Discovery of a unique novel clade of mosquito-associated bunyaviruses

• Type of Material: Article
• Authors: Marco Marklewitz, University of Bonn; Florian Zirkel, University of Bonn; Innocent B. Rwego, University of Bonn; Hanna Heidemann, University of Bonn; Pascal Trippner, University of Bonn; Andreas Kurth, Robert Koch Institute; René Kallies, University of Bonn; Thomas Briese, Columbia University; W. Ian Lipkin, Columbia University; Christian Drosten, University of Bonn; Thomas Gillespie, Emory University; Sandra Junglen, University of Bonn
• Language: English
• Date: 2013-12-01
• Publisher: American Society for Microbiology
• Publication Version: Final Published Version
• Copyright Statement: © 2013, American Society for Microbiology.
• Final Published Version (URL): http://dx.doi.org/10.1128/JVI.01862-13
• Title of Journal or Parent Work: Journal of Virology
• ISSN: 0022-538X
• Volume: 87
• Issue: 23
• Start Page: 12850
• End Page: 12865
• Grant/Funding Information: The project was supported by the National Institutes of Health (AI057158 Northeast Biodefense Center—Lipkin); by the United States Department of Defense and the United States Agency for International Development (USAID) Emerging Pandemic Threats (EPT) Program, PREDICT project, under the terms of cooperative agreement GHN-A-OO-09-00010-00; by European Union DG Research through the program ANTIGONE (grant agreement no. 278976); and by the Deutsche Forschungsgemeinschaft (grant agreement no. DR 772/3-1).; Funding for fieldwork in Uganda was provided by the Emory University Global Health Institute.
• Keywords: Viral Proteins; Amino Acid Sequence; Bunyaviridae Infections; Molecular Sequence Data; Animals; Insect Vectors; Cell Line; Mice; Culicidae; Genome, Viral; Phylogeny; Humans; Bunyaviridae; Sequence Alignment; Base Sequence
• Research Categories: Biology, Virology; Biology, Ecology; Health Sciences, Public Health

Abstract

Bunyaviruses are the largest known family of RNA viruses, infecting vertebrates, insects, and plants. Here we isolated three novel bunyaviruses from mosquitoes sampled in Côte d'Ivoire, Ghana, and Uganda. The viruses define a highly diversified monophyletic sister clade to all members of the genus Orthobunyavirus and are virtually equidistant to orthobunyaviruses and tospoviruses. Maximal amino acid identities between homologous putative proteins of the novel group and orthobunyaviruses ranged between 12 and 25%. The type isolates, tentatively named Herbert virus (HEBV), Taï virus (TAIV), and Kibale virus (KIBV), comprised genomes with L, M, and S segments of about 7.4 kb, 2.7 kb, and 1.1 kb, respectively. HEBV, TAIV, and KIBV encode the shortest bunyavirusMsegments known and did not seem to encode NSs and NSm proteins but contained an elongated L segment with an ~500-nucleotide (nt) insertion that shows no identity to other bunyaviruses. The viruses replicated to high titers in insect cells but did not replicate in vertebrate cells. The enveloped virions were 90 to 110 nm in diameter and budded at cellular membranes with morphological features typical of the Golgi complex. Viral RNA recovered from infected cells showed 5'-terminal nontemplated sequences of 9 to 22 nt, suggestive of cap snatching during mRNA synthesis, as described for other bunyaviruses. Northern blotting identified RNA species of full and reduced lengths, suggested upon analogy with other bunyaviruses to constitute antigenomic-sense cRNA and transcript mRNAs, respectively. Functional studies will be necessary to determine if this group of viruses constitutes a novel genus in the bunyavirus family.