transport, translation, splicing, silencing, etc. Polyadenine (Poly(A)) binding proteins (PABPs) make up a class of regulatory proteins that play critical roles in protecting the poly(A) tails of cellular mRNAs from nuclease degradation. In this work, we performed molecular dynamics simulations to investigate the conformational modifications of human PABP protein and poly(A) RNA that occur during complexation. It is demonstrated that the intermediate linker domain of the protein transforms from a disordered coil-like structure to a helical form during the recognition process, leading to the formation of the complex. On the other hand, disordered collapsed coil-like RNA on complexation has been found to transform into a rigid extended conformation. Importantly, the binding free energy calculation showed that the thermodynamic stability of the complex is primarily guided by favorable hydrophobic interactions between the protein and the RNA.
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Affiliation(s)
- Arun Chakrabortty
- Centre for Computational and Data Sciences, Indian Institute of Technology Kharagpur, Kharagpur - 721302, India
| | - Sandip Mondal
- Molecular Modeling Laboratory, Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur - 721302, India
| | - Sanjoy Bandyopadhyay
- Molecular Modeling Laboratory, Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur - 721302, India
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2
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Kamba K, Wan L, Unzai S, Morishita R, Takaori-Kondo A, Nagata T, Katahira M. Direct inhibition of human APOBEC3 deaminases by HIV-1 Vif independent of the proteolysis pathway. Biophys J 2024; 123:294-306. [PMID: 38115583 PMCID: PMC10870137 DOI: 10.1016/j.bpj.2023.12.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 12/01/2023] [Accepted: 12/14/2023] [Indexed: 12/21/2023] Open
Abstract
HIV-1 Vif is known to counteract the antiviral activity of human apolipoprotein B mRNA-editing catalytic polypeptide-like (A3), a cytidine deaminase, in various ways. However, the precise mechanism behind this interaction has remained elusive. Within infected cells, Vif forms a complex called VβBCC, comprising CBFβ and the components of E3 ubiquitin ligase, Elongin B, Elongin C, and Cullin5. Together with the ubiquitin-conjugating enzyme, VβBCC induces ubiquitination-mediated proteasomal degradation of A3. However, Vif exhibits additional counteractive effects. In this study, we elucidate that VβBCC inhibits deamination by A3G, A3F, and A3B independently of proteasomal degradation. Surprisingly, we discovered that this inhibition for A3G is directly attributed to the interaction between VβBCC and the C-terminal domain of A3G. Previously, it was believed that Vif did not interact with the C-terminal domain. Our findings suggest that inhibiting the interaction between VβBCC and the C-terminal domain, as well as the N-terminal domain known to be targeted for ubiquitination, of A3G may be needed to prevent counteraction by Vif.
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Affiliation(s)
- Keisuke Kamba
- Institute of Advanced Energy, Kyoto University, Uji, Kyoto, Japan
| | - Li Wan
- Institute of Advanced Energy, Kyoto University, Uji, Kyoto, Japan; Graduate School of Energy Science, Kyoto University, Uji, Kyoto, Japan
| | - Satoru Unzai
- Department of Frontier Bioscience, Hosei University, Koganei, Tokyo, Japan
| | - Ryo Morishita
- CellFree Sciences Co., Ltd., Matsuyama, Ehime, Japan
| | - Akifumi Takaori-Kondo
- Department of Hematology and Oncology Graduate School of Medicine, Kyoto University, Sakyo-ku, Kyoto, Japan
| | - Takashi Nagata
- Institute of Advanced Energy, Kyoto University, Uji, Kyoto, Japan; Graduate School of Energy Science, Kyoto University, Uji, Kyoto, Japan.
| | - Masato Katahira
- Institute of Advanced Energy, Kyoto University, Uji, Kyoto, Japan; Graduate School of Energy Science, Kyoto University, Uji, Kyoto, Japan.
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3
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Cantara WA, Pathirage C, Hatterschide J, Olson ED, Musier-Forsyth K. Phosphomimetic S207D Lysyl-tRNA Synthetase Binds HIV-1 5'UTR in an Open Conformation and Increases RNA Dynamics. Viruses 2022; 14:1556. [PMID: 35891536 PMCID: PMC9315659 DOI: 10.3390/v14071556] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 07/08/2022] [Accepted: 07/13/2022] [Indexed: 01/25/2023] Open
Abstract
Interactions between lysyl-tRNA synthetase (LysRS) and HIV-1 Gag facilitate selective packaging of the HIV-1 reverse transcription primer, tRNALys3. During HIV-1 infection, LysRS is phosphorylated at S207, released from a multi-aminoacyl-tRNA synthetase complex and packaged into progeny virions. LysRS is critical for proper targeting of tRNALys3 to the primer-binding site (PBS) by specifically binding a PBS-adjacent tRNA-like element (TLE), which promotes release of the tRNA proximal to the PBS. However, whether LysRS phosphorylation plays a role in this process remains unknown. Here, we used a combination of binding assays, RNA chemical probing, and small-angle X-ray scattering to show that both wild-type (WT) and a phosphomimetic S207D LysRS mutant bind similarly to the HIV-1 genomic RNA (gRNA) 5'UTR via direct interactions with the TLE and stem loop 1 (SL1) and have a modest preference for binding dimeric gRNA. Unlike WT, S207D LysRS bound in an open conformation and increased the dynamics of both the PBS region and SL1. A new working model is proposed wherein a dimeric phosphorylated LysRS/tRNA complex binds to a gRNA dimer to facilitate tRNA primer release and placement onto the PBS. Future anti-viral strategies that prevent this host factor-gRNA interaction are envisioned.
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Affiliation(s)
- William A. Cantara
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA; (C.P.); (J.H.); (E.D.O.)
- Center for Retrovirus Research, The Ohio State University, Columbus, OH 43210, USA
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Chathuri Pathirage
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA; (C.P.); (J.H.); (E.D.O.)
- Center for Retrovirus Research, The Ohio State University, Columbus, OH 43210, USA
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
- Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA
| | - Joshua Hatterschide
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA; (C.P.); (J.H.); (E.D.O.)
- Center for Retrovirus Research, The Ohio State University, Columbus, OH 43210, USA
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Erik D. Olson
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA; (C.P.); (J.H.); (E.D.O.)
- Center for Retrovirus Research, The Ohio State University, Columbus, OH 43210, USA
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
- Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA
| | - Karin Musier-Forsyth
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA; (C.P.); (J.H.); (E.D.O.)
- Center for Retrovirus Research, The Ohio State University, Columbus, OH 43210, USA
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
- Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA
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4
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Bacterial Transcriptional Regulators: A Road Map for Functional, Structural, and Biophysical Characterization. Int J Mol Sci 2022; 23:ijms23042179. [PMID: 35216300 PMCID: PMC8879271 DOI: 10.3390/ijms23042179] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 02/11/2022] [Accepted: 02/11/2022] [Indexed: 12/12/2022] Open
Abstract
The different niches through which bacteria move during their life cycle require a fast response to the many environmental queues they encounter. The sensing of these stimuli and their correct response is driven primarily by transcriptional regulators. This kind of protein is involved in sensing a wide array of chemical species, a process that ultimately leads to the regulation of gene transcription. The allosteric-coupling mechanism of sensing and regulation is a central aspect of biological systems and has become an important field of research during the last decades. In this review, we summarize the state-of-the-art techniques applied to unravel these complex mechanisms. We introduce a roadmap that may serve for experimental design, depending on the answers we seek and the initial information we have about the system of study. We also provide information on databases containing available structural information on each family of transcriptional regulators. Finally, we discuss the recent results of research about the allosteric mechanisms of sensing and regulation involving many transcriptional regulators of interest, highlighting multipronged strategies and novel experimental techniques. The aim of the experiments discussed here was to provide a better understanding at a molecular level of how bacteria adapt to the different environmental threats they face.
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5
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Sumner C, Kotani O, Liu S, Musier-Forsyth K, Sato H, Ono A. Molecular Determinants in tRNA D-arm Required for Inhibition of HIV-1 Gag Membrane Binding. J Mol Biol 2022; 434:167390. [PMID: 34883117 PMCID: PMC8752508 DOI: 10.1016/j.jmb.2021.167390] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2021] [Revised: 11/23/2021] [Accepted: 11/30/2021] [Indexed: 02/01/2023]
Abstract
Plasma-membrane-specific localization of Gag, an essential step in HIV-1 particle assembly, is regulated by the interaction of the Gag MA domain with PI(4,5)P2 and tRNA-mediated inhibition of non-specific or premature membrane binding. Different tRNAs inhibit PI(4,5)P2-independent membrane binding to varying degrees in vitro; however, the structural determinants for this difference remain unknown. Here we demonstrate that membrane binding of full-length Gag synthesized in vitro using reticulocyte lysates is inhibited when RNAs that contain the anticodon arm of tRNAPro, but not that of tRNALys3, are added exogenously. In contrast, in the context of a liposome binding assay in which the effects of tRNAs on purified MA were tested, full-length tRNALys3 showed greater inhibition of MA membrane binding than full-length tRNAPro. While transplantation of the D loop sequence of tRNALys3 into tRNAPro resulted in a modest increase in the inhibitory effect relative to WT tRNAPro, replacing the entire D arm sequence with that of tRNALys3 was necessary to confer the full inhibitory effects upon tRNAPro. Together, these results demonstrate that the D arm of tRNALys3 is a major determinant of strong inhibition of MA membrane binding and that this inhibitory effect requires not only the D loop, which was recently reported to contact the MA highly basic region, but the loop sequence in the context of the D arm structure.
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Affiliation(s)
- Christopher Sumner
- Dept. of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, United States
| | - Osamu Kotani
- Center for Pathogen Genomics, National Institute of Infectious Diseases, Tokyo, Japan
| | - Shuohui Liu
- Dept. of Chemistry and Biochemistry, Center for Retrovirus Research, and Center for RNA Biology, The Ohio State University, Columbus, OH, United States
| | - Karin Musier-Forsyth
- Dept. of Chemistry and Biochemistry, Center for Retrovirus Research, and Center for RNA Biology, The Ohio State University, Columbus, OH, United States
| | - Hironori Sato
- Center for Pathogen Genomics, National Institute of Infectious Diseases, Tokyo, Japan
| | - Akira Ono
- Dept. of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, United States
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6
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Jin D, Wek SA, Kudlapur NT, Cantara WA, Bakhtina M, Wek RC, Musier-Forsyth K. Disease-associated mutations in a bifunctional aminoacyl-tRNA synthetase gene elicit the integrated stress response. J Biol Chem 2021; 297:101203. [PMID: 34537243 PMCID: PMC8511952 DOI: 10.1016/j.jbc.2021.101203] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 09/01/2021] [Accepted: 09/03/2021] [Indexed: 12/20/2022] Open
Abstract
Aminoacyl-tRNA synthetases (ARSs) catalyze the charging of specific amino acids onto cognate tRNAs, an essential process for protein synthesis. Mutations in ARSs are frequently associated with a variety of human diseases. The human EPRS1 gene encodes a bifunctional glutamyl-prolyl-tRNA synthetase (EPRS) with two catalytic cores and appended domains that contribute to nontranslational functions. In this study, we report compound heterozygous mutations in EPRS1, which lead to amino acid substitutions P14R and E205G in two patients with diabetes and bone diseases. While neither mutation affects tRNA binding or association of EPRS with the multisynthetase complex, E205G in the glutamyl-tRNA synthetase (ERS) region of EPRS is defective in amino acid activation and tRNAGlu charging. The P14R mutation induces a conformational change and altered tRNA charging kinetics in vitro. We propose that the altered catalytic activity and conformational changes in the EPRS variants sensitize patient cells to stress, triggering an increased integrated stress response (ISR) that diminishes cell viability. Indeed, patient-derived cells expressing the compound heterozygous EPRS show heightened induction of the ISR, suggestive of disruptions in protein homeostasis. These results have important implications for understanding ARS-associated human disease mechanisms and development of new therapeutics.
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Affiliation(s)
- Danni Jin
- Department of Chemistry and Biochemistry, Center for RNA Biology, The Ohio State University, Columbus Ohio, USA
| | - Sheree A Wek
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis Indiana, USA
| | - Nathan T Kudlapur
- Department of Chemistry and Biochemistry, Center for RNA Biology, The Ohio State University, Columbus Ohio, USA
| | - William A Cantara
- Department of Chemistry and Biochemistry, Center for RNA Biology, The Ohio State University, Columbus Ohio, USA
| | - Marina Bakhtina
- Department of Chemistry and Biochemistry, Center for RNA Biology, The Ohio State University, Columbus Ohio, USA
| | - Ronald C Wek
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis Indiana, USA
| | - Karin Musier-Forsyth
- Department of Chemistry and Biochemistry, Center for RNA Biology, The Ohio State University, Columbus Ohio, USA.
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7
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Liu S, Refaei M, Liu S, Decker A, Hinerman JM, Herr AB, Howell M, Musier-Forsyth K, Tsang P. Hairpin RNA-induced conformational change of a eukaryotic-specific lysyl-tRNA synthetase extension and role of adjacent anticodon-binding domain. J Biol Chem 2020; 295:12071-12085. [PMID: 32611767 PMCID: PMC7443506 DOI: 10.1074/jbc.ra120.013852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Revised: 06/26/2020] [Indexed: 11/06/2022] Open
Abstract
Human lysyl-tRNA synthetase (hLysRS) is essential for aminoacylation of tRNALys Higher eukaryotic LysRSs possess an N-terminal extension (Nterm) previously shown to facilitate high-affinity tRNA binding and aminoacylation. This eukaryote-specific appended domain also plays a critical role in hLysRS nuclear localization, thus facilitating noncanonical functions of hLysRS. The structure is intrinsically disordered and therefore remains poorly characterized. Findings of previous studies are consistent with the Nterm domain undergoing a conformational transition to an ordered structure upon nucleic acid binding. In this study, we used NMR to investigate how the type of RNA, as well as the presence of the adjacent anticodon-binding domain (ACB), influences the Nterm conformation. To explore the latter, we used sortase A ligation to produce a segmentally labeled tandem-domain protein, Nterm-ACB. In the absence of RNA, Nterm remained disordered regardless of ACB attachment. Both alone and when attached to ACB, Nterm structure remained unaffected by titration with single-stranded RNAs. The central region of the Nterm domain adopted α-helical structure upon titration of Nterm and Nterm-ACB with RNA hairpins containing double-stranded regions. Nterm binding to the RNA hairpins resulted in CD spectral shifts consistent with an induced helical structure. NMR and fluorescence anisotropy revealed that Nterm binding to hairpin RNAs is weak but that the binding affinity increases significantly upon covalent attachment to ACB. We conclude that the ACB domain facilitates induced-fit conformational changes and confers high-affinity RNA hairpin binding, which may be advantageous for functional interactions of LysRS with a variety of different binding partners.
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Affiliation(s)
- Sheng Liu
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio, USA
| | - Maryanne Refaei
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio, USA
| | - Shuohui Liu
- Department of Chemistry and Biochemistry, Center for RNA Biology, Ohio State University, Columbus, Ohio, USA
| | - Aaron Decker
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio, USA
| | - Jennifer M. Hinerman
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
- Division of Immunobiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Andrew B. Herr
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
- Division of Immunobiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Mike Howell
- Protein Express, Inc., Cincinnati, Ohio, USA
| | - Karin Musier-Forsyth
- Department of Chemistry and Biochemistry, Center for RNA Biology, Ohio State University, Columbus, Ohio, USA
| | - Pearl Tsang
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio, USA
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8
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Sarni S, Biswas B, Liu S, Olson ED, Kitzrow JP, Rein A, Wysocki VH, Musier-Forsyth K. HIV-1 Gag protein with or without p6 specifically dimerizes on the viral RNA packaging signal. J Biol Chem 2020; 295:14391-14401. [PMID: 32817318 DOI: 10.1074/jbc.ra120.014835] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 08/10/2020] [Indexed: 02/04/2023] Open
Abstract
The HIV-1 Gag protein is responsible for genomic RNA (gRNA) packaging and immature viral particle assembly. Although the presence of gRNA in virions is required for viral infectivity, in its absence, Gag can assemble around cellular RNAs and form particles resembling gRNA-containing particles. When gRNA is expressed, it is selectively packaged despite the presence of excess host RNA, but how it is selectively packaged is not understood. Specific recognition of a gRNA packaging signal (Psi) has been proposed to stimulate the efficient nucleation of viral assembly. However, the heterogeneity of Gag-RNA interactions renders capturing this transient nucleation complex using traditional structural biology approaches challenging. Here, we used native MS to investigate RNA binding of wild-type (WT) Gag and Gag lacking the p6 domain (GagΔp6). Both proteins bind to Psi RNA primarily as dimers, but to a control RNA primarily as monomers. The dimeric complexes on Psi RNA require an intact dimer interface within Gag. GagΔp6 binds to Psi RNA with high specificity in vitro and also selectively packages gRNA in particles produced in mammalian cells. These studies provide direct support for the idea that Gag binding to Psi specifically promotes nucleation of Gag-Gag interactions at the early stages of immature viral particle assembly in a p6-independent manner.
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Affiliation(s)
- Samantha Sarni
- Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio, USA.,Resource for Native Mass Spectrometry Guided Structural Biology, The Ohio State University, Columbus, Ohio, USA.,Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA
| | - Banhi Biswas
- HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, Frederick, Maryland, USA
| | - Shuohui Liu
- Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA.,Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio, USA.,Center for Retrovirus Research, The Ohio State University, Columbus, Ohio, USA
| | - Erik D Olson
- Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio, USA.,Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA.,Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio, USA.,Center for Retrovirus Research, The Ohio State University, Columbus, Ohio, USA
| | - Jonathan P Kitzrow
- Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio, USA.,Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA.,Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio, USA.,Center for Retrovirus Research, The Ohio State University, Columbus, Ohio, USA
| | - Alan Rein
- HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, Frederick, Maryland, USA
| | - Vicki H Wysocki
- Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio, USA .,Resource for Native Mass Spectrometry Guided Structural Biology, The Ohio State University, Columbus, Ohio, USA.,Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA.,Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio, USA
| | - Karin Musier-Forsyth
- Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio, USA .,Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA.,Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio, USA.,Center for Retrovirus Research, The Ohio State University, Columbus, Ohio, USA
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9
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Rous Sarcoma Virus Genomic RNA Dimerization Capability In Vitro Is Not a Prerequisite for Viral Infectivity. Viruses 2020; 12:v12050568. [PMID: 32455905 PMCID: PMC7291142 DOI: 10.3390/v12050568] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 05/19/2020] [Accepted: 05/20/2020] [Indexed: 12/29/2022] Open
Abstract
Retroviruses package their full-length, dimeric genomic RNA (gRNA) via specific interactions between the Gag polyprotein and a “Ψ” packaging signal located in the gRNA 5′-UTR. Rous sarcoma virus (RSV) gRNA has a contiguous, well-defined Ψ element, that directs the packaging of heterologous RNAs efficiently. The simplicity of RSV Ψ makes it an informative model to examine the mechanism of retroviral gRNA packaging, which is incompletely understood. Little is known about the structure of dimerization initiation sites or specific Gag interaction sites of RSV gRNA. Using selective 2′-hydroxyl acylation analyzed by primer extension (SHAPE), we probed the secondary structure of the entire RSV 5′-leader RNA for the first time. We identified a putative bipartite dimerization initiation signal (DIS), and mutation of both sites was required to significantly reduce dimerization in vitro. These mutations failed to reduce viral replication, suggesting that in vitro dimerization results do not strictly correlate with in vivo infectivity, possibly due to additional RNA interactions that maintain the dimers in cells. UV crosslinking-coupled SHAPE (XL-SHAPE) was next used to determine Gag-induced RNA conformational changes, revealing G218 as a critical Gag contact site. Overall, our results suggest that disruption of either of the DIS sequences does not reduce virus replication and reveal specific sites of Gag–RNA interactions.
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10
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Antonucci JM, Kim SH, St Gelais C, Bonifati S, Li TW, Buzovetsky O, Knecht KM, Duchon AA, Xiong Y, Musier-Forsyth K, Wu L. SAMHD1 Impairs HIV-1 Gene Expression and Negatively Modulates Reactivation of Viral Latency in CD4 + T Cells. J Virol 2018; 92:e00292-18. [PMID: 29793958 PMCID: PMC6052313 DOI: 10.1128/jvi.00292-18] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Accepted: 05/15/2018] [Indexed: 11/20/2022] Open
Abstract
Sterile alpha motif and HD domain-containing protein 1 (SAMHD1) restricts human immunodeficiency virus type 1 (HIV-1) replication in nondividing cells by degrading intracellular deoxynucleoside triphosphates (dNTPs). SAMHD1 is highly expressed in resting CD4+ T cells, which are important for the HIV-1 reservoir and viral latency; however, whether SAMHD1 affects HIV-1 latency is unknown. Recombinant SAMHD1 binds HIV-1 DNA or RNA fragments in vitro, but the function of this binding remains unclear. Here we investigate the effect of SAMHD1 on HIV-1 gene expression and reactivation of viral latency. We found that endogenous SAMHD1 impaired HIV-1 long terminal repeat (LTR) activity in monocytic THP-1 cells and HIV-1 reactivation in latently infected primary CD4+ T cells. Overexpression of wild-type (WT) SAMHD1 suppressed HIV-1 LTR-driven gene expression at a transcriptional level. Tat coexpression abrogated SAMHD1-mediated suppression of HIV-1 LTR-driven luciferase expression. SAMHD1 overexpression also suppressed the LTR activity of human T-cell leukemia virus type 1 (HTLV-1), but not that of murine leukemia virus (MLV), suggesting specific suppression of retroviral LTR-driven gene expression. WT SAMHD1 bound to proviral DNA and impaired reactivation of HIV-1 gene expression in latently infected J-Lat cells. In contrast, a nonphosphorylated mutant (T592A) and a dNTP triphosphohydrolase (dNTPase) inactive mutant (H206D R207N [HD/RN]) of SAMHD1 failed to efficiently suppress HIV-1 LTR-driven gene expression and reactivation of latent virus. Purified recombinant WT SAMHD1, but not the T592A and HD/RN mutants, bound to fragments of the HIV-1 LTR in vitro These findings suggest that SAMHD1-mediated suppression of HIV-1 LTR-driven gene expression potentially regulates viral latency in CD4+ T cells.IMPORTANCE A critical barrier to developing a cure for HIV-1 infection is the long-lived viral reservoir that exists in resting CD4+ T cells, the main targets of HIV-1. The viral reservoir is maintained through a variety of mechanisms, including regulation of the HIV-1 LTR promoter. The host protein SAMHD1 restricts HIV-1 replication in nondividing cells, but its role in HIV-1 latency remains unknown. Here we report a new function of SAMHD1 in regulating HIV-1 latency. We found that SAMHD1 suppressed HIV-1 LTR promoter-driven gene expression and reactivation of viral latency in cell lines and primary CD4+ T cells. Furthermore, SAMHD1 bound to the HIV-1 LTR in vitro and in a latently infected CD4+ T-cell line, suggesting that the binding may negatively modulate reactivation of HIV-1 latency. Our findings indicate a novel role for SAMHD1 in regulating HIV-1 latency, which enhances our understanding of the mechanisms regulating proviral gene expression in CD4+ T cells.
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Affiliation(s)
- Jenna M Antonucci
- Center for Retrovirus Research, The Ohio State University, Columbus, Ohio, USA
- Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio, USA
- Department of Microbiology, The Ohio State University, Columbus, Ohio, USA
| | - Sun Hee Kim
- Center for Retrovirus Research, The Ohio State University, Columbus, Ohio, USA
- Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio, USA
| | - Corine St Gelais
- Center for Retrovirus Research, The Ohio State University, Columbus, Ohio, USA
- Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio, USA
| | - Serena Bonifati
- Center for Retrovirus Research, The Ohio State University, Columbus, Ohio, USA
- Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio, USA
| | - Tai-Wei Li
- Center for Retrovirus Research, The Ohio State University, Columbus, Ohio, USA
- Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio, USA
| | - Olga Buzovetsky
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA
| | - Kirsten M Knecht
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA
| | - Alice A Duchon
- Center for Retrovirus Research, The Ohio State University, Columbus, Ohio, USA
- Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio, USA
| | - Yong Xiong
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA
| | - Karin Musier-Forsyth
- Center for Retrovirus Research, The Ohio State University, Columbus, Ohio, USA
- Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio, USA
| | - Li Wu
- Center for Retrovirus Research, The Ohio State University, Columbus, Ohio, USA
- Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio, USA
- Department of Microbiology, The Ohio State University, Columbus, Ohio, USA
- Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA
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11
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Olson ED, Musier-Forsyth K. Retroviral Gag protein-RNA interactions: Implications for specific genomic RNA packaging and virion assembly. Semin Cell Dev Biol 2018; 86:129-139. [PMID: 29580971 DOI: 10.1016/j.semcdb.2018.03.015] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 03/09/2018] [Accepted: 03/22/2018] [Indexed: 02/04/2023]
Abstract
Retroviral Gag proteins are responsible for coordinating many aspects of virion assembly. Gag possesses two distinct nucleic acid binding domains, matrix (MA) and nucleocapsid (NC). One of the critical functions of Gag is to specifically recognize, bind, and package the retroviral genomic RNA (gRNA) into assembling virions. Gag interactions with cellular RNAs have also been shown to regulate aspects of assembly. Recent results have shed light on the role of MA and NC domain interactions with nucleic acids, and how they jointly function to ensure packaging of the retroviral gRNA. Here, we will review the literature regarding RNA interactions with NC, MA, as well as overall mechanisms employed by Gag to interact with RNA. The discussion focuses on human immunodeficiency virus type-1, but other retroviruses will also be discussed. A model is presented combining all of the available data summarizing the various factors and layers of selection Gag employs to ensure specific gRNA packaging and correct virion assembly.
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Affiliation(s)
- Erik D Olson
- Department of Chemistry and Biochemistry, Center for RNA Biology, and Center for Retrovirus Research, Ohio State University, Columbus, OH, 43210, USA
| | - Karin Musier-Forsyth
- Department of Chemistry and Biochemistry, Center for RNA Biology, and Center for Retrovirus Research, Ohio State University, Columbus, OH, 43210, USA.
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12
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Comandur R, Olson ED, Musier-Forsyth K. Conservation of tRNA mimicry in the 5'-untranslated region of distinct HIV-1 subtypes. RNA (NEW YORK, N.Y.) 2017; 23:1850-1859. [PMID: 28860303 PMCID: PMC5689005 DOI: 10.1261/rna.062182.117] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Accepted: 08/25/2017] [Indexed: 06/07/2023]
Abstract
Human tRNALys3 serves as the primer for reverse transcription in human immunodeficiency virus type-1 (HIV-1) and anneals to the complementary primer binding site (PBS) in the genome. All tRNALys isoacceptors interact with human lysyl-tRNA synthetase (hLysRS) and are selectively packaged into virions. tRNALys3 must be released from hLysRS in order to anneal to the PBS, and this process is proposed to be facilitated by the interaction of hLysRS with a tRNA-like element (TLE) first identified in the HIV-1 5'-untranslated region (5'-UTR) of the subtype B NL4-3 virus. However, a significant subset of HIV-1 strains represented by the MAL isolate possess a different secondary structure in this region of the genome. Thus, to establish the conservation of this mechanism for primer targeting and release, we investigated the subtype A-like 5'-UTR of the MAL isolate. hLysRS bound to a 229-nt MAL RNA containing the PBS domain with high affinity (Kd = 47 nM), and to a 98-nt truncated construct with ∼10-fold reduced affinity. These results resemble previous studies using analogous NL4-3-derived RNAs. However, in contrast to studies with NL4-3, no binding was observed to smaller stem-loop elements within the MAL PBS domain. The tertiary structure of the 98-nt construct was analyzed using small-angle X-ray scattering, revealing remarkable global structural similarity to the corresponding NL4-3 PBS/TLE region. These results suggest that the tRNA-like structure within the 5'-UTR is conserved across distinct HIV-1 subtypes and that hLysRS recognition of the MAL isolate is likely not conferred by specific sequence elements but by 3D structure.
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Affiliation(s)
- Roopa Comandur
- Department of Chemistry and Biochemistry, Center for Retrovirus Research and Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA
| | - Erik D Olson
- Department of Chemistry and Biochemistry, Center for Retrovirus Research and Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA
| | - Karin Musier-Forsyth
- Department of Chemistry and Biochemistry, Center for Retrovirus Research and Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA
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13
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Comas-Garcia M, Datta SA, Baker L, Varma R, Gudla PR, Rein A. Dissection of specific binding of HIV-1 Gag to the 'packaging signal' in viral RNA. eLife 2017; 6. [PMID: 28726630 PMCID: PMC5531834 DOI: 10.7554/elife.27055] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Accepted: 07/13/2017] [Indexed: 01/26/2023] Open
Abstract
Selective packaging of HIV-1 genomic RNA (gRNA) requires the presence of a cis-acting RNA element called the 'packaging signal' (Ψ). However, the mechanism by which Ψ promotes selective packaging of the gRNA is not well understood. We used fluorescence correlation spectroscopy and quenching data to monitor the binding of recombinant HIV-1 Gag protein to Cy5-tagged 190-base RNAs. At physiological ionic strength, Gag binds with very similar, nanomolar affinities to both Ψ-containing and control RNAs. We challenged these interactions by adding excess competing tRNA; introducing mutations in Gag; or raising the ionic strength. These modifications all revealed high specificity for Ψ. This specificity is evidently obscured in physiological salt by non-specific, predominantly electrostatic interactions. This nonspecific activity was attenuated by mutations in the MA, CA, and NC domains, including CA mutations disrupting Gag-Gag interaction. We propose that gRNA is selectively packaged because binding to Ψ nucleates virion assembly with particular efficiency.
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Affiliation(s)
- Mauricio Comas-Garcia
- HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, Frederick, United States
| | - Siddhartha Ak Datta
- HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, Frederick, United States
| | - Laura Baker
- HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, Frederick, United States
| | | | - Prabhakar R Gudla
- Optical Microscopy and Analysis Laboratory, Cancer Research Technology Program, Leidos Biomedical Research, Inc., Frederick, United States
| | - Alan Rein
- HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, Frederick, United States
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14
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Roy A, Mir MA. Development of High-Throughput Screening Assay for Antihantaviral Therapeutics. SLAS DISCOVERY 2017; 22:767-774. [PMID: 28340538 DOI: 10.1177/2472555217699942] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Humans acquire hantavirus infection by the inhalation of aerosolized excreta of infected rodent hosts. There is no treatment for hantavirus diseases at present. Therapeutic intervention during early stages of viral infection can improve the outcome of this zoonotic viral illness. The interaction between an evolutionary conserved sequence at the 5' terminus of hantaviral genomic RNA and hantavirus nucleocapsid protein plays a critical role in the hantavirus replication cycle. This unique interaction is a novel target for therapeutic intervention of hantavirus disease. We developed a very sensitive, tractable, and cost-effective fluorescence-based assay to monitor the interaction between the nucleocapsid protein and the target RNA sequence. The assay was optimized for high-throughput screening of chemical libraries to identify molecules that interrupt this RNA-protein interaction. The assay was validated using a library of 6880 chemical compounds. This validation screen demonstrated the reproducibility and validity of required statistical criteria for high-throughput screening. The assay is ready to use for high-throughput screening of large chemical libraries to identify antihantaviral therapeutic molecules and can be amenable to similar targets in other viruses.
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Affiliation(s)
- Anuradha Roy
- 1 High-Throughput Screening Lab, University of Kansas, Lawrence, KS, USA
| | - Mohammad A Mir
- 2 College of Veterinary Medicine, Western University of Health Sciences, Pomona, CA, USA
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15
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Todd GC, Duchon A, Inlora J, Olson ED, Musier-Forsyth K, Ono A. Inhibition of HIV-1 Gag-membrane interactions by specific RNAs. RNA (NEW YORK, N.Y.) 2017; 23:395-405. [PMID: 27932583 PMCID: PMC5311501 DOI: 10.1261/rna.058453.116] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 12/07/2016] [Indexed: 05/03/2023]
Abstract
HIV-1 particle assembly, which occurs at the plasma membrane (PM) of cells, is driven by the viral polyprotein Gag. Gag recognizes phosphatidylinositol-(4,5)-bisphosphate [PI(4,5)P2], a PM-specific phospholipid, via the highly basic region (HBR) in its N-terminal matrix (MA) domain. The HBR is also known to bind to RNA. We have previously shown, using an in vitro liposome binding assay, that RNA inhibits Gag binding to membranes that lack PI(4,5)P2 If this RNA block is removed by RNase treatment, Gag can bind nonspecifically to other negatively charged membranes. In an effort to identify the RNA species that confer this inhibition of Gag membrane binding, we have tested the impact of purified RNAs on Gag interactions with negatively charged liposomes lacking PI(4,5)P2 We found that some tRNA species and RNAs containing stem-loop 1 of the psi region in the 5' untranslated region of the HIV-1 genome impose inhibition of Gag binding to membranes lacking PI(4,5)P2 In contrast, a specific subset of tRNAs, as well as an RNA sequence previously selected in vitro for MA binding, failed to suppress Gag-membrane interactions. Furthermore, switching the identity of charged residues in the HBR did not diminish the susceptibility of Gag-liposome binding for each of the RNAs tested, while deletion of most of the NC domain abrogates the inhibition of membrane binding mediated by the RNAs that are inhibitory to WT Gag-liposome binding. These results support a model in which NC facilitates binding of RNA to MA and thereby promotes RNA-based inhibition of Gag-membrane binding.
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MESH Headings
- Aptamers, Nucleotide/chemical synthesis
- Aptamers, Nucleotide/pharmacology
- Base Pairing
- Base Sequence
- Binding Sites
- Cell Membrane/chemistry
- Cell Membrane/drug effects
- Cell Membrane/metabolism
- Cloning, Molecular
- Escherichia coli/genetics
- Escherichia coli/metabolism
- Gene Expression
- HIV-1/chemistry
- Humans
- Liposomes/antagonists & inhibitors
- Liposomes/chemistry
- Nucleic Acid Conformation
- Phosphatidylinositol 4,5-Diphosphate/chemistry
- Phosphatidylinositol 4,5-Diphosphate/deficiency
- Protein Binding/drug effects
- RNA, Transfer/chemistry
- RNA, Transfer/pharmacology
- Recombinant Proteins/chemistry
- Recombinant Proteins/genetics
- Recombinant Proteins/metabolism
- Saccharomyces cerevisiae/chemistry
- Static Electricity
- gag Gene Products, Human Immunodeficiency Virus/antagonists & inhibitors
- gag Gene Products, Human Immunodeficiency Virus/chemistry
- gag Gene Products, Human Immunodeficiency Virus/genetics
- gag Gene Products, Human Immunodeficiency Virus/metabolism
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Affiliation(s)
- Gabrielle C Todd
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan 48109, USA
| | - Alice Duchon
- Department of Chemistry and Biochemistry, Center for RNA Biology, and Center for Retrovirus Research, The Ohio State University, Columbus, Ohio 43210, USA
| | - Jingga Inlora
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan 48109, USA
| | - Erik D Olson
- Department of Chemistry and Biochemistry, Center for RNA Biology, and Center for Retrovirus Research, The Ohio State University, Columbus, Ohio 43210, USA
| | - Karin Musier-Forsyth
- Department of Chemistry and Biochemistry, Center for RNA Biology, and Center for Retrovirus Research, The Ohio State University, Columbus, Ohio 43210, USA
| | - Akira Ono
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan 48109, USA
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16
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Post K, Olson ED, Naufer MN, Gorelick RJ, Rouzina I, Williams MC, Musier-Forsyth K, Levin JG. Mechanistic differences between HIV-1 and SIV nucleocapsid proteins and cross-species HIV-1 genomic RNA recognition. Retrovirology 2016; 13:89. [PMID: 28034301 PMCID: PMC5198506 DOI: 10.1186/s12977-016-0322-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Accepted: 11/29/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The nucleocapsid (NC) domain of HIV-1 Gag is responsible for specific recognition and packaging of genomic RNA (gRNA) into new viral particles. This occurs through specific interactions between the Gag NC domain and the Psi packaging signal in gRNA. In addition to this critical function, NC proteins are also nucleic acid (NA) chaperone proteins that facilitate NA rearrangements during reverse transcription. Although the interaction with Psi and chaperone activity of HIV-1 NC have been well characterized in vitro, little is known about simian immunodeficiency virus (SIV) NC. Non-human primates are frequently used as a platform to study retroviral infection in vivo; thus, it is important to understand underlying mechanistic differences between HIV-1 and SIV NC. RESULTS Here, we characterize SIV NC chaperone activity for the first time. Only modest differences are observed in the ability of SIV NC to facilitate reactions that mimic the minus-strand annealing and transfer steps of reverse transcription relative to HIV-1 NC, with the latter displaying slightly higher strand transfer and annealing rates. Quantitative single molecule DNA stretching studies and dynamic light scattering experiments reveal that these differences are due to significantly increased DNA compaction energy and higher aggregation capability of HIV-1 NC relative to the SIV protein. Using salt-titration binding assays, we find that both proteins are strikingly similar in their ability to specifically interact with HIV-1 Psi RNA. In contrast, they do not demonstrate specific binding to an RNA derived from the putative SIV packaging signal. CONCLUSIONS Based on these studies, we conclude that (1) HIV-1 NC is a slightly more efficient NA chaperone protein than SIV NC, (2) mechanistic differences between the NA interactions of highly similar retroviral NC proteins are revealed by quantitative single molecule DNA stretching, and (3) SIV NC demonstrates cross-species recognition of the HIV-1 Psi RNA packaging signal.
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Affiliation(s)
- Klara Post
- Section on Viral Gene Regulation, Program in Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892-2780 USA
| | - Erik D. Olson
- Department of Chemistry and Biochemistry, Center for Retrovirus Research, and Center for RNA Biology, The Ohio State University, Columbus, OH 43210 USA
| | - M. Nabuan Naufer
- Department of Physics, Northeastern University, Boston, MA 02115 USA
| | - Robert J. Gorelick
- AIDS and Cancer Virus Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702-1201 USA
| | - Ioulia Rouzina
- Department of Chemistry and Biochemistry, Center for Retrovirus Research, and Center for RNA Biology, The Ohio State University, Columbus, OH 43210 USA
| | - Mark C. Williams
- Department of Physics, Northeastern University, Boston, MA 02115 USA
| | - Karin Musier-Forsyth
- Department of Chemistry and Biochemistry, Center for Retrovirus Research, and Center for RNA Biology, The Ohio State University, Columbus, OH 43210 USA
| | - Judith G. Levin
- Section on Viral Gene Regulation, Program in Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892-2780 USA
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17
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Liu S, Comandur R, Jones CP, Tsang P, Musier-Forsyth K. Anticodon-like binding of the HIV-1 tRNA-like element to human lysyl-tRNA synthetase. RNA (NEW YORK, N.Y.) 2016; 22:1828-1835. [PMID: 27852925 PMCID: PMC5113203 DOI: 10.1261/rna.058081.116] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Accepted: 09/10/2016] [Indexed: 06/06/2023]
Abstract
A critical step in the HIV-1 lifecycle involves reverse transcription of the viral genomic RNA (gRNA). Human tRNALys3 serves as a primer for transcription initiation and is selectively enriched in virus particles. Human lysyl-tRNA synthetase (hLysRS) is also packaged into virions. Recently, a tRNA-like element (TLE) within the HIV-1 gRNA was shown to mimic the global tRNA fold and bind competitively to hLysRS, suggesting a mechanism of tRNA targeting to the primer binding site (PBS) and release from the synthetase. Here, we use NMR to investigate hLysRS anticodon-binding domain (ACB) binding to six RNA oligonucleotides, including a hairpin derived from the HIV-1 gRNA TLE. We show that ACB interacts with submicromolar affinity to U-rich RNA oligonucleotides-the tRNALys3 anticodon stem-loop (ACSL), the WT TLE, and a nonanucleotide, U9. In contrast, the ACB bound only weakly to two TLE loop mutants and a C9 nonanucleotide. NMR chemical shift perturbations induced by each RNA indicate that the ACSL and the WT TLE both interact with the ACB in a strikingly similar manner. Taken together, these findings support the conclusion that tRNA mimicry by the HIV-1 genome leads to a highly specific protein-RNA interaction that facilitates efficient primer release from hLysRS prior to reverse transcription.
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Affiliation(s)
- Sheng Liu
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221-0172, USA
| | - Roopa Comandur
- Department of Chemistry and Biochemistry, Center for Retrovirus Research and Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA
| | - Christopher P Jones
- Department of Chemistry and Biochemistry, Center for Retrovirus Research and Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA
| | - Pearl Tsang
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221-0172, USA
| | - Karin Musier-Forsyth
- Department of Chemistry and Biochemistry, Center for Retrovirus Research and Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA
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18
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Rye-McCurdy T, Olson ED, Liu S, Binkley C, Reyes JP, Thompson BR, Flanagan JM, Parent LJ, Musier-Forsyth K. Functional Equivalence of Retroviral MA Domains in Facilitating Psi RNA Binding Specificity by Gag. Viruses 2016; 8:v8090256. [PMID: 27657107 PMCID: PMC5035970 DOI: 10.3390/v8090256] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Revised: 09/09/2016] [Accepted: 09/12/2016] [Indexed: 12/18/2022] Open
Abstract
Retroviruses specifically package full-length, dimeric genomic RNA (gRNA) even in the presence of a vast excess of cellular RNA. The “psi” (Ψ) element within the 5′-untranslated region (5′UTR) of gRNA is critical for packaging through interaction with the nucleocapsid (NC) domain of Gag. However, in vitro Gag binding affinity for Ψ versus non-Ψ RNAs is not significantly different. Previous salt-titration binding assays revealed that human immunodeficiency virus type 1 (HIV-1) Gag bound to Ψ RNA with high specificity and relatively few charge interactions, whereas binding to non-Ψ RNA was less specific and involved more electrostatic interactions. The NC domain was critical for specific Ψ binding, but surprisingly, a Gag mutant lacking the matrix (MA) domain was less effective at discriminating Ψ from non-Ψ RNA. We now find that Rous sarcoma virus (RSV) Gag also effectively discriminates RSV Ψ from non-Ψ RNA in a MA-dependent manner. Interestingly, Gag chimeras, wherein the HIV-1 and RSV MA domains were swapped, maintained high binding specificity to cognate Ψ RNAs. Using Ψ RNA mutant constructs, determinants responsible for promoting high Gag binding specificity were identified in both systems. Taken together, these studies reveal the functional equivalence of HIV-1 and RSV MA domains in facilitating Ψ RNA selectivity by Gag, as well as Ψ elements that promote this selectivity.
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Affiliation(s)
- Tiffiny Rye-McCurdy
- Department of Chemistry and Biochemistry, The Ohio State University, Center for Retroviral Research, and Center for RNA Biology, Columbus, OH 43210, USA.
| | - Erik D Olson
- Department of Chemistry and Biochemistry, The Ohio State University, Center for Retroviral Research, and Center for RNA Biology, Columbus, OH 43210, USA.
| | - Shuohui Liu
- Department of Chemistry and Biochemistry, The Ohio State University, Center for Retroviral Research, and Center for RNA Biology, Columbus, OH 43210, USA.
| | - Christiana Binkley
- Department of Chemistry and Biochemistry, The Ohio State University, Center for Retroviral Research, and Center for RNA Biology, Columbus, OH 43210, USA.
| | - Joshua-Paolo Reyes
- Department of Chemistry and Biochemistry, The Ohio State University, Center for Retroviral Research, and Center for RNA Biology, Columbus, OH 43210, USA.
| | - Brian R Thompson
- Department of Chemistry and Biochemistry, The Ohio State University, Center for Retroviral Research, and Center for RNA Biology, Columbus, OH 43210, USA.
| | - John M Flanagan
- Department of Biochemistry and Molecular Biology, Penn State College of Medicine, Hershey, PA 17033, USA.
| | - Leslie J Parent
- Departments of Medicine and Microbiology and Immunology, Division of Infectious Diseases and Epidemiology, Penn State College of Medicine, Hershey, PA 17033, USA.
| | - Karin Musier-Forsyth
- Department of Chemistry and Biochemistry, The Ohio State University, Center for Retroviral Research, and Center for RNA Biology, Columbus, OH 43210, USA.
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