Soluble Expression, Purification and Characterization of the VP3 of the
1st Serotype Bluetongue Virus
Abstract
Bluetongue (BT) is a non-contact infectious disease of domestic or wild
ruminants caused by the Bluetongue virus (BTV). It is transmitted by
Culicoides biting midges. BTV mainly infect sheep, and animals infected
with BTV usually show clinical symptoms such as fever, mucosal edema,
and ulcers. BTV virus is an icosahedral symmetric RNA virus with 27
different serotypes. BTV consists of 7 structural proteins (VP1-VP7) and
4 non-structural proteins (NS1, NS2, NS3/NS3a, NS4, NS5). The VP3
encoded by the L3 gene is relatively high conserved structural protein,
and constitute the inner symmetric icosahedral core shell of virus
particle. In this study, VP3 recombinant protein of bluetongue I virus
was successfully expressed and purified by prokaryotic expression
system. Moreover, to increase the amount of soluble protein, we used
chaperone protein ptf16 and two fusion proteins NusA and TRX. The
results show that chaperone protein can increase the solubility of VP3.
Then the expression conditions were optimized and VP3 was purified by
nickel affinity chromatography. The VP3 immunize Balb/c mice and the
results show that the serum titer is 1:1.28×105. In the Dot-ELISA assay,
we found recombinant protein VP3 react with the serum from immunized
mice by inactivate BTV-1. The results of IFA showed that the antibody
produced by immunized mice with recombinant protein VP3 could react with
the VP3 protein expressed in 293T cell. In conclusion, we expressed the
recombinant protein VP3 with the same conformation as eukaryotic
expression system and had same immunogenicity with inactivated virus,
which laid a foundation for further study on the structure and function
of BTV.