Kulesa P M, Fraser S E
Division of Biology, Beckman Institute 139-74, California Institute of Technology, Pasadena, CA, USA.
Development. 2000 Mar;127(6):1161-72. doi: 10.1242/dev.127.6.1161.
Hindbrain neural crest cells were labeled with DiI and followed in ovo using a new approach for long-term time-lapse confocal microscopy. In ovo imaging allowed us to visualize neural crest cell migration 2-3 times longer than in whole embryo explant cultures, providing a more complete picture of the dynamics of cell migration from emergence at the dorsal midline to entry into the branchial arches. There were aspects of the in ovo neural crest cell migration patterning which were new and different. Surprisingly, there was contact between neural crest cell migration streams bound for different branchial arches. This cell-cell contact occurred in the region lateral to the otic vesicle, where neural crest cells within the distinct streams diverted from their migration pathways into the branchial arches and instead migrated around the otic vesicle to establish a contact between streams. Some individual neural crest cells did appear to cross between the streams, but there was no widespread mixing. Analysis of individual cell trajectories showed that neural crest cells emerge from all rhombomeres (r) and sort into distinct exiting streams adjacent to the even-numbered rhombomeres. Neural crest cell migration behaviors resembled the wide diversity seen in whole embryo chick explants, including chain-like cell arrangements; however, average in ovo cell speeds are as much as 70% faster. To test to what extent neural crest cells from adjoining rhombomeres mix along migration routes and within the branchial arches, separate groups of premigratory neural crest cells were labeled with DiI or DiD. Results showed that r6 and r7 neural crest cells migrated to the same spatial location within the fourth branchial arch. The diversity of migration behaviors suggests that no single mechanism guides in ovo hindbrain neural crest cell migration into the branchial arches. The cell-cell contact between migration streams and the co-localization of neural crest cells from adjoining rhombomeres within a single branchial arch support the notion that the pattern of hindbrain neural crest cell migration emerges dynamically with cell-cell communication playing an important guidance role.
用碘化二苯（DiI）标记后脑神经嵴细胞，并采用一种新的长期延时共聚焦显微镜方法在鸡胚内进行追踪观察。鸡胚内成像使我们能够观察神经嵴细胞迁移的时间比在全胚胎外植体培养中长2至3倍，从而更完整地呈现细胞从背侧中线出现到进入鳃弓的迁移动态过程。鸡胚内神经嵴细胞迁移模式存在一些新的和不同的方面。令人惊讶的是，前往不同鳃弓的神经嵴细胞迁移流之间存在接触。这种细胞间接触发生在内耳囊外侧区域，在该区域，不同迁移流中的神经嵴细胞从它们进入鳃弓的迁移路径转向，而是围绕内耳囊迁移，从而在迁移流之间建立接触。一些单个神经嵴细胞似乎确实在迁移流之间穿过，但并没有广泛的混合。对单个细胞轨迹的分析表明，神经嵴细胞从所有菱脑节（r）出现，并分选到与偶数菱脑节相邻的不同输出迁移流中。神经嵴细胞的迁移行为类似于在全胚胎鸡外植体中看到的广泛多样性，包括链状细胞排列；然而，鸡胚内细胞的平均速度快达70%。为了测试相邻菱脑节的神经嵴细胞在迁移路径上以及在鳃弓内混合的程度，用DiI或DiD分别标记迁移前的神经嵴细胞群。结果表明，r6和r7神经嵴细胞迁移到第四鳃弓内的相同空间位置。迁移行为的多样性表明，没有单一机制引导鸡胚内后脑神经嵴细胞迁移到鳃弓中。迁移流之间的细胞间接触以及单个鳃弓内相邻菱脑节的神经嵴细胞的共定位支持了后脑神经嵴细胞迁移模式通过细胞间通讯发挥重要引导作用而动态形成的观点。
