Molecular cloning and expression of mouse Wnt14, and structural comparison between mouse Wnt14-Wnt3a gene cluster and human WNT14-WNT3A gene cluster

Glycoprotein WNTs play key roles in carcinogenesis and embryogenesis. Human WNT14 and WNT3A genes are clustered in human chromosome 1q42 region with an interval of about 58 kb. Here, mouse Wnt14 was isolated to compare the structure of human WNT14-WNT3A gene cluster with that of mouse Wnt14-Wnt3a gene cluster. Mouse Wnt14 showed 98.1% total-amino-acid identity with human WNT14, and 61.9% total-amino-acid identity with human WNT14B/WNT15. Mouse Wnt14 mRNA was expressed in adult brain, lung, skeletal muscle, heart, and 17-day embryo. Mouse Wnt14 and Wnt3a genes were clustered in head-to-head manner with an interval of about 16 kb. Exon-intron structures were well conserved between human WNT14-WNT3A gene cluster and mouse Wnt14-Wnt3a gene cluster. Capicua-related sequence and AK024248-related sequence were identified in the intergenic region of human Wnt14-Wnt3a gene cluster as well as in other human chromosomal loci, but not in that of mouse Wnt14-Wnt3a gene cluster. Capicua-related sequences were pseudogenes derived from Capicua gene on human chromosome 19q13. Capicua pseudogene and AK024248-related sequence were clustered in tail-to-tail manner with interval ranging from 2.2 to 11.0 kb. AK024248-related sequences in several human genome draft sequences were truncated in the 3'-portion compared with that in the intergenic region of human WNT14-WNT3A gene cluster. This is the first report on structural comparison of WNT gene clusters in human genome and in mouse genome.