Expression and Bioactivity Identification of eis Gene of Mycobacterium bovis in Mycobacterium smegmatis

This study was aimed to construct a shuttle expression vector of Mycobacterium bovis(M.bovis) eis gene and identify its bioactivity in recombinant Mycobacterium smegmatis (M.smegmatis). M.bovis eis gene was cloned by PCR and the shuttle expression vector pMV261-Mbeis was constructed, then it was identified by double digestion and sequencing. The recombinant plasmid was transformed into M.smegmatis mc²155 by electroporation. The expression of M.bovis eis gene in M.smegmatis was detected by SDS-PAGE and Western blotting, and the amino acids sequence of the target protein was identified by mass spectrometry. The growth curve of recombinant M.smegmatis mc²155 containing pMV261-Mbeis was successfully constructed.The results showed that pMV261-Mbeis did not affect the growth of M. smegmatis in vitro. The results of SDS-PAGE and Western blotting confirmed that the M. bovis eis gene expressed the eis protein which was about 44 ku in M. smegmatis. Mass spectrometry proved that the protein was the eis protein of M. bovis.The expression vector pMV261-Mbeis was successfully constructed and the expressed recombinant protein was proved to be have biological activities in M. smegmatis, which laid a foundation for the further study of the function of eis protein in M. bovis.