STRUCTURE AND EXPRESSION OF A NOVEL FIBROBLAST GROWTH-FACTOR, FGF-17,PREFERENTIALLY EXPRESSED IN THE EMBRYONIC BRAIN

We isolated the cDNA encoding a novel member (216 amino acids) of the fibroblast growth factor (FGF) family from rat embryos. As this protei n is the 17th documented member of the FGF family, we tentatively term ed it FGF-17. We have also determined the structures of mouse and huma n FGF-17 with high amino acid identity (100 and 98.6%) to rat FGF-17, respectively. Among FGF family members, FGF-17 is most similar (53.7% amino acid identity) to FGF-8. FGF-17 has a typical signal sequence at its amino terminus. As expected, recombinant rat FGF-17 was efficient ly secreted by High Five insect cells infected with recombinant baculo virus containing the cDNA indicating that FGF-17 is a secreted protein . FGF-17 mRNA of similar to 2.1 kb was detected in rat embryos at E14. 5, but not at E10.5 and E19.5 by Northern analysis. The mRNA was found to be preferentially expressed in the neuroepithelia of the isthmus a nd septum of the rat embryonic brain at E 14.5 by in situ hybridizatio n. The present results indicate that FGF-17 might be a novel secreted signaling molecule in the induction and patterning of the embryonic br ain. (C) 1998 Academic Press.