Isolation of two novel WNT genes, WNT14 and WNT15, one of which (WNT15) is closely linked to WNT3 on human chromosome 17q21.

The Wnt gene family consists of at least 15 structurally related genes that encode secreted extracellular signaling factors. Wnt proteins function in a range of critical developmental processes in both vertebrates and invertebrates and are implicated in regulation of cell growth and differentiation in certain adult mammalian tissues, including the mammary gland. We have isolated a number of WNT sequences from human genomic DNA, two of which, designated WNT14 and WNT15, represent novel members of the Wnt gene family. We also isolated WNT sequences from human mammary cDNA and present evidence that WNT13 is expressed in human breast tissue, in addition to those previously described. WNT14 and WNT15 appear to have originated from an ancestral branch of the Wnt gene family that also includes the Wnt9 sequences found in jawless and cartilaginous fishes. A Wnt14 cDNA was also isolated from chicken and a partial Wnt15 sequence from mouse. We show that human WNT14 maps to chromosome 1 and that WNT15 maps distal to BRCA1 on chromosome 17q21, where it lies within 125 kb of another WNT family member, WNT3.