Nucleotide sequence analysis of Triatoma virus shows that it is a member of a novel group of insect RNA viruses

Triatoma virus (TrV) is the only virus described to date that infects triat omines, and has previously been considered to be a member of the family Pic ornaviridae on the basis of physico-chemical properties. The genome of TrV was sequenced completely (9010 nt), Analysis of the sequence revealed the p resence of two large open reading frames (ORFs). The predicted amino acid s equence of ORF1 (nt 549-5936) showed significant similarity to the non-stru ctural proteins of several animal and plant RNA viruses. This ORF product c ontains sequence motifs characteristic of RNA-dependent RNA polymerases (Rd Rp), cysteine proteases and RNA helicases, ORF1 is preceded by 548 nucleoti des of non-coding RNA and the two ORFs are separated by 172 nucleotides of non-coding RNA. Direct N terminus sequence analysis of two capsid proteins showed that ORF2 (nt 6109-8715) encodes the structural proteins of TrV. The predicted amino acid sequence of ORF2 is very similar to the corresponding regions of Drosophila C virus, Plautia stall intestine virus, Rhopalosiphu m padi virus and Himetobi P virus and to a partial sequence from the 3' end of the cricket paralysis virus genome. All of these viruses have a novel g enome organization and it has been proposed that they are not members of th e Picornaviridae, as previously thought, but belong to a new virus family. On the basis of similarities of genome organization, we propose that TrV al so belongs to this new virus family.