Fibroblast Growth Factor Receptor 2 Plays an Essential Role in Telencephalic Progenitors

We used loss-of-function analysis to determine the role of fibroblast growth factor receptor 2 (FGFR2) in telencephalic progenitors, and also to examine interactions between FGFR and Notch signaling. While the telencephalon of FGFR2 mutants appears grossly normal, mutant telencephalic progenitors exhibit altered proliferative behavior in vivo and in vitro. Based upon our prior finding that Notch1 activation increased neurosphere frequency in FGF2, we tested whether this effect is mediated by FGFR1 or FGFR2. We found that Notch1 activation increased neurosphere frequency in cells mutant for either FGFR1 or FGFR2, but had no effect on the reduced size of neurospheres mutant for those receptors. Additional analyses revealed biochemical changes in the adult neocortex mutant for the IIIc isoform of FGFR2, and essential roles for FGFR2 in nasopharynx, eyelid, and cornea development.