Comparative genomics on FGF16 orthologs.

We have previously reported comparative genomics analyses on FGF3, FGF4, FGF6, FGF7, FGF8, FGF10, FGF11, FGF17, FGF18, FGF19, FGF20, FGF22 and FGF23 genes. Here, we performed comparative genomics analyses on FGF1, FGF2, FGF5, FGF9, FGF12, FGF13, FGF14, FGF16 and FGF21 genes, and further characterized the FGF16 gene. Chimpanzee FGF16, chicken fgf16, and zebrafish fgf16 genes were identified within NW_121938.1, NW_060344.1, and CR855117.3 genome sequences, respectively. Chimpanzee FGF16 (207 aa), chicken fgf16 (207 aa), and zebrafish fgf16 (203 aa) showed 100%, 89.9%, and 79.2% total amino-acid identity with human FGF16. Because FGF16, FGF9, and FGF20 constitute FGF subfamily without N-terminal signal peptide, we next searched for uncharacterized FGF9 or FGF20 orthologs. Zebrafish fgf9 gene was identified within BX927112.11 genome sequence, and chicken fgf20 gene within NW_060349.1 genome sequence. Although N-terminal part was divergent, middle and C-terminal parts were well conserved among vertebrate FGF16, FGF9 and FGF20 orthologs. Phylogenetic analyses revealed that zebrafish fgf9 and fgf20 were more related to each other than to their chicken or mammalian orthologs. TCF/LEF binding site and TATA box were well conserved among the human FGF16, rat Fgf16, and mouse Fgf16 promoters. Because nuclear complex consisting of TCF/LEF (TCF1, TCF3, TCF4 or LEF1), beta-catenin, PYGO (PYGO1 or PYGO2) and Legless (BCL9 or BCL9L) binds to the TCF/LEF-binding site to up-regulate WNT/beta-catenin target genes, FGF16 gene was characterized as the evolutionarily conserved target of the WNT/beta-catenin signaling pathway, just like FGF18 and FGF20 genes. These facts indicate that FGF16, FGF18 and FGF20 are pharmacogenomics targets in the field of oncology and regenerative medicine.