a study on the virus-like particle formation of hepatitis e virus orf2 and rotavirus nsp4 protein in the eukaryotic and prokaryotic expression systems

Background: hepatitis e virus (hev) is able to induce fulminant hepatitis e infection in immunosuppressed individuals. previous studies showed that the baculovirus expression system (bes) could be used for developing hepatitis e virus-like particles (vlps). objectives: in the present study, the formation of vlps of the recombinant proteins of hev truncated open reading frame 2 (orf2; 112 - 607) and rotavirus non-structural protein 4 (nsp4) (osu-a) were investigated in bes and escherichia. coli. methods: to construct vlps, the truncated orf2-nsp4 protein was expressed in bes. the expression of protein was confirmed by western blot. this protein was expressed in e. coli. the truncated orf2-nsp4 gene was subcloned in pet28a, and then transformed into e. coli dh5 . the confirmed colonies were transformed into e. coli bl21. the solubility of protein were checked by sds-page and western blot analysis. in the final step, to verify the vlp formation in bes and e. coli, the recombinant proteins were stained with 2% uranyl acetate and checked by transmission electron microscopy (tem). results: the 75 kda truncated orf2-nsp4 protein was successfully expressed in sf9 cells, assembled, and formed vlp according to tem results. in the prokaryotic expression system (e. coli), the orf2-nsp4 gene was successfully subcloned and expressed in bl21 but vlp was not detected in tem analysis. conclusions: the truncated orf2-nsp4 vlp were efficiently expressed in the sf9 cells, as a potential mucosal vaccine against hev and rotavirus. in the prokaryotic expression system (e. coli), the orf2-nsp4 gene was successfully expressed.