脳神経科学を社会へ還流する教育研究拠点　東北大脳科学グローバルCOE

Tomoko Iwata, （University of Glasgow）

Fibroblast Growth Factors (Fgfs) are important regulators of　cerebral cortex growth and morphogenesis. While Fgf8/17 specifies positional identity of the frontal cortex, the factor　that regulates the caudal cortex formation is unknown. Here　we report a new function of Fgf signaling transduced through　Fgf receptor 3 (Fgfr3). In mice with constitutively active　Fgfr3　conditionally expressed under brain-specific Cre,　s　urface area of the caudal cortex was massively enlarged, while that of the rostral cortex remained similar. Shortening　of　cell cycle length in caudal cortical progenitors is likely to have caused this phenotype. Furthermore, thickness of the caudal cortex was significantly increased, which was correlated with increased number of Tbr2+ intermediate progenitors at the end of the embryonic development, consistent with prolongation of neurogenesis. Selective occipitotemporal surface expansion reflects the characteristics of cortical malformation in human Thanatophoric Dysplasia caused by FGFR3 mutations, indicating the relevant role of FGFR3 in human cortical development.