Identification of a Flavivirus Sequence in a Marine Arthropod.

Michael J Conway

doi:10.1371/journal.pone.0146037

Abstract

Phylogenetic analysis has yet to uncover the early origins of flaviviruses. In this study, I mined a database of expressed sequence tags in order to discover novel flavivirus sequences. Flavivirus sequences were identified in a pool of mRNA extracted from the sea spider Endeis spinosa (Pycnogonida, Pantopoda). Reconstruction of the translated sequences and BLAST analysis matched the sequence to the flavivirus NS5 gene. Additional sequences corresponding to envelope and the NS5 MTase domain were also identified. Phylogenetic analysis of homologous NS5 sequences revealed that Endeis spinosa NS5 (ESNS5) is likely related to classical insect-specific flaviviruses. It is unclear if ESNS5 represents genetic material from an active viral infection or an integrated viral genome. These data raise the possibility that classical insect-specific flaviviruses and perhaps medically relevant flaviviruses, evolved from progenitors that infected marine arthropods.

Highlights

Viruses in the genus Flavivirus share a common genomic organization and certain antigenic relationships; they can be divided into distinct phylogenetic groups [1]
Translated nucleotide BLAST database searches were performed by searching for flavivirus sequences in the expressed sequence tag database. 100 cDNA clones were identified and accession numbers are available in S1 Table
Protein BLAST analysis suggested that this protein, which we call Endeis spinosa NS5 (ESNS5), is most related to “no known vector” and tick-borne flaviviruses (Table 3)

Summary

Introduction

Viruses in the genus Flavivirus share a common genomic organization and certain antigenic relationships; they can be divided into distinct phylogenetic groups [1]. Phylogenetic analysis of flaviviruses has been reported using individual genes and whole genomes and trees have been built using both amino acid and nucleotide sequences [1, 11,12,13,14,15,16]. These studies have yet to uncover the early origins of flaviviruses [11, 12]. Our current database of genetic material may only represent the tips of the evolutionary tree [12, 17]

Methods

Results

Conclusion