Construction of a Bombyx mori cell line that stably express the susceptible gene +nsd-2 of Bombyx mori bidensovirus

Abstract

Bombyx mori bidensovirus (BmBDV) is the only type species established in the new genus
Bidensovirus within the new family Bidnaviridae. The BmBDV infected silkworm midgut shows symptoms such as the nucleus of midgut columnar cells expanded. It is confirmed the
BmBDV-sensitive gene +nsd-2, which encoding an amino acid transporter protein might be the receptor of BmBDV. The deletion of this gene causes the silkworm resistance to BmBDV infection. There is no permissive cell line for BmBDV infection has been established yet. The cell lines (BmN, etc.) are used broadly for silkworm viruses study are mainly resistant to BmBDV infection. Therefore, the establishment of BmBDV permissive cell line is particularly important for studying BmBDV in vitro. In this study, we successfully constructed a cell line BmN (+nsd-2), which expressed +nsd-2 gene stably. The NSD-2 expression and localization could be detected in BmN (+nsd-2 ) cells via RT-PCR, western blot and immunofluorescence. The interaction between NSD-2 and the major structural protein VP of BmBDV was determined by Co-IP. However, we failed to detect the replication of BmBDV. This cell lines constructed has the potential for identifying the protein binding to the NSD-2 and provide a basis for study of BmBDV co-receptors and invasion mechanism.