Cloning and sequence analysis of the antigen B sub-units from Echinococcus granulosus isolate from Xinjiang, China

Objective To clone the subunits of AgB antigen gene family of Echinococcus granulosus ( Eg),analyze genetic variability of the gene sequences.Methods Specific primers were designed based on the published references.Total RNA was extracted from E.granulosus protoscoleces collected from a sheep hydatid cyst from Xinjiang,the fragments of three AgB subunits gene were obtained by RT-PCR using the extracted RNA and cloned into TA vector for sequencing.The online sequence analysis systems such as Bdoedit software,Blastn and clusterW2 were used for the analysis.Results Three AgB gene subunits were cloned from E.granulosus,respectively,and identified by sequencing.Sequence homology analysis indicated that the EgAgB subunits were variable.Sequence alignment of the nucleic acid sequences of three AgB subunits gene showed that the identity ranged from 43％ to 60％,alignment of the putative amino acid sequences of three AgB subunits gene ranged from 30％ to 42％.Conclusion The EgAgB subunits showed a high degree of genetic variability. Key words: Echinococcus granulosus; AgB subunits gene; Gene cloning; Sequence analysis