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Coggins SA, Holler JM, Kimata JT, Kim DH, Schinazi RF, Kim B. Efficient pre-catalytic conformational change of reverse transcriptases from SAMHD1 non-counteracting primate lentiviruses during dNTP incorporation. Virology 2019; 537:36-44. [PMID: 31442614 DOI: 10.1016/j.virol.2019.08.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 08/10/2019] [Accepted: 08/12/2019] [Indexed: 10/26/2022]
Abstract
Unlike HIV-1, HIV-2 and some SIV strains replicate at high dNTP concentrations even in macrophages due to their accessory proteins, Vpx or Vpr, that target SAMHD1 dNTPase for proteasomal degradation. We previously reported that HIV-1 reverse transcriptase (RT) efficiently synthesizes DNA even at low dNTP concentrations because HIV-1 RT displays faster pre-steady state kpol values than SAMHD1 counteracting lentiviral RTs. Here, since the kpol step consists of two sequential sub-steps post dNTP binding, conformational change and chemistry, we investigated which of the two sub-steps RTs from SAMHD1 non-counteracting viruses accelerate in order to complete reverse transcription in the limited dNTP pools found in macrophages. Our study demonstrates that RTs of SAMHD1 non-counteracting lentiviruses have a faster conformational change rate during dNTP incorporation, supporting that these lentiviruses may have evolved to harbor RTs that can efficiently execute the conformational change step in order to circumvent SAMHD1 restriction and dNTP depletion in macrophages.
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Affiliation(s)
- Si'Ana A Coggins
- Department of Pediatrics, School of Medicine, Emory University, Atlanta, GA, 30322, USA
| | - Jessica M Holler
- Department of Pediatrics, School of Medicine, Emory University, Atlanta, GA, 30322, USA
| | - Jason T Kimata
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, 77030, Texas, USA
| | - Dong-Hyun Kim
- College of Pharmacy, Kyung Hee University, Seoul, 04427, South Korea
| | - Raymond F Schinazi
- Department of Pediatrics, School of Medicine, Emory University, Atlanta, GA, 30322, USA
| | - Baek Kim
- Department of Pediatrics, School of Medicine, Emory University, Atlanta, GA, 30322, USA; College of Pharmacy, Kyung Hee University, Seoul, 04427, South Korea; Children's Healthcare of Atlanta, Atlanta, 30322, USA.
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2
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Daly MB, Roth ME, Bonnac L, Maldonado JO, Xie J, Clouser CL, Patterson SE, Kim B, Mansky LM. Dual anti-HIV mechanism of clofarabine. Retrovirology 2016; 13:20. [PMID: 27009333 PMCID: PMC4806454 DOI: 10.1186/s12977-016-0254-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Accepted: 03/17/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND HIV-1 replication kinetics inherently depends on the availability of cellular dNTPs for viral DNA synthesis. In activated CD4(+) T cells and other rapidly dividing cells, the concentrations of dNTPs are high and HIV-1 reverse transcription occurs in an efficient manner. In contrast, nondividing cells such as macrophages have lower dNTP pools, which restricts efficient reverse transcription. Clofarabine is an FDA approved ribonucleotide reductase inhibitor, which has shown potent antiretroviral activity in transformed cell lines. Here, we explore the potency, toxicity and mechanism of action of clofarabine in the human primary HIV-1 target cells: activated CD4(+) T cells and macrophages. RESULTS Clofarabine is a potent HIV-1 inhibitor in both activated CD4(+) T cells and macrophages. Due to its minimal toxicity in macrophages, clofarabine displays a selectivity index over 300 in this nondividing cell type. The anti-HIV-1 activity of clofarabine correlated with a significant decrease in both cellular dNTP levels and viral DNA synthesis. Additionally, we observed that clofarabine triphosphate was directly incorporated into DNA by HIV-1 reverse transcriptase and blocked processive DNA synthesis, particularly at the low dNTP levels found in macrophages. CONCLUSIONS Taken together, these data provide strong mechanistic evidence that clofarabine is a dual action inhibitor of HIV-1 replication that both limits dNTP substrates for viral DNA synthesis and directly inhibits the DNA polymerase activity of HIV-1 reverse transcriptase.
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Affiliation(s)
- Michele B Daly
- Center for Drug Discovery, Department of Pediatrics, Emory Center for AIDS Research, Emory University, Children's Healthcare of Atlanta, 1760 Haygood Dr., Atlanta, GA, 30322, USA
| | - Megan E Roth
- Institute for Molecular Virology, University of Minnesota, 18-242 Moos Tower, 515 Delaware St SE, Minneapolis, MN, 55455, USA.,Department of Diagnostic and Biological Sciences, School of Dentistry, University of Minnesota, Minneapolis, MN, 55455, USA.,Department of Microbiology and Immunology, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Laurent Bonnac
- Center for Drug Design, Academic Health Center, University of Minnesota, Minneapolis, MN, 55455, USA
| | - José O Maldonado
- Institute for Molecular Virology, University of Minnesota, 18-242 Moos Tower, 515 Delaware St SE, Minneapolis, MN, 55455, USA.,Department of Diagnostic and Biological Sciences, School of Dentistry, University of Minnesota, Minneapolis, MN, 55455, USA.,Department of Microbiology and Immunology, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Jiashu Xie
- Center for Drug Design, Academic Health Center, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Christine L Clouser
- Institute for Molecular Virology, University of Minnesota, 18-242 Moos Tower, 515 Delaware St SE, Minneapolis, MN, 55455, USA
| | - Steven E Patterson
- Center for Drug Design, Academic Health Center, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Baek Kim
- Center for Drug Discovery, Department of Pediatrics, Emory Center for AIDS Research, Emory University, Children's Healthcare of Atlanta, 1760 Haygood Dr., Atlanta, GA, 30322, USA.
| | - Louis M Mansky
- Institute for Molecular Virology, University of Minnesota, 18-242 Moos Tower, 515 Delaware St SE, Minneapolis, MN, 55455, USA. .,Department of Diagnostic and Biological Sciences, School of Dentistry, University of Minnesota, Minneapolis, MN, 55455, USA. .,Department of Microbiology and Immunology, University of Minnesota, Minneapolis, MN, 55455, USA. .,Center for Drug Design, Academic Health Center, University of Minnesota, Minneapolis, MN, 55455, USA.
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Hollenbaugh JA, Schader SM, Schinazi RF, Kim B. Differential regulatory activities of viral protein X for anti-viral efficacy of nucleos(t)ide reverse transcriptase inhibitors in monocyte-derived macrophages and activated CD4(+) T cells. Virology 2015; 485:313-21. [PMID: 26319213 PMCID: PMC4619155 DOI: 10.1016/j.virol.2015.08.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Revised: 07/27/2015] [Accepted: 08/08/2015] [Indexed: 01/05/2023]
Abstract
Vpx encoded by HIV-2 and SIVsm enhances retroviral reverse transcription in macrophages in vitro by mediating the degradation of the host SAMHD1 protein that hydrolyzes dNTPs and by elevating cellular dNTP levels. Here we employed RT-SHIV constructs (SIV encoding HIV-1 RT) to investigate the contribution of Vpx to the potency of NRTIs, which compete against dNTPs, in monocyte-derived macrophages (MDMs) and activated CD4(+) T cells. Relative to HIV-1, both SIV and RT-SHIV exhibited reduced sensitivities to AZT, 3TC and TDF in MDMs but not in activated CD4(+) T cells. However, when SIV and RT-SHIV constructs not coding for Vpx were utilized, we observed greater sensitivities to all NRTIs tested using activated CD4(+) T cells relative to the Vpx-coding counterparts. This latter phenomenon was observed for AZT only when using MDMs. Our data suggest that Vpx in RT-SHIVs may underestimate the antiviral efficacy of NRTIs in a cell type dependent manner.
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Affiliation(s)
- Joseph A Hollenbaugh
- Center for Drug Discovery, Department of Pediatrics, Emory University, Atlanta, GA, USA
| | - Susan M Schader
- Center for Drug Discovery, Department of Pediatrics, Emory University, Atlanta, GA, USA
| | - Raymond F Schinazi
- Center for Drug Discovery, Department of Pediatrics, Emory University, Atlanta, GA, USA; Veterans Affairs Medical Center, Atlanta, GA, USA
| | - Baek Kim
- Center for Drug Discovery, Department of Pediatrics, Emory University, Atlanta, GA, USA; College of Pharmacy, Kyung Hee University, Seoul, South Korea.
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Lenzi GM, Domaoal RA, Kim DH, Schinazi RF, Kim B. Mechanistic and Kinetic Differences between Reverse Transcriptases of Vpx Coding and Non-coding Lentiviruses. J Biol Chem 2015; 290:30078-86. [PMID: 26483545 PMCID: PMC4705996 DOI: 10.1074/jbc.m115.691576] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Indexed: 11/06/2022] Open
Abstract
Among lentiviruses, HIV Type 2 (HIV-2) and many simian immunodeficiency virus (SIV) strains replicate rapidly in non-dividing macrophages, whereas HIV Type 1 (HIV-1) replication in this cell type is kinetically delayed. The efficient replication capability of HIV-2/SIV in non-dividing cells is induced by a unique, virally encoded accessory protein, Vpx, which proteasomally degrades the host antiviral restriction factor, SAM domain- and HD domain-containing protein 1 (SAMHD1). SAMHD1 is a dNTPase and kinetically suppresses the reverse transcription step of HIV-1 in macrophages by hydrolyzing and depleting cellular dNTPs. In contrast, Vpx, which is encoded by HIV-2/SIV, kinetically accelerates reverse transcription by counteracting SAMHD1 and then elevating cellular dNTP concentration in non-dividing cells. Here, we conducted the pre-steady-state kinetic analysis of reverse transcriptases (RTs) from two Vpx non-coding and two Vpx coding lentiviruses. At all three sites of the template tested, the two RTs of the Vpx non-coding viruses (HIV-1) displayed higher kpol values than the RTs of the Vpx coding HIV-2/SIV, whereas there was no significant difference in the Kd values of these two groups of RTs. When we employed viral RNA templates that induce RT pausing by their secondary structures, the HIV-1 RTs showed more efficient DNA synthesis through pause sites than the HIV-2/SIV RTs, particularly at low dNTP concentrations found in macrophages. This kinetic study suggests that RTs of the Vpx non-coding HIV-1 may have evolved to execute a faster kpol step, which includes the conformational changes and incorporation chemistry, to counteract the limited dNTP concentration found in non-dividing cells and still promote efficient viral reverse transcription.
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Affiliation(s)
- Gina M Lenzi
- From the Center for Drug Discovery, Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia 30322
| | - Robert A Domaoal
- From the Center for Drug Discovery, Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia 30322
| | - Dong-Hyun Kim
- the College of Pharmacy, Kyung-Hee University, Seoul 02447, South Korea
| | - Raymond F Schinazi
- From the Center for Drug Discovery, Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia 30322, the Veterans Affairs Medical Center, Decatur, Georgia 30033
| | - Baek Kim
- From the Center for Drug Discovery, Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia 30322, the College of Pharmacy, Kyung-Hee University, Seoul 02447, South Korea,
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Rehwinkel J, Maelfait J, Bridgeman A, Rigby R, Hayward B, Liberatore RA, Bieniasz PD, Towers GJ, Moita LF, Crow YJ, Bonthron DT, Reis e Sousa C. SAMHD1-dependent retroviral control and escape in mice. EMBO J 2013; 32:2454-62. [PMID: 23872947 PMCID: PMC3770946 DOI: 10.1038/emboj.2013.163] [Citation(s) in RCA: 128] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Accepted: 07/01/2013] [Indexed: 12/12/2022] Open
Abstract
SAMHD1 is a host restriction factor for human immunodeficiency virus 1 (HIV-1) in cultured human cells. SAMHD1 mutations cause autoimmune Aicardi-Goutières syndrome and are found in cancers including chronic lymphocytic leukaemia. SAMHD1 is a triphosphohydrolase that depletes the cellular pool of deoxynucleoside triphosphates, thereby preventing reverse transcription of retroviral genomes. However, in vivo evidence for SAMHD1's antiviral activity has been lacking. We generated Samhd1 null mice that do not develop autoimmune disease despite displaying a type I interferon signature in spleen, macrophages and fibroblasts. Samhd1(-/-) cells have elevated deoxynucleoside triphosphate (dNTP) levels but, surprisingly, SAMHD1 deficiency did not lead to increased infection with VSV-G-pseudotyped HIV-1 vectors. The lack of restriction is likely attributable to the fact that dNTP concentrations in SAMHD1-sufficient mouse cells are higher than the KM of HIV-1 reverse transcriptase (RT). Consistent with this notion, an HIV-1 vector mutant bearing an RT with lower affinity for dNTPs was sensitive to SAMHD1-dependent restriction in cultured cells and in mice. This shows that SAMHD1 can restrict lentiviruses in vivo and that nucleotide starvation is an evolutionarily conserved antiviral mechanism.
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Affiliation(s)
- Jan Rehwinkel
- Immunobiology Laboratory, Cancer Research UK, London Research Institute, London, UK
- Medical Research Council Human Immunology Unit, Radcliffe Department of Medicine, Medical Research Council Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - Jonathan Maelfait
- Medical Research Council Human Immunology Unit, Radcliffe Department of Medicine, Medical Research Council Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - Anne Bridgeman
- Medical Research Council Human Immunology Unit, Radcliffe Department of Medicine, Medical Research Council Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - Rachel Rigby
- Medical Research Council Human Immunology Unit, Radcliffe Department of Medicine, Medical Research Council Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - Bruce Hayward
- Leeds Institute of Molecular Medicine, University of Leeds, St James’s University Hospital, Leeds, UK
| | - Rachel A Liberatore
- Laboratory of Retrovirology, Aaron Diamond AIDS Research Center, Howard Hughes Medical Institute, The Rockefeller University, New York, NY, USA
| | - Paul D Bieniasz
- Laboratory of Retrovirology, Aaron Diamond AIDS Research Center, Howard Hughes Medical Institute, The Rockefeller University, New York, NY, USA
| | - Greg J Towers
- Division of Infection and Immunity, University College London, London, UK
| | - Luis F Moita
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Yanick J Crow
- Manchester Centre for Genomic Medicine, Manchester Academic Health Sciences Centre, University of Manchester, Manchester, UK
| | - David T Bonthron
- Leeds Institute of Molecular Medicine, University of Leeds, St James’s University Hospital, Leeds, UK
| | - Caetano Reis e Sousa
- Immunobiology Laboratory, Cancer Research UK, London Research Institute, London, UK
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Daddacha W, Noble E, Nguyen LA, Kennedy EM, Kim B. Effect of ribonucleotides embedded in a DNA template on HIV-1 reverse transcription kinetics and fidelity. J Biol Chem 2013; 288:12522-32. [PMID: 23479739 DOI: 10.1074/jbc.m113.458398] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
HIV-1 reverse transcriptase (RT) frequently incorporates ribonucleoside triphosphates (rNTPs) during proviral DNA synthesis, particularly under the limited dNTP conditions found in macrophages. We investigated the mechanistic impacts of an rNMP embedded in DNA templates on HIV-1 RT-mediated DNA synthesis. We observed that the template-embedded rNMP induced pausing of RT and delayed DNA synthesis kinetics at low macrophage dNTP concentrations but not at high T cell dNTP concentrations. Although the binding affinity of RT to the rNMP-containing template-primer was not altered, the dNTP incorporation kinetics of RT were significantly reduced at one nucleotide upstream and downstream of the rNMP site, leading to pause sites. Finally, HIV-1 RT becomes more error-prone at rNMP sites with an elevated mismatch extension capability but not enhanced misinsertion capability. Together these data suggest that rNMPs embedded in DNA templates may influence reverse transcription kinetics and impact viral mutagenesis in macrophages.
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Affiliation(s)
- Waaqo Daddacha
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, New York 14642, USA
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7
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Kennedy EM, Daddacha W, Slater R, Gavegnano C, Fromentin E, Schinazi RF, Kim B. Abundant non-canonical dUTP found in primary human macrophages drives its frequent incorporation by HIV-1 reverse transcriptase. J Biol Chem 2011; 286:25047-55. [PMID: 21454906 PMCID: PMC3137078 DOI: 10.1074/jbc.m111.234047] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2011] [Revised: 03/29/2011] [Indexed: 01/21/2023] Open
Abstract
Terminally differentiated/non-dividing macrophages contain extremely low cellular dNTP concentrations (20-40 nm), compared with activated CD4(+) T cells (2-5 μm). However, our LC-MS/MS study revealed that the non-canonical dUTP concentration (2.9 μm) is ∼60 times higher than TTP in macrophages, whereas the concentrations of dUTP and TTP in dividing human primary lymphocytes are very similar. Specifically, we evaluated the contribution of HIV-1 reverse transcriptase to proviral DNA uracilation under the physiological conditions found in HIV-1 target cells. Indeed, biochemical simulation of HIV-1 reverse transcription demonstrates that HIV-1 RT efficiently incorporates dUTP in the macrophage nucleotide pools but not in the T cell nucleotide pools. Measurement of both pre-steady state and steady state kinetic parameters of dUTP incorporation reveals minimal selectivity of HIV-1 RT for TTP over dUTP, implying that the cellular dUTP/TTP ratio determines the frequency of HIV-1 RT-mediated dUTP incorporation. The RT of another lentivirus, simian immunodeficiency virus, also displays efficient dUTP incorporation in the dNTP/dUTP pools found in macrophages but not in T cells. Finally, 2',3'-dideoxyuridine was inhibitory to HIV-1 proviral DNA synthesis in macrophages but not in T cells. The data presented demonstrates that the non-canonical dUTP was abundant relative to TTP, and efficiently incorporated during HIV-1 reverse transcription, particularly in non-dividing macrophages.
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Affiliation(s)
- Edward M. Kennedy
- From the Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, New York 14642 and
| | - Waaqo Daddacha
- From the Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, New York 14642 and
| | - Rebecca Slater
- From the Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, New York 14642 and
| | - Christina Gavegnano
- the Center for AIDS Research, Laboratory of Biochemical Pharmacology, Department of Pediatrics, Emory University School of Medicine and Veterans Affairs Medical Center, Decatur, Georgia 30033
| | - Emilie Fromentin
- the Center for AIDS Research, Laboratory of Biochemical Pharmacology, Department of Pediatrics, Emory University School of Medicine and Veterans Affairs Medical Center, Decatur, Georgia 30033
| | - Raymond F. Schinazi
- the Center for AIDS Research, Laboratory of Biochemical Pharmacology, Department of Pediatrics, Emory University School of Medicine and Veterans Affairs Medical Center, Decatur, Georgia 30033
| | - Baek Kim
- From the Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, New York 14642 and
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Kennedy EM, Gavegnano C, Nguyen L, Slater R, Lucas A, Fromentin E, Schinazi RF, Kim B. Ribonucleoside triphosphates as substrate of human immunodeficiency virus type 1 reverse transcriptase in human macrophages. J Biol Chem 2010; 285:39380-91. [PMID: 20924117 PMCID: PMC2998149 DOI: 10.1074/jbc.m110.178582] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2010] [Revised: 10/04/2010] [Indexed: 01/04/2023] Open
Abstract
We biochemically simulated HIV-1 DNA polymerization in physiological nucleotide pools found in two HIV-1 target cell types: terminally differentiated/non-dividing macrophages and activated/dividing CD4(+) T cells. Quantitative tandem mass spectrometry shows that macrophages harbor 22-320-fold lower dNTP concentrations and a greater disparity between ribonucleoside triphosphate (rNTP) and dNTP concentrations than dividing target cells. A biochemical simulation of HIV-1 reverse transcription revealed that rNTPs are efficiently incorporated into DNA in the macrophage but not in the T cell environment. This implies that HIV-1 incorporates rNTPs during viral replication in macrophages and also predicts that rNTP chain terminators lacking a 3'-OH should inhibit HIV-1 reverse transcription in macrophages. Indeed, 3'-deoxyadenosine inhibits HIV-1 proviral DNA synthesis in human macrophages more efficiently than in CD4(+) T cells. This study reveals that the biochemical landscape of HIV-1 replication in macrophages is unique and that ribonucleoside chain terminators may be a new class of anti-HIV-1 agents specifically targeting viral macrophage infection.
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Affiliation(s)
- Edward M. Kennedy
- From the Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, New York 14642, and
| | - Christina Gavegnano
- the Center for AIDS Research, Laboratory of Biochemical Pharmacology, Department of Pediatrics, Emory University School of Medicine and Veterans Affairs Medical Center, Decatur, Georgia 30033
| | - Laura Nguyen
- From the Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, New York 14642, and
| | - Rebecca Slater
- From the Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, New York 14642, and
| | - Amanda Lucas
- From the Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, New York 14642, and
| | - Emilie Fromentin
- the Center for AIDS Research, Laboratory of Biochemical Pharmacology, Department of Pediatrics, Emory University School of Medicine and Veterans Affairs Medical Center, Decatur, Georgia 30033
| | - Raymond F. Schinazi
- the Center for AIDS Research, Laboratory of Biochemical Pharmacology, Department of Pediatrics, Emory University School of Medicine and Veterans Affairs Medical Center, Decatur, Georgia 30033
| | - Baek Kim
- From the Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, New York 14642, and
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Aggarwal S, Bradel-Tretheway B, Takimoto T, Dewhurst S, Kim B. Biochemical characterization of enzyme fidelity of influenza A virus RNA polymerase complex. PLoS One 2010; 5:e10372. [PMID: 20454455 PMCID: PMC2861597 DOI: 10.1371/journal.pone.0010372] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2010] [Accepted: 04/07/2010] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND It is widely accepted that the highly error prone replication process of influenza A virus (IAV), together with viral genome assortment, facilitates the efficient evolutionary capacity of IAV. Therefore, it has been logically assumed that the enzyme responsible for viral RNA replication process, influenza virus type A RNA polymerase (IAV Pol), is a highly error-prone polymerase which provides the genomic mutations necessary for viral evolution and host adaptation. Importantly, however, the actual enzyme fidelity of IAV RNA polymerase has never been characterized. PRINCIPAL FINDINGS Here we established new biochemical assay conditions that enabled us to assess both polymerase activity with physiological NTP pools and enzyme fidelity of IAV Pol. We report that IAV Pol displays highly active RNA-dependent RNA polymerase activity at unbiased physiological NTP substrate concentrations. With this robust enzyme activity, for the first time, we were able to compare the enzyme fidelity of IAV Pol complex with that of bacterial phage T7 RNA polymerase and the reverse transcriptases (RT) of human immunodeficiency virus (HIV-1) and murine leukemia virus (MuLV), which are known to be low and high fidelity enzymes, respectively. We observed that IAV Pol displayed significantly higher fidelity than HIV-1 RT and T7 RNA polymerase and equivalent or higher fidelity than MuLV RT. In addition, the IAV Pol complex showed increased fidelity at lower temperatures. Moreover, upon replacement of Mg(++) with Mn(++), IAV Pol displayed increased polymerase activity, but with significantly reduced processivity, and misincorporation was slightly elevated in the presence of Mn(++). Finally, when the IAV nucleoprotein (NP) was included in the reactions, the IAV Pol complex exhibited enhanced polymerase activity with increased fidelity. SIGNIFICANCE Our study indicates that IAV Pol is a high fidelity enzyme. We envision that the high fidelity nature of IAV Pol may be important to counter-balance the multiple rounds of IAV genome amplification per infection cycle, which provides IAV Pol with ample opportunities to generate and amplify genomic founder mutations, and thus achieve optimal viral mutagenesis for its evolution.
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Affiliation(s)
- Shilpa Aggarwal
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, New York, United States of America
| | - Birgit Bradel-Tretheway
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, New York, United States of America
| | - Toru Takimoto
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, New York, United States of America
| | - Stephen Dewhurst
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, New York, United States of America
| | - Baek Kim
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, New York, United States of America
- * E-mail:
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