Ware M L, Tavazoie S F, Reid C B, Walsh C A
Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Institutes of Medicine, Boston, MA 02115, USA.
Cereb Cortex. 1999 Sep;9(6):636-45. doi: 10.1093/cercor/9.6.636.
Cell lineage analysis in rodents has shown that the cerebral cortex is formed from both widespread and large radial clustered clones representing partly distinct lineages and producing differing cell types. Since previous cell lineage analysis of the ferret cortex using retroviral libraries showed that most neurons labeled at E33-E35 formed widespread clones, we determined whether clones labeled earlier in neurogenesis showed a greater tendency to form coherent radial clones. Clones labeled at E27-E29 occasionally consisted of widespread multineuron clones (13% of PCR-defined clones), but commonly consisted of small clusters of two to four neurons (65%). Moreover, 6/21 hemispheres contained a single, much larger (6-150 cells) radial cluster. Although large clusters were observed in 28% of experiments, they contained many neurons, accounting for 38% of retrovirally labeled cells. The large clusters showed at most few widely scattered sibling cells, either by histological analysis or by PCR analysis, suggesting that radial and widespread clones coexist but are lineally separate at early stages of corticogenesis. Coexistence of large radial and widespread neuronal clones appears to be an evolutionarily conserved mechanism for cortical neurogenesis.
对啮齿动物的细胞谱系分析表明，大脑皮层由广泛分布和大型放射状聚集的克隆形成，这些克隆代表部分不同的谱系并产生不同的细胞类型。由于先前使用逆转录病毒文库对雪貂皮层进行的细胞谱系分析表明，在E33 - E35标记的大多数神经元形成了广泛分布的克隆，我们确定在神经发生早期标记的克隆是否更倾向于形成连贯的放射状克隆。在E27 - E29标记的克隆偶尔由广泛分布的多神经元克隆组成（占PCR定义克隆的13%），但通常由两到四个神经元的小簇组成（65%）。此外，21个半球中有6个包含单个大得多（6 - 150个细胞）的放射状簇。尽管在28%的实验中观察到了大簇，但它们包含许多神经元，占逆转录病毒标记细胞的38%。通过组织学分析或PCR分析，大簇最多显示出很少广泛分散的同胞细胞，这表明放射状克隆和广泛分布的克隆共存，但在皮质发生的早期阶段在谱系上是分开的。大型放射状和广泛分布的神经元克隆共存似乎是皮质神经发生的一种进化保守机制。
