Molecular cloning and characterization of WNT14B, a novel member of the WNT gene family.

WNT14B was cloned and characterized in this study. WNT14B encoded 357-amino acid WNT family protein with the signal peptide and an N-linked glycosylation site. WNT14B was most homologous to WNT14 (61.4% total amino acid identity). WNT15 cDNA fragment previously isolated by another group corresponds to a part of ORF of the WNT14B cDNA (codon 216-335). Exon-intron boundaries were conserved between WNT14B and WNT14 genes. WNT14B and WNT3 genes were clustered in the human chromosome 17q21 region in head to head manner. Intergenic region between WNT14B and WNT3 genes was about 33 kb in size. The 6.6-kb WNT14B mRNA was moderately expressed in fetal kidney and adult kidney. Although WNT14B mRNA was not detected in fetal brain and adult brain by northern blot analyses, WNT14B mRNA was detected in brain, especially in occipital lobe, by RNA dot blot analysis. Among 48 human cancer cell lines derived from various tissues, WNT14B was expressed in a teratocarcinoma cell line NT2 with the potential to differentiate into neuronal cells. WNT14B mRNA was significantly up-regulated by all-trans retinoic acid in NT2 cells. These results strongly suggest that WNT14B might be implicated in the early process of neuronal differentiation of NT2 cells induced by retinoic acid.