柔嫩艾美耳球虫(E.tenella)杂交株F2 SO7基因ORF的克隆与表达

The SO7 gene of E. tenella F2 hybrid strain [F1(JL×HB)×SD] was amplified from E. tenella RNA extracted from sporulating oocysts by RT-PCR and cloned into pMD18-T vector to produce plasmid pMD18-SO7. The PCR product was approximately 651 bp containing mainly AGC repetitive sequence and encoded for a polypeptide of 216 amino acid with a molecular weight of 22.4 Ku. It shared 97.7% nucleotide homology and 94.9% amino acid identity with the published SO7 sequences. The SO7 gene was subcloned from pMD18-SO7 into the expression vector pGEX-6p-1 and the resultant porkaryotic expression vector pGEX-6p-SO7 was transformed into E. coli BL21 (DE3). Expression of SO7 was induced by IPTG and analysed by SDS-PAGE and Western blot. The expressed protein had a molecular weight of approximately 43.8 Ku and possessed antigenicity of E. tenella. The results laid foundation for the further studies on the subunit vaccine and SO7 DNA vaccine for prevention of E. tenella.