STRUCTURE AND SEQUENCE OF HUMAN FGF8

Recent evidence indicates that Fgf8 is expressed during vertebrate dev elopment in multiple locations involved in the patterning and outgrowt h of important embryo structures. Cloning and analysis of the murine g ene revealed at least eight potential protein isoforms that share a co mmon carboxyl region, encoded by exons 2 and 3, but possess different amino termini, generated by alternative splicing of RNA encoded by mul tiple 5' exons (exons 1A, 1B, 1C, and 1D). We now report the cloning a nd sequence of the human FGF8 gene. Human FGF-8 isoforms are identical to their murine counterparts in the common carboxyl region. Four of t he human isoforms are identical to, or very similar to, the murine iso forms in the amino termini, However, four of the potential murine isof orms do not have corresponding human isoforms due to marked sequence d ivergence, leading to a blocked reading frame in exon 1B of FGF8. The lack of the four murine isoforms in humans raises the question of thei r function in murine development. (C) 1996 Academic Press, Inc.