Molecular cloning and characterization of human WNT7B

WNT signaling molecules are implicated in carcinogenesis and embryogenesis. Only partial coding sequence of human WNT7B is reported so far, and human genome draft sequence corresponding to the WNT7B gene in human chromosome 22q13 region is not available at present. Here, we have cloned human WNT7B cDNAs, spanning the complete coding sequence, by using rapid amplification of cDNA ends (RACE) and cDNA-PCR. WNT7B encoded a 349-amino-acid polypeptide with three N-linked glycosylation sites and consensus amino-acid residues conserved among members of the WNT family. WNT7B showed 77.1% total-amino-acid identity with WNT7A. The 4.0-kb WNT7B was moderately expressed in fetal brain, weakly expressed in fetal lung and kidney, and faintly expressed in adult brain, lung and prostate. Expression levels of WNT7B mRNA in a lung cancer cell line A549, esophageal cancer cell lines TE2, TE3, TE4, TE5, TE6, TE7, TE10, TE12, a gastric cancer cell line TMK1, and pancreatic cancer cell lines BxPC-3, AsPC-1 and Hs766T were significantly higher than that in fetal kidney. In addition, WNT7B was up-regulated in 5 out of 10 cases of primary gastric cancer. These results strongly suggest that WNT7B might play important roles in various types of human cancer.