Noctor Stephen C, Flint Alexander C, Weissman Tamily A, Wong Winston S, Clinton Brian K, Kriegstein Arnold R
Department of Neurology, Columbia College of Physicians and Surgeons, New York, New York 10032, USA.
J Neurosci. 2002 Apr 15;22(8):3161-73. doi: 10.1523/JNEUROSCI.22-08-03161.2002.
The embryonic ventricular zone (VZ) of the cerebral cortex contains migrating neurons, radial glial cells, and a large population of cycling progenitor cells that generate newborn neurons. The latter two cell classes have been assumed for some time to be distinct in both function and anatomy, but the cellular anatomy of the progenitor cell type has remained poorly defined. Several recent reports have raised doubts about the distinction between radial glial and precursor cells by demonstrating that radial glial cells are themselves neuronal progenitor cells (Malatesta et al., 2000; Hartfuss et al., 2001; Miyata et al., 2001; Noctor et al., 2001). This discovery raises the possibility that radial glia and the population of VZ progenitor cells may be one anatomical and functional cell class. Such a hypothesis predicts that throughout neurogenesis almost all mitotically active VZ cells and a substantial percentage of VZ cells overall are radial glia. We have therefore used various anatomical, immunohistochemical, and electrophysiological techniques to test these predictions. Our data demonstrate that the majority of VZ cells, and nearly all mitotically active VZ cells during neurogenesis, both have radial glial morphology and express radial glial markers. In addition, intracellular dye filling of electrophysiologically characterized progenitor cells in the VZ demonstrates that these cells have the morphology of radial glia. Because the vast majority cycling cells in the cortical VZ have characteristics of radial glia, the radial glial precursor cell may be responsible for both the production of newborn neurons and the guidance of daughter neurons to their destinations in the developing cortex.
大脑皮层的胚胎脑室区（VZ）包含正在迁移的神经元、放射状胶质细胞以及大量产生新生神经元的循环祖细胞。一段时间以来，人们认为后两类细胞在功能和解剖结构上是不同的，但祖细胞类型的细胞解剖结构一直没有得到很好的界定。最近的几份报告对放射状胶质细胞和前体细胞之间的区别提出了质疑，这些报告表明放射状胶质细胞本身就是神经元祖细胞（Malatesta等人，2000年；Hartfuss等人，2001年；Miyata等人，2001年；Noctor等人，2001年）。这一发现增加了放射状胶质细胞和VZ祖细胞群体可能是同一解剖和功能细胞类别的可能性。这样的假设预测，在整个神经发生过程中，几乎所有有丝分裂活跃的VZ细胞以及总体上相当比例的VZ细胞都是放射状胶质细胞。因此，我们使用了各种解剖学、免疫组织化学和电生理学技术来检验这些预测。我们的数据表明，大多数VZ细胞以及神经发生过程中几乎所有有丝分裂活跃的VZ细胞都具有放射状胶质细胞的形态并表达放射状胶质细胞标记物。此外，对VZ中经电生理学鉴定的祖细胞进行细胞内染料填充显示，这些细胞具有放射状胶质细胞的形态。由于皮质VZ中绝大多数循环细胞具有放射状胶质细胞的特征，放射状胶质前体细胞可能既负责新生神经元的产生，又负责将子代神经元引导至发育中皮层的目的地。
