Cloning and Expression of SARS Coronavirus M gene

The full-length gene of membrane protein ( M )of SARS coronavirus (SARS-CoV) was cloned using RT-PCR from the Vero-E6 cells infected with SARS-CoV (GD322 strain) and inserted into the multi-cloning site of the pPICZαB vector. The recombinant plasmid was transtormed into P. pastoris strain X-33 by electroporation and selected by Zeocin. Mut phenotype determination was performed on the yeast transformants and then expression of Mut~+ colonies were induced by methanol. The expressed products were analyzed by SDS-PAGE and Western blotting. Secreted expression was performed by screening Mut~+ colonies in the yeast (transformants). The molecular mass of the recombinant M protein was approximately 65 kDa and 42 kDa and secreted into culture medium when induced with methanol. The expressed protein was able to (react) with SARS convalescence polyclonal antibody.