An insect picorna-like virus, Plautia stall intestine virus, has genes of capsid proteins in the 3' part of the genome

The complete genome of an insect picorna-like virus, Plautia stall intestine virus (PSIV), was cloned and sequenced. The genome had 8797 nucleotides including two consecutive long open reading frames. The deduced amino acid sequence of the first open reading frame (nucleotides 571 to 6003) contained conserved sequence motifs for picornavirus RNA helicase, cysteine protease, and RNA-dependent RNA polymerase. The order of the three motifs in the genome was the same as those of mammalian picornaviruses. The coding regions of four capsid proteins (33, 30, 26, and 4.5 kDa) were mapped by determining their N-terminal sequences. Unlike mammalian picornaviruses, the genes for these proteins were in the 3' region of the PSIV genome. In vitro translation assay suggested that the capsid protein precursor of PSIV would be translated by internal initiation. The deduced amino acid sequence of the capsid proteins showed homology to those of the proteins encoded in the 3' part of the genomes of widely distributed insect picorna-like viruses, cricket paralysis virus, and Drosophila C virus. Some insect picorna-like viruses would have the same unique coding strategy as PSIV.