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Kleiner VA, Fearns R. How does the polymerase of non-segmented negative strand RNA viruses commit to transcription or genome replication? J Virol 2024; 98:e0033224. [PMID: 39078194 PMCID: PMC11334523 DOI: 10.1128/jvi.00332-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/31/2024] Open
Abstract
The Mononegavirales, or non-segmented negative-sense RNA viruses (nsNSVs), includes significant human pathogens, such as respiratory syncytial virus, parainfluenza virus, measles virus, Ebola virus, and rabies virus. Although these viruses differ widely in their pathogenic properties, they are united by each having a genome consisting of a single strand of negative-sense RNA. Consistent with their shared genome structure, the nsNSVs have evolved similar ways to transcribe their genome into mRNAs and replicate it to produce new genomes. Importantly, both mRNA transcription and genome replication are performed by a single virus-encoded polymerase. A fundamental and intriguing question is: how does the nsNSV polymerase commit to being either an mRNA transcriptase or a replicase? The polymerase must become committed to one process or the other either before it interacts with the genome template or in its initial interactions with the promoter sequence at the 3´ end of the genomic RNA. This review examines the biochemical, molecular biology, and structural biology data regarding the first steps of transcription and RNA replication that have been gathered over several decades for different families of nsNSVs. These findings are discussed in relation to possible models that could explain how an nsNSV polymerase initiates and commits to either transcription or genome replication.
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Affiliation(s)
- Victoria A. Kleiner
- Department of Virology, Immunology & Microbiology, Boston University Chobanian & Avedisian School of Medicine, Boston, Massachusetts, USA
| | - Rachel Fearns
- Department of Virology, Immunology & Microbiology, Boston University Chobanian & Avedisian School of Medicine, Boston, Massachusetts, USA
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2
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Liu X, Stahelin RV, Pienaar E. Impact of Ebola virus nucleoprotein on VP40 virus-like particle production: a computational approach. Commun Biol 2024; 7:634. [PMID: 38796621 PMCID: PMC11128010 DOI: 10.1038/s42003-024-06300-8] [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: 08/15/2023] [Accepted: 05/07/2024] [Indexed: 05/28/2024] Open
Abstract
Ebola virus (EBOV) matrix protein VP40 can assemble and bud as virus-like particles (VLPs) when expressed alone in mammalian cells. Nucleoprotein (NP) could be recruited to VLPs as inclusion body (IB) when co-expressed, and increase VLP production. However, the mechanism behind it remains unclear. Here, we use a computational approach to study NP-VP40 interactions. Our simulations indicate that NP may enhance VLP production through stabilizing VP40 filaments and accelerating the VLP budding step. Further, both the relative timing and amount of NP expression compared to VP40 are important for the effective production of IB-containing VLPs. We predict that relative NP/VP40 expression ratio and time are important for efficient production of IB-containing VLPs. We conclude that disrupting the expression timing and amount of NP and VP40 could provide new avenues to treat EBOV infection. This work provides quantitative insights into EBOV proteins interactions and how virion generation and drug efficacy could be influenced.
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Affiliation(s)
- Xiao Liu
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA
| | - Robert V Stahelin
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN, USA
| | - Elsje Pienaar
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA.
- Regenstrief Center for Healthcare Engineering, Purdue University, West Lafayette, IN, USA.
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3
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Ferrero DS, Tomás Gilabert O, Verdaguer N. Structural insights on the nucleoprotein C-terminal domain of Měnglà virus. Microbiol Spectr 2023; 11:e0237323. [PMID: 37888996 PMCID: PMC10714759 DOI: 10.1128/spectrum.02373-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Accepted: 09/19/2023] [Indexed: 10/28/2023] Open
Abstract
IMPORTANCE Filoviruses are the causative agents of severe and often fatal hemorrhagic disease in humans. Měnglà virus (MLAV) is a recently reported filovirus, isolated from fruit bats that is capable to replicate in human cells, representing a potential risk for human health. An in-depth structural and functional knowledge of MLAV proteins is an essential step for antiviral research on this virus that can also be extended to other emerging filoviruses. In this study, we determined the first crystal structures of the C-terminal domain (CTD) of the MLAV nucleoprotein (NP), showing important similarities to the equivalent domain in MARV. The structural data also show that the NP CTD has the ability to form large helical oligomers that may participate in the control of cytoplasmic inclusion body formation during viral replication.
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Affiliation(s)
| | | | - Nuria Verdaguer
- Molecular Biology Institute of Barcelona (IBMB-CSIC), Barcelona, Spain
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4
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Zinzula L, Mereu AM, Orsini M, Seeleitner C, Bracher A, Nagy I, Baumeister W. Ebola and Marburg virus VP35 coiled-coil validated as antiviral target by tripartite split-GFP complementation. iScience 2022; 25:105354. [PMID: 36325051 PMCID: PMC9619376 DOI: 10.1016/j.isci.2022.105354] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 09/29/2022] [Accepted: 10/11/2022] [Indexed: 11/30/2022] Open
Abstract
Ebola virus (EBOV) and Marburg virus (MARV) are highly pathogenic viruses in humans, against which approved antivirals are lacking. During EBOV and MARV infection, coiled-coil mediated oligomerization is essential for the virion protein 35 (VP35) polymerase co-factor function and type I interferon antagonism, making VP35 coiled-coil an elective drug target. We established a tripartite split-green fluorescent protein (GFP) fluorescence complementation (FC) system based on recombinant GFP-tagged EBOV and MARV VP35, which probes VP35 coiled-coil assembly by monitoring fluorescence on E. coli colonies, or in vitro in 96/384-multiwell. Oligomerization-defective VP35 mutants showed that correct coiled-coil knobs-into-holes pairing within VP35 oligomer is pre-requisite for GFP tags and GFP detector to reconstitute fluorescing full-length GFP. The method was validated by screening a small compound library, which identified Myricetin and 4,5,6,7-Tetrabromobenzotriazole as inhibitors of EBOV and MARV VP35 oligomerization-dependent FC with low-micromolar IC50 values. These findings substantiate the VP35 coiled-coil value as antiviral target. Ebola and Marburg virus VP35 oligomerize via trimeric and tetrameric coiled-coil VP35 coiled-coil assembly triggers fluorescence of a tripartite split-GFP system Mutations perturbing VP35 coiled-coil hamper split-GFP complementation Myricetin and TBBT inhibit split-GFP complementation mediated by VP35 coiled-coil
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Affiliation(s)
- Luca Zinzula
- The Max-Planck Institute of Biochemistry, Department of Molecular Structural Biology, Am Klopferspitz 18, 82152 Martinsried, Germany
- Corresponding author
| | - Angela Maria Mereu
- The Max-Planck Institute of Biochemistry, Department of Molecular Structural Biology, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Massimiliano Orsini
- Istituto Zooprofilattico Sperimentale delle Venezie, Department of Risk Analysis and Public Health Surveillance, Viale dell’Università 10, 35020 Legnaro, Italy
| | - Christine Seeleitner
- The Max-Planck Institute of Biochemistry, Department of Molecular Structural Biology, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Andreas Bracher
- The Max-Planck Institute of Biochemistry, Department of Cellular Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - István Nagy
- The Max-Planck Institute of Biochemistry, Department of Molecular Structural Biology, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Wolfgang Baumeister
- The Max-Planck Institute of Biochemistry, Department of Molecular Structural Biology, Am Klopferspitz 18, 82152 Martinsried, Germany
- Corresponding author
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5
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Dong X, Wang X, Xie M, Wu W, Chen Z. Structural Basis of Human Parainfluenza Virus 3 Unassembled Nucleoprotein in Complex with Its Viral Chaperone. J Virol 2022; 96:e0164821. [PMID: 34730394 PMCID: PMC8791282 DOI: 10.1128/jvi.01648-21] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Accepted: 10/30/2021] [Indexed: 11/20/2022] Open
Abstract
Human parainfluenza virus 3 (HPIV3) belongs to the Paramyxoviridae, causing annual worldwide epidemics of respiratory diseases, especially in newborns and infants. The core components consist of just three viral proteins: nucleoprotein (N), phosphoprotein (P), and RNA polymerase (L), playing essential roles in replication and transcription of HPIV3 as well as other paramyxoviruses. Viral genome encapsidated by N is as a template and recognized by RNA-dependent RNA polymerase complex composed of L and P. The offspring RNA also needs to assemble with N to form nucleocapsids. The N is one of the most abundant viral proteins in infected cells and chaperoned in the RNA-free form (N0) by P before encapsidation. In this study, we presented the structure of unassembled HPIV3 N0 in complex with the N-terminal portion of the P, revealing the molecular details of the N0 and the conserved N0-P interaction. Combined with biological experiments, we showed that the P binds to the C-terminal domain of N0 mainly by hydrophobic interaction and maintains the unassembled conformation of N by interfering with the formation of N-RNA oligomers, which might be a target for drug development. Based on the complex structure, we developed a method to obtain the monomeric N0. Furthermore, we designed a P-derived fusion peptide with 10-fold higher affinity, which hijacked the N and interfered with the binding of the N to RNA significantly. Finally, we proposed a model of conformational transition of N from the unassembled state to the assembled state, which helped to further understand viral replication. IMPORTANCE Human parainfluenza virus 3 (HPIV3) causes annual epidemics of respiratory diseases, especially in newborns and infants. For the replication of HPIV3 and other paramyxoviruses, only three viral proteins are required: phosphoprotein (P), RNA polymerase (L), and nucleoprotein (N). Here, we report the crystal structure of the complex of N and its chaperone P. We describe in detail how P acts as a chaperone to maintain the unassembled conformation of N. Our analysis indicated that the interaction between P and N is conserved and mediated by hydrophobicity, which can be used as a target for drug development. We obtained a high-affinity P-derived peptide inhibitor, specifically targeted N, and greatly interfered with the binding of the N to RNA, thereby inhibiting viral encapsidation and replication. In summary, our results provide new insights into the paramyxovirus genome replication and nucleocapsid assembly and lay the basis for drug development.
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Affiliation(s)
- Xiaofei Dong
- State Key Laboratory of Agrobiotechnology and Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Xue Wang
- State Key Laboratory of Agrobiotechnology and Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Mengjia Xie
- State Key Laboratory of Agrobiotechnology and Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Wei Wu
- State Key Laboratory of Agrobiotechnology and Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Zhongzhou Chen
- State Key Laboratory of Agrobiotechnology and Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Biological Sciences, China Agricultural University, Beijing, China
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The Nucleocapsid of Paramyxoviruses: Structure and Function of an Encapsidated Template. Viruses 2021; 13:v13122465. [PMID: 34960734 PMCID: PMC8708338 DOI: 10.3390/v13122465] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 12/07/2021] [Accepted: 12/07/2021] [Indexed: 01/28/2023] Open
Abstract
Viruses of the Paramyxoviridae family share a common and complex molecular machinery for transcribing and replicating their genomes. Their non-segmented, negative-strand RNA genome is encased in a tight homopolymer of viral nucleoproteins (N). This ribonucleoprotein complex, termed a nucleocapsid, is the template of the viral polymerase complex made of the large protein (L) and its co-factor, the phosphoprotein (P). This review summarizes the current knowledge on several aspects of paramyxovirus transcription and replication, including structural and functional data on (1) the architecture of the nucleocapsid (structure of the nucleoprotein, interprotomer contacts, interaction with RNA, and organization of the disordered C-terminal tail of N), (2) the encapsidation of the genomic RNAs (structure of the nucleoprotein in complex with its chaperon P and kinetics of RNA encapsidation in vitro), and (3) the use of the nucleocapsid as a template for the polymerase complex (release of the encased RNA and interaction network allowing the progress of the polymerase complex). Finally, this review presents models of paramyxovirus transcription and replication.
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Zinzula L, Beck F, Klumpe S, Bohn S, Pfeifer G, Bollschweiler D, Nagy I, Plitzko JM, Baumeister W. Cryo-EM structure of the cetacean morbillivirus nucleoprotein-RNA complex. J Struct Biol 2021; 213:107750. [PMID: 34089875 DOI: 10.1016/j.jsb.2021.107750] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 05/17/2021] [Accepted: 05/31/2021] [Indexed: 11/30/2022]
Abstract
Cetacean morbillivirus (CeMV) is an emerging and highly infectious paramyxovirus that causes outbreaks in cetaceans and occasionally in pinnipeds, representing a major threat to biodiversity and conservation of endangered marine mammal populations in both hemispheres. As for all non-segmented, negative-sense, single-stranded RNA (ssRNA) viruses, the morbilliviral genome is enwrapped by thousands of nucleoprotein (N) protomers. Each bound to six ribonucleotides, N protomers assemble to form a helical ribonucleoprotein (RNP) complex that serves as scaffold for nucleocapsid formation and as template for viral replication and transcription. While the molecular details on RNP complexes elucidated in human measles virus (MeV) served as paradigm model for these processes in all members of the Morbillivirus genus, no structural information has been obtained from other morbilliviruses, nor has any CeMV structure been solved so far. We report the structure of the CeMV RNP complex, reconstituted in vitro upon binding of recombinant CeMV N to poly-adenine ssRNA hexamers and solved to 4.0 Å resolution by cryo-electron microscopy. In spite of the amino acid sequence similarity and consequently similar folding of the N protomer, the CeMV RNP complex exhibits different helical parameters as compared to previously reported MeV orthologs. The CeMV structure reveals exclusive interactions leading to more extensive protomer-RNA and protomer-protomer interfaces. We identified twelve residues, among those varying between CeMV strains, as putatively important for the stabilization of the RNP complex, which highlights the need to study the potential of CeMV N mutations that modulate nucleocapsid assembly to also affect viral phenotype and host adaptation.
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Affiliation(s)
- Luca Zinzula
- Max-Planck Institute of Biochemistry, Department of Molecular Structural Biology, Am Klopferspitz 18, 82152 Martinsried, Germany.
| | - Florian Beck
- Max-Planck Institute of Biochemistry, Department of Molecular Structural Biology, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Sven Klumpe
- Max-Planck Institute of Biochemistry, Department of Molecular Structural Biology, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Stefan Bohn
- Max-Planck Institute of Biochemistry, Department of Molecular Structural Biology, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Günter Pfeifer
- Max-Planck Institute of Biochemistry, Department of Molecular Structural Biology, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Daniel Bollschweiler
- Max-Planck Institute of Biochemistry, Cryo-EM Facility, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - István Nagy
- Max-Planck Institute of Biochemistry, Department of Molecular Structural Biology, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Jürgen M Plitzko
- Max-Planck Institute of Biochemistry, Department of Molecular Structural Biology, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Wolfgang Baumeister
- Max-Planck Institute of Biochemistry, Department of Molecular Structural Biology, Am Klopferspitz 18, 82152 Martinsried, Germany.
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Luo M, Terrell JR, Mcmanus SA. Nucleocapsid Structure of Negative Strand RNA Virus. Viruses 2020; 12:E835. [PMID: 32751700 PMCID: PMC7472042 DOI: 10.3390/v12080835] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 07/23/2020] [Accepted: 07/27/2020] [Indexed: 12/14/2022] Open
Abstract
Negative strand RNA viruses (NSVs) include many important human pathogens, such as influenza virus, Ebola virus, and rabies virus. One of the unique characteristics that NSVs share is the assembly of the nucleocapsid and its role in viral RNA synthesis. In NSVs, the single strand RNA genome is encapsidated in the linear nucleocapsid throughout the viral replication cycle. Subunits of the nucleocapsid protein are parallelly aligned along the RNA genome that is sandwiched between two domains composed of conserved helix motifs. The viral RNA-dependent-RNA polymerase (vRdRp) must recognize the protein-RNA complex of the nucleocapsid and unveil the protected genomic RNA in order to initiate viral RNA synthesis. In addition, vRdRp must continuously translocate along the protein-RNA complex during elongation in viral RNA synthesis. This unique mechanism of viral RNA synthesis suggests that the nucleocapsid may play a regulatory role during NSV replication.
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Affiliation(s)
- Ming Luo
- Department of Chemistry, Georgia State University, Atlanta, GA 30302, USA; (J.R.T.); (S.A.M.)
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Lin AE, Diehl WE, Cai Y, Finch CL, Akusobi C, Kirchdoerfer RN, Bollinger L, Schaffner SF, Brown EA, Saphire EO, Andersen KG, Kuhn JH, Luban J, Sabeti PC. Reporter Assays for Ebola Virus Nucleoprotein Oligomerization, Virion-Like Particle Budding, and Minigenome Activity Reveal the Importance of Nucleoprotein Amino Acid Position 111. Viruses 2020; 12:E105. [PMID: 31952352 PMCID: PMC7019320 DOI: 10.3390/v12010105] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 01/09/2020] [Accepted: 01/13/2020] [Indexed: 01/17/2023] Open
Abstract
For highly pathogenic viruses, reporter assays that can be rapidly performed are critically needed to identify potentially functional mutations for further study under maximal containment (e.g., biosafety level 4 [BSL-4]). The Ebola virus nucleoprotein (NP) plays multiple essential roles during the viral life cycle, yet few tools exist to study the protein under BSL-2 or equivalent containment. Therefore, we adapted reporter assays to measure NP oligomerization and virion-like particle (VLP) production in live cells and further measured transcription and replication using established minigenome assays. As a proof-of-concept, we examined the NP-R111C substitution, which emerged during the 2013‒2016 Western African Ebola virus disease epidemic and rose to high frequency. NP-R111C slightly increased NP oligomerization and VLP budding but slightly decreased transcription and replication. By contrast, a synthetic charge-reversal mutant, NP-R111E, greatly increased oligomerization but abrogated transcription and replication. These results are intriguing in light of recent structures of NP oligomers, which reveal that the neighboring residue, K110, forms a salt bridge with E349 on adjacent NP molecules. By developing and utilizing multiple reporter assays, we find that the NP-111 position mediates a complex interplay between NP's roles in protein structure, virion budding, and transcription and replication.
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Affiliation(s)
- Aaron E. Lin
- Harvard Program in Virology, Harvard Medical School, Boston, MA 02115, USA
- Department of Organismic and Evolutionary Biology, FAS Center for Systems Biology, Harvard University, Cambridge, MA 02138, USA; (S.F.S.); (E.A.B.)
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - William E. Diehl
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA; (W.E.D.); (J.L.)
| | - Yingyun Cai
- Integrated Research Facility at Fort Detrick, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Frederick, MD 21702, USA; (Y.C.); (C.L.F.); (L.B.); (J.H.K.)
| | - Courtney L. Finch
- Integrated Research Facility at Fort Detrick, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Frederick, MD 21702, USA; (Y.C.); (C.L.F.); (L.B.); (J.H.K.)
| | - Chidiebere Akusobi
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA 02120, USA;
| | | | - Laura Bollinger
- Integrated Research Facility at Fort Detrick, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Frederick, MD 21702, USA; (Y.C.); (C.L.F.); (L.B.); (J.H.K.)
| | - Stephen F. Schaffner
- Department of Organismic and Evolutionary Biology, FAS Center for Systems Biology, Harvard University, Cambridge, MA 02138, USA; (S.F.S.); (E.A.B.)
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Elizabeth A. Brown
- Department of Organismic and Evolutionary Biology, FAS Center for Systems Biology, Harvard University, Cambridge, MA 02138, USA; (S.F.S.); (E.A.B.)
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | | | - Kristian G. Andersen
- Department of Immunology and Microbial Sciences, The Scripps Research Institute, La Jolla, CA 92037, USA;
- Scripps Translational Science Institute, La Jolla, CA 92037, USA
| | - Jens H. Kuhn
- Integrated Research Facility at Fort Detrick, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Frederick, MD 21702, USA; (Y.C.); (C.L.F.); (L.B.); (J.H.K.)
| | - Jeremy Luban
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA; (W.E.D.); (J.L.)
| | - Pardis C. Sabeti
- Harvard Program in Virology, Harvard Medical School, Boston, MA 02115, USA
- Department of Organismic and Evolutionary Biology, FAS Center for Systems Biology, Harvard University, Cambridge, MA 02138, USA; (S.F.S.); (E.A.B.)
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA
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