Cloning and expression characteristics of ES24 gene in Haemonchus contortus

A gene fragment at a length of 670 bp was produced by RT-PCR,using a pair of primers based on the ES24 sequence(No.U64793.1) of Haemonchus contortus.Then this fragment was cloned into pMD18-T vector,sequenced and analysed.It was founded that the gene was 96%~98% similar with the gene of H.contortus ES24 available in the GenBank.The prokaryotic expression plasmid pET28/ES24 was constructed by cloning the ORF of ES24 into the vector pET28a(+).Then the recombinants were transformed into Escherichia coli BL21 and induced by isopropyl-B-D-thiogalactopyranoside(IPTG).The SDS-PAGE analysis showed that the recombinant protein was expressed with the molecular weight of 25 ku.The ES24 RNA levels in egg,the third stage larva(L3),adult male and female worms were detected by Real-time PCR.The result showed that ES24 was expressed at the highest level in the adult male worms and lowest in the L3.