Comparative genomics on FGF20 orthologs.

We cloned and characterized human FGF20 in August, 2000. Ohmachi et al claimed the same gene as a novel FGF family member in October, 2000, and Jeffers et al in April, 2001. FGF20 is up-regulated in colorectal cancer due to the activation of WNT/beta-catenin pathway. FGF20 is applicable as the mucosal protective agent for inflammatory bowel disease and chemotherapy/radiation-induced oral mucositis, and also as the inducer of dopaminergic neurons for Parkinson's disease. FGF20 is a target of pharmacogenomics in the field of oncology and regenerative medicine. Here, comparative genomics analyses on FGF20 orthologs were performed. Zebrafish fgf20 gene, consisting of three exons, was located within BX323810.8 genome sequence. Zebrafish fgf20 (208 aa) showed 76.9%, 76.4%, 76.0% and 75.5% total-amino-acid identity with human FGF20, Xenopus fgf20, rat Fgf20 and mouse Fgf20, respectively. Fgf20 orthologs were well conserved among vertebrates. Human FGF20 gene was linked to EFHA2 gene in head-to-head manner with an interval of about 25 kb. FGF20-EFHA2 locus at human chromosome 8p22 and FGF9-EFHA1 locus at human chromosome 13q12.11 were paralogous regions (paralogons) within the human genome. The 5'-flanking promoter region, exonic regions except 3'-UTR, and middle regions within intron 1 were conserved between human FGF20 and mouse Fgf20 genes. Double TCF/LEF binding sites, double EVI1-binding sites, TGIF, PAX4, E47 and AREB6-binding sites were conserved between human FGF20 promoter and mouse Fgf20 promoter.