Identification, Characterization, and In Vitro Culture of Highly Divergent Arenaviruses from Boa Constrictors and Annulated Tree Boas: Candidate Etiological Agents for Snake Inclusion Body Disease

Stenglein, Mark D.; Sanders, Chris; Kistler, Amy L.; Ruby, J. Graham; Franco, Jessica Y.; Reavill, Drury R.; Dunker, Freeland; DeRisi, Joseph L.

Phylogenetic relationships. To further investigate the relationship between these viruses and previously described arenaviruses, we conducted comparative and phylogenetic analyses of the four major open reading frames (L, NP, Z, and GPC) present on CASV and GGV. In arenaviruses, L is the large RNA-dependent polymerase involved in viral genome replication and transcription (20, 21, 23) . NP, the viral nucleoprotein, forms a circular ribonucleoprotein complex with the genome-length viral RNAs (21, 24) . The predicted snake proteins share 23 to 26% and 17 to 19% pairwise amino acid identity with the lymphocytic chorio-meningitis virus (LCMV), Lassa virus (LASV), and Tacaribe virus (TCRV) L and NP proteins, respectively (Fig. 3C ). These viruses were selected for comparison as representative members of the two major clades of previously described arenaviruses: the Old World (OW) and New World (NW) arenaviruses, also known as the Lassa/LCMV and Tacaribe serocomplexes (20, 21, 25, 26) . The CASV and GGV L and NP protein sequences are 55% and 50% identical in amino acids, respectively, or roughly as similar as the L and NP proteins of LCMV and LASV, which are 47% and 62% identical, respectively. In phylogenies, the snake virus proteins form a monophyletic clade separate from those formed by the Old World and New World arenaviruses (Fig. 3D ).