Characterization and expression of a novel Frizzled 9 gene in Schistosoma japonicum.

Wnt signaling regulates a diverse array of eukaryotic development processes, which are mediated by the Frizzled family receptors. However, the role of this signaling pathway in the development of Schistosoma japonicum remains poorly understood. We isolated a novel S. japonicum Frizzled member (SjFz9), which encodes a 923 amino acid protein, sharing the general feature of Frizzled proteins. We investigated its mRNA and protein expression patterns during different life stages in definitive hosts. Quantitative real-time PCR analysis revealed that SjFz9 transcripts were highly expressed in the schistosomulum. In adult stages, SjFz9 expression exhibited high level at day 23 and day 42 in both male and female, compared to other adult stages. The immunohistochemical localization pattern of the SjFz9 protein showed a broad tissue distribution in the subtegumental musculature and acetabulum musculature of schistosomulum and adult worms. Furthermore, SjFz9 was found prominently expressed in the testes of the male and the ovary as well as the vitellarium of the female. Our data suggest that SjFz9 may be an important Wnt receptor with potential functions in regulating the cell differentiation and proliferation within the musculature, as well as the development of the reproductive organs of both sexes.