[Cloning, expression of Schistosoma japonicum elastase gene and its stage-specific transcription].

ABSTRACT

OBJECTIVE: To clone, express and purify Schistosoma japonicum elastase-2b gene (SjCE-2b), and analyze its stage-specific transcription. and expression. METHODS: The coding sequence of the Sj gene was predicted, and a phylogenetic tree of Sj elastase was drawn. RT-PCR and Western blot were used to investigate the differential transcription and expression of SjCE-2b gene during the developmental stages. The SjCE-2b gene obtained by RT-PCR was subcloned into pET28b, and expressed in E.coli (rSjCE-2b). The expressed protein was purified with His Tag affinity chromatography. Western blotting was used to investigate the immunogenicity. RESULTS: RT-PCR showed specific bands in sporocysts, eggs and adult worms, while Western blot showed that the recombinant protein (rSjCE-2b) existed only in cercariae and sporocysts, with Mr 31000. The expression vector of SjCE-2b/pET28b was constructed and expressed in E. coli. The recombinant protein rSjCE-2b was specifically recognized by the S. japonicum-infected rabbit serum. CONCLUSION: The transcript of S. japonicum elastase-2b gene was found in sporocysts, eggs and adult worms, and this gene might be a potential candidate for vaccine, for drug and diagnosis target.