Nucleotide sequences of genome segments 6 and 7 of Bombyx mori cypovirus 1, encoding the viral structural proteins V4 and V5, respectively

Nucleotide sequence analyses of cDNAs derived from the double-stranded RNA genome segments 6 and 7 (S6 and S7) of Bombyx mori cypovirus 1 (BmCPV-1) have revealed that they consist of 1796 and 1501 nucleotides encoding putative proteins of 561 and 448 amino acids with molecular masses of 63604 and 49875 (p64 and p50), respectively. The amino acid sequence of p64, which has a high leucine residue content (10%), contains a leucine zipper motif. Antiserum raised against p64 specifically bound to a viral structural protein of ca. 68 kDa (V4), while antiserum against p50, which specifically bound to a protein of ca. 56 kDa in BmN4 cells infected with BmCPV-1, reacted with a cluster of four viral structural proteins ranging from ca. 34 to 40 kDa (V5). These observations indicate that p50 might be cleaved to V5 during the formation of virus particles.