Is cerebellar granule cell migration regulated by an internal clock?
Is cerebellar granule cell migration regulated by an internal clock?
复制标题
小脑颗粒细胞迁移是否受内部时钟调节？
作者：
E. Trenkner;D. Smith;N. Segil
我们研究了微孔组织培养系统中小脑颗粒细胞迁移行为的时间过程。 [3H]胸苷作为特定颗粒细胞世代的标记。 [3H]胸苷注射后 4 小时，在微孔培养物中培养 6 天，观察到标记的颗粒细胞沿着纤维束迁移，在称为“电缆”的重新聚集体之间扩展 3 至 4 天。体外 5 天和 6 天后，在重新聚集体和电缆上发现的标记非迁移细胞的百分比显着增加。而未标记的细胞则继续迁移。当颗粒细胞在标记后在体内发育不同时间并在体外测定其发育状态时，获得了可比较的结果。培养前 1 至 4 天标记的小脑细胞群保持其体外迁移能力，即使在颗粒细胞进入内部颗粒细胞层后也是如此。相比之下，培养前5天和6天标记的迁移细胞的百分比显着降低。结果表明，颗粒细胞迁移的时间跨度是内在预先确定的，而不是由外部信号决定的。
We have studied the time course of migratory behavior of cerebellar granule cells in the microwell tissue culture system. [3H]Thymidine served as a marker for particular granule cell generations. When cultured 4 hr after [3H]thymidine injection for 6 days in microwell cultures, labeled granule cells were seen to migrate along fiber bundles expanding between reaggregates called “cables” for 3 to 4 days. After 5 and 6 days in vitro the percentage of labeled non-migrating cells found in clusters in reaggregates and on cables increased considerably. Whereas unlabeled cells continued to migrate. Comparable results were obtained when granule cells developed in vivo for various times after label and their developmental state was determined in vitro. Cells from cerebellar populations labeled 1 to 4 days before culture maintained their ability to migrate in vitro, even after granule cells had entered the internal granule cell layer. In contrast, the percentage of migrating cells labeled 5 and 6 days before culture was reduced significantly. The results suggest that the time span of granule cell migration is predetermined intrinsically rather than by external signals.