Abstract: 　Objective To conduct cloning, sequencing and expression of Trichinella spiralis ES antigen p49 gene. Methods RT-PCR was used to amplify the specific gene fragment from the total RNA of Trichinella spirais larvae. The PCR product was ligated to the T-vector and the recombinant plasmid was verified by sequencing. T-p49 and pGE-4T-3 were treated by both BamHI and XhoI. The ligation reaction was catalyzed by T4 DNA ligase. Results The p49 gene was cloned by using RT-PCR. Sequence analysis showed that the p49 gene obtained was consistent to the p49 sequence reported in the database. The expressed protein was shown as a new band at SDS-PAGE. BLAST analysis demonstrated that this p49 gene was 99% identical to the p49 gene reported and to the 43 kDa secreted glycoprotein gene in the database. Conclusion p49 gene from Trichinella spiralis larvae was cloned, sequenced and expressed.

Key words: Trichinella spiralis, p49 gene, gene cloning, expression