Qian X, Davis A A, Goderie S K, Temple S
Department of Pharmacology and Neuroscience, Albany Medical College, NY 12208, USA.
Neuron. 1997 Jan;18(1):81-93. doi: 10.1016/s0896-6273(01)80048-9.
The embryonic cerebral cortex contains a population of stem-like founder cells capable of generating large, mixed clones of neurons and glia in vitro. We report that the default state of early cortical stem cells is neuronal, and that stem cells are heterogeneous in the number of neurons that they generate. In low fibroblast growth factor (FGF2) concentrations, most maintain this specification, generating solely neuronal progeny. Oligodendroglial production within these clones is stimulated by a higher, threshold level of FGF2, and astrocyte production requires additional environmental factors. Because most cortical neurons are born before glia in vivo, these data support a model in which the scheduled production of cortical cells involves an intrinsic neuronal program in the early stem cells and exposure to environmental, glia-inducing signals.
胚胎期大脑皮层包含一群干细胞样的奠基细胞，这些细胞在体外能够生成大量混合的神经元和神经胶质细胞克隆。我们报告称，早期皮层干细胞的默认状态是神经元状态，并且干细胞在生成神经元的数量上是异质的。在低浓度成纤维细胞生长因子（FGF2）条件下，大多数细胞维持这种分化状态，仅产生神经元后代。这些克隆体内少突胶质细胞的产生受到较高阈值水平的FGF2刺激，而星形胶质细胞的产生则需要额外的环境因素。由于大多数皮层神经元在体内是在神经胶质细胞之前产生的，这些数据支持了一种模型，即皮层细胞的定时产生涉及早期干细胞中的固有神经元程序以及暴露于环境中诱导神经胶质细胞的信号。
