Subcellular and developmental expression of alternatively spliced forms offibroblast growth factor 14

Fibroblast growth factors (FGFs) 11-14 comprise a subfamily of FGFs with po orly defined biological function. Here we characterize two isoforms of FGF1 4 (FGF14-1a and FGF14-1b) that result from the alternative usage of two dif ferent first exons. We demonstrate that these isoforms have differential su bcellular localization and that they are differentially expressed in variou s adult tissues. Using in situ hybridization we show that Fgf14 is widely e xpressed in brain, spinal cord, major arteries and thymus between 12.5 and 14.5 days of mouse embryonic development. We also show that during cerebell ar development, Fgf14 is first observed at postnatal day 1 in post mitotic granule cells, and later in development, in migrating and post migratory gr anule cells. The developmental expression pattern of Fgf14 in the cerebellu m is complementary to that of Math1, a marker for proliferating granule cel ls in the external germinal layer. (C) 2000 Elsevier Science ireland Ltd. A ll rights reserved.