Sato Tatsuya, Kikkawa Takako, Saito Tetsuichiro, Itoi Keiichi, Osumi Noriko
Department of Developmental Neuroscience, Graduate School of Medicine, 980-8575, Tohoku University, Sendai, Japan.
Frontier Research Institute for Interdisciplinary Sciences, 980-8578, Tohoku University, Sendai, Japan.
Dev Growth Differ. 2017 Dec;59(9):701-712. doi: 10.1111/dgd.12411. Epub 2017 Nov 10.
The anterior part of the embryonic telencephalon gives rise to several brain regions that are important for animal behavior, including the frontal cortex (FC) and the olfactory bulb. The FC plays an important role in decision-making behaviors, such as social and cognitive behavior, and the olfactory bulb is involved in olfaction. Here, we show the organizing activity of fibroblast growth factor 8 (Fgf8) in the regionalization of the anterior telencephalon, specifically the FC and the olfactory bulb. Misexpression of Fgf8 in the most anterior part of the mouse telencephalon at embryonic day 11.5 (E11.5) by ex utero electroporation resulted in a lateral shift of dorsal FC subdivision markers and a lateral expansion of the dorsomedial part of the FC, the future anterior cingulate and prelimbic cortex. Fgf8-transfected brains had lacked ventral FC, including the future orbital cortex, which was replaced by the expanded olfactory bulb. The olfactory region occupied a larger area of the FC when transfection efficiency of Fgf8 was higher. These results suggest that Fgf8 regulates the proportions of the FC and olfactory bulb in the anterior telencephalon and has a medializing effect on the formation of FC subdivisions.
胚胎端脑的前部发育出几个对动物行为很重要的脑区，包括额叶皮质（FC）和嗅球。FC在决策行为中起重要作用，如社交和认知行为，而嗅球参与嗅觉。在此，我们展示了成纤维细胞生长因子8（Fgf8）在前脑区域化中的组织活性，特别是在FC和嗅球的区域化中。在胚胎第11.5天（E11.5）通过子宫外电穿孔法在小鼠端脑的最前部错误表达Fgf8，导致背侧FC亚区标记物向外侧移位，以及FC背内侧部分（未来的前扣带回和前额叶皮质）向外侧扩展。Fgf8转染的大脑缺少腹侧FC，包括未来的眶额皮质，其被扩展的嗅球所取代。当Fgf8的转染效率较高时，嗅觉区域占据了FC的更大面积。这些结果表明，Fgf8调节前脑区域中FC和嗅球的比例，并对FC亚区的形成具有向内侧化的作用。
