Preliminary Characterization And Expression Of A Vasa-like Gene In Schistosoma Japonicum

Objective To investigate the transcription and expression pattern of Vasa-like gene in Schistosoma japonicum, a series of experiments, from gene cloning to Sj-Vasa protein expressing and locolization detection, were carried out, which may provide novel approach to develop new vaccines for schistosomiasis.Method The full-length sequence of Vasa-like gene of S. japonicum were amplified, using cDNA as PCR template. Phylogenetic analysis was performed based on Vasa gene of S. japonicum using Bayesian method. Truncated SjVasa which contains a highly conserved DEAD-BOX motif was expressed prokaryoticly and further used for polyclonal antibody production. Meanwhile, we utilized Quantitative real-time PCR and Western-blot to evaluate the expression characteristics of the S. japonicum Vasa gene (Sj-vasa) during different life stages.Results Full-length S. japonicum Vasa gene (2,820nucleotides) was obtained through PCR, which has been submitted to GeneBank (GenBank accession number: AFC17964.1).Quantitative Real-time PCR analysis revealed that Sj-Vasa transcription exhibited high level at day24in both male and female worms, compared to other adult stages. In the same stage the expression of the femle is always higer than male. Furthermore, We generated an anti-Vasa polyclonal antibody and the results of Western-blot showed that the Vasa protein is present throughout the S. japonicum life cycle, the vasa protein levels was strongly correlated with the mRNA levels.The results of immunohistochemistry show that Vasa protein mainly distributed in the vitelline gland, ovarian cell, body wall, male reproductive cells and metabolic sites of skin tissue.Conclusion Both the transcription and expression profile of SjVasa suggested that this protein may play a regulatory role in the development of germ cells in S. japonicum.