Mione M C, Cavanagh J F, Harris B, Parnavelas J G
Department of Anatomy and Developmental Biology, University College London, London WC1E 6BT, United Kingdom.
J Neurosci. 1997 Mar 15;17(6):2018-29. doi: 10.1523/JNEUROSCI.17-06-02018.1997.
Two different modes of cell division are adopted by progenitor cells to generate the neurons and glia of the cerebral cortex: they either divide symmetrically to generate other progenitors or a pair of postmitotic cells or divide asymmetrically to generate both a progenitor and a postmitotic cell. In this study we used a lineage marker, the BAG retrovirus, in embryonic day 16 rats in combination with bromodeoxyuridine (BrdU) to identify patterns of cell generation in the cerebral cortex, and investigated the relationship between the phenotype of cells and the history of their lineages. The location, phenotype and birth order of clonally related cells were studied in the subsequent 3 weeks. Only pyramidal neurons and/or astrocytes formed discrete clusters in which several generations of family members were present, whereas nonpyramidal neurons were found exclusively in pairs or as single cells. Analysis of BrdU levels in these cells showed that nonpyramidal neurons were originally part of larger clones and were found dispersed in the neocortex because of tangential migration of their progenitors, dispersion of postmitotic cells, or death of clonal relatives. These results suggest that both symmetrical and asymmetrical division can be adopted by progenitor cells to generate cortical neurons and glial cells and that cell extrinsic events contribute to the isolation of nonpyramidal neurons.
它们要么对称分裂以产生其他祖细胞或一对有丝分裂后细胞，要么不对称分裂以产生一个祖细胞和一个有丝分裂后细胞。在本研究中，我们在胚胎第16天的大鼠中使用谱系标记物BAG逆转录病毒并结合溴脱氧尿苷（BrdU）来识别大脑皮层中的细胞生成模式，并研究细胞表型与其谱系历史之间的关系。在随后的3周内研究了克隆相关细胞的位置、表型和出生顺序。只有锥体神经元和/或星形胶质细胞形成离散的簇，其中存在几代家族成员，而非锥体神经元仅成对或单个存在。对这些细胞中BrdU水平的分析表明，非锥体神经元最初是较大克隆的一部分，由于其祖细胞的切向迁移、有丝分裂后细胞的分散或克隆亲属的死亡而分散在新皮层中。这些结果表明，祖细胞可以采用对称和不对称分裂来生成皮层神经元和神经胶质细胞，并且细胞外在事件有助于非锥体神经元的分离。
