关键词: 日本血吸虫, 弹性蛋白酶基因, 原核表达

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 sporosysts， with Mr 31 000. 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.

Key words: Schistosoma japonicum, Elastase gene, Prokaryotic expression