[Prokaryotic expression and identification of S-dsRNA gene from Cryptosporidium parvum virus].

To clone and express S-dsRNA gene of Cryptosporidium parvum virus, and investigate the reactogenicity of the recombinant. Total RNA was extracted from Cryptosporidium parvum and S-dsRNA gene was amplified by RT-PCR. The PCR product was cloned into pET-28a(+) expression vector. The recombinant plasmid pET-28a(+)-S was transformed into E. coli BL21 (DE3) and induced with IPTG. The expression situation of recombinant protein was analyzed by SDS-PAGE. Its reactogenicity was examined by Western blotting analysis. pET-28a (+)-S was identified by PCR and double endonuclease digestion. SDS-PAGE result showed that the recombinant protein (M, 37,000) was expressed in the form of inclusion body. High level expression of recombinant protein was found at 1 mmol/L IPTG condition after incubation at 37 degrees C for 4 h and reached up to 72.6% of the total protein. The protein was recognized by the antisera from mice immunized with antigens from Cryptosporidium parvum oocysts. The S-dsRNA gene of Cryptosporidium parvum virus has been expressed with adequate reactogenicity.