Abstract: Total RNA was extracted from adult Boophilus microplus. RT-PCR was used to amplify the gene and the fragment was subcloned into the expression vector pET-28a. The cloned gene was expressed in E. coli Rosseta（DE3）, induced by IPTG， and identified by SDS-PAGE. The results showed that the triosephosphate isomerase （tim） gene of B. microplus has 750 bp and encodes 249 amino acids （GenBank No. JX112888）. The cloned tim gene shares 99% homology with that in tick embryos. The relative molecular weight （M_r） of the expressed recombinant protein is about 27 000.

Key words: Boophilus microplus, Triosephosphate isomerase, Cloning, Expression