Characterization of recombinant expression of Bombyx mori bidensovirus ns1 using a modified vector.

ns1 gene of Bombyx mori bidensovirus (BmBDV) consisted of 951 nucleotides encoding a deduced 316-amino aicd protein. In this study, the gene was cloned and fused in frame with a N-terminal 6×His tag under control of the polyhedrin promoter, which was transposed into the mini-attTn7 locus of a modified baculovirus vector. Transfection of Sf-9 cells with the resulting recombinant DNA was performed to prepare recombinant virus and the resultant supernatant of transfection with fluorescent signal was harvested. Western blot analysis revealed that NS1 protein was successfully expressed in Sf9 cells infected with the recombinant virus and was confirmed by LC-MS/MS analysis. Moreover, the expressed NS1 is a phosphorylated protein and the phosphorylation site is Thr-184. These results showed that the activity of BmBDV NS1 may be regulated by phosphorylation.