Identification and characterization of vp7 gene in Bombyx mori cytoplasmic polyhedrosis virus

Abstract

The genome of Bombyx mori cytoplasmic polyhedrosis virus (BmCPV) contains 10 double stranded RNA segments (S1-S10). The segment 7 (S7) encodes 50kDa protein which is considered as a structural protein. The expression pattern and function of p50 in the virus life cycle are still unclear. In this study, the viral structural protein 7 (VP7) polyclonal antibody was prepared with immunized mouse to explore the presence of small VP7 gene-encoded proteins in Bombyx mori cytoplasmic polyhedrosis virus. The expression pattern of vp7 gene was investigated by its overexpression in BmN cells. In addition to VP7, supplementary band was identified with western blotting technique. The virion, BmCPV infected cells and midguts were also examined using western blotting technique. 4, 2 and 5 bands were detected in the corresponding samples, respectively. The replication of BmCPV genome in the cultured cells and midgut of silkworm was decreased by reducing the expression level of vp7 gene using RNA interference. In immunoprecipitation experiments, using a polyclonal antiserum directed against the VP7, one additional shorter band in BmCPV infected midguts was detected, and then the band was analyzed with mass spectrum (MS), the MS results showed thatone candidate interacted protein (VP7 voltage-dependent anion-selective channel-like isoform, VDAC) was identified from silkworm. We concluded that the novel viral product was generated with a leaky scanning mechanism and the VDAC may be an interacted protein with VP7.

Characterization of the lipidomic profile of BmN cells in response to Bombyx mori cytoplasmic polyhedrosis virus infection

“…BmN cells with (CASE) and without (CON) BmCPV infection were collected by centrifugation and the precipitates were washed with PBS buffer at 4 °C. To evaluate BmCPV infection in BmN cells, a proportion of the cell precipitates were used for total protein extraction followed by western blotting to detect BmCPV structural protein VP7using anti-mouse VP7 primary antibody ( He et al, 2017 ) and horseradish peroxidase (HRP)-conjugated anti-rabbit IgG secondary antibody (Abcam). The expression level of vp1 gene was detected from CASE samples using real-time PCR with the primer pair qvp1-F(5′-GGTCTCGACGTGAATACCGA-3′) and (qvp1-R: 5′-TCGTCTGCTTCACTAGCACG-3′).…”

“…The host response of silkworms to BmCPV infection has been comprehensively explored, including the expression pattern analysis of genes ( Kolliopoulou et al, 2015 ; Guo et al, 2015 ), proteins ( Gao et al, 2017 ) and non-coding RNAs ( Hu et al, 2018 ). In addition, the function of BmCPV genes ( He et al, 2017 ), viral encoded non-coding RNAs ( Guo et al, 2019 ; Zografidis et al, 2015 ) and viral peptide ( Hu et al, 2019a ) have also been identified. Our previous studies have found alterations in a large number of genes related to important signaling pathways, including those associated with innate immunity, development and metabolism following BmCPV infection ( Guo et al, 2015 ; Hu et al, 2018 ).…”

RNAi for plant improvement and protection

“…Cypoviruses (cytoplasmic polyhedrosis viruses (CPVs); genus: Cypovirus; family: Reoviridae) are widespread pathogens of insects. The type species is Cypovirus 1, which specifically infects silkworms (Bombyx mori) and negatively affects the sericulture industry (Cao et al, 2012;He et al, 2017;Zhao et al, 2019). In contrast to all other reoviruses, CPV virions consist of one layer of capsid that corresponds to the core particle of other reoviruses (discussed above for BTV).…”

“…After feeding, CPV polyhedra are lysed because of the high pH in the lepidopteran midgut, which results in the infection of the midgut epithelium by the released virions. Interestingly, electron microscope images show that CPV virions can directly penetrate the plasma membrane of the microvilli that are localized at the apical sides of the enterocytes during midgut infection of silkworm larvae (Cao et al, 2012;He et al, 2017;Zhao et al, 2019). Functional studies also show the involvement of clathrin-mediated endocytosis for uptake of CPV virions in silkworm-derived BmN cells and the midgut epithelium (Tan et al, 2003).…”

Glycoproteome in silkworm Bombyx mori and alteration by BmCPV infection

“…BmCPV is a double stranded RNA virus belonging to the Cypovirus genus, Reoviridae family. Its genome contains 10 discrete copacked RNA segments [8], but only a few of them has been cloned and characterized so far [9,10]. The RNA genome is wrapped by 5 structural proteins, T namely VP1-5 [11].…”