Nucleocapsid protemn gene of Chinese isolate of Bombyx mori nucleopolyhedrovirus.

The nucleocapsid protein gene (vp39) of a Chinese isolate of Bombyx mori nucleopolyhedrovirus (BmNPV-Ch), namely an open reading frame (ORF) of 1050 bp that codes for a polypeptide of 39 K (VP39) consisting of 350 amino acids was sequenced. The homology of the nucleotide (nt) and amino acid sequences of vp39 and VP39, respectively, of BmNPV-Ch and a Japanese isolate of BmNPV (BmNPV-Ja) were found to be 97.5% and 97.1%, respectively. The BmNPV-Ch vp39 is nine nucleotides longer than that of BmNPV-Ja vp39 due to insertion of CGA at nt 625 and GTCGGC at nt 985 910. There are differences in 17 nucleotides causing a few substitutions of amino acids which slightly modify the secondary structure of BmNPV-Ch. It indicates that the main part of the secondary structure of VP39 is a folded structure containing high proportion of beta-sheet and beta-turn units. A dot blot hybridization analysis revealed the existence of a homologous transcript of BmNPV-Ch vp39 in Sf9 cells infected with Autographa californica multiple nucleocapsid nucleopolyhedrovirus (AcMNPV).