Abstract
High-level protein expression is an important means of obtaining large amounts of viral proteins to investigate further their biological properties. To express the membrane (M) protein of SARS-CoV at high-level in vitro, the M gene fragment was amplified and cloned it into the Pichia Pastoris expression vector pPICZalphaA. SDS-PAGE and Western blotting analysis of the induced products of recombinant yeast transformant indicated that successful high-level expression of M protein was achieved, and that the expression product was similar antigenically to the natural protein. Purified recombinant M protein was used subsequently as an ELISA antigen for detection of eight serum samples screened previously by whole virus ELISA and immunofluorescence assay, and consistent results were obtained. These findings suggest that the recombinant M protein may be useful as a diagnostic reagent.