Molecular cloning and characterization of human WNT8A.

WNT - beta-catenin - TCF pathway is involved in carcinogenesis and fetal development. Xenopus wnt-8 is one of the most potent Wnts with the capacity to activate beta-catenin - TCF pathway in the Xenopus axis duplication assay. Here, we have cloned and characterized WNT8A, a novel human homologue of Xenopus wnt-8. The WNT8A gene, consisting of at least 6 exons, was found to encode a 351-amino-acid polypeptide with the N-terminal signal peptide, three N-linked glycosylation sites, and conserved amino-acid residues of the WNT family. WNT8A showed 63.2% total-amino-acid identity to WNT8B. C-terminal region of WNT8A, WNT8B, WNT2, WNT2B1 and WNT2B2 were longer than that of other WNTs. Among various normal human tissues and 34 human cancer cells lines, the 3.5-kb WNT8A mRNA was detected only in a human teratocarcinoma cell line NT2. These results strongly suggest that WNT8A might be implicated in development of early embryos as well as germ cell tumors through activation of the WNT - beta-catenin - TCF pathway.