Regulation of neurogenesis by two-hour cycle biological clock

在胚胎神经干细胞中，Hes 1表达以约两小时的周期振荡，并且Hes 1振荡驱动原神经基因Ngn 2和Notch配体Dll 1的振荡表达。Dll 1振荡导致Notch信号传导的相互激活和神经干细胞的维持。当Hes 1表达消失时，Ngn 2以持续的方式表达，从而促进神经元分化。在成人大脑中，来自神经干细胞的神经发生是必不可少的，并且神经干细胞由Notch-Hes通路维持。这些结果揭示了节律基因Hes 1在胚胎和成体神经干细胞调控中的重要性。

In embryonic neural stem cells, Hes1 expression oscillates with a period of about two hours, and Hes1 oscillations drive oscillatory expression of the proneural gene Ngn2 and the Notch ligand Dll1. Dll1 oscillations lead to mutual activation of Notch signaling and maintenance of neural stem cells. When Hes1 expression disappears, Ngn2 is expressed in a sustained manner, thereby promoting neuronal differentiation. In the adult brain, neurogenesis from neural stem cells is essential, and neural stem cells are maintained by the Notch-Hes pathway. These results revealed the significance of the rhythmic gene Hes1 in regulation of embryonic and adult neural stem cells.