MOLECULAR CLONING AND PROKARYTIC EXPRESSION OF Cryptosporidium parvumSURFACE ANTIGEN P23 GENE IN Escherichia coliBL21

Total DNA was extracted from cDNA library of Cryptosporidium parvum and the DNA fragment encoding mature peptide of p23 gene was amplified by PCR method.The fragment was cloned into plasmid pGEX-4T-2,forming the recombinant prokaryotic expression vector(pGEX-p23) which was identified by EcoR I and Sal I digestion and sequence analysis.The E.coli BL21 containing recombinant plasmid was induced by IPTG to express fusion protein.SDS-PAGE and Western blot were performed to identify the recombinant protein.SDS-PAGE analysis showed that there was a new protein band,which is of 47kDa.Western blot proved that the fusion protein could be specifically recognized by anti-p23 antibody and it is the basis for the study on biological activities of P23 and for possible clinic application in the future.