Krull C E, Collazo A, Fraser S E, Bronner-Fraser M
Developmental Biology Center, UC Irvine 92717, USA.
Development. 1995 Nov;121(11):3733-43. doi: 10.1242/dev.121.11.3733.
Trunk neural crest cells migrate through the somites in a striking segmental fashion, entering the rostral but not caudal sclerotome, via cues intrinsic to the somites. Attempts to define the molecular bases of these cues have been hampered by the lack of an accessible assay system. To examine trunk neural crest migration over time and to perturb candidate guiding molecules, we have developed a novel explant preparation. Here, we demonstrate that trunk regions of the chicken embryo, placed in explant culture, continue to develop apparently normally for 2 days. Neural crest cells, recognized by prelabeling with DiI or by poststaining with the HNK-1 antibody, migrate in the somites of the explants in their typical segmental pattern. Furthermore, this paradigm allows us to follow trunk neural crest migration in situ for the first time using low-light-level videomicroscopy. The trajectories of individual neural crest cells were often complex, with cells migrating in an episodic mode encompassing forward, backward and lateral movements. Frequently, neural crest cells migrated in close-knit groups of 2-4 cells, moving at mean rates of migration of 10-14 microns/hour. Treatment of the explants with the lectin peanut agglutinin (PNA) both slowed the rate and altered the pattern of neural crest migration. Neural crest cells entered both the rostral and caudal halves of the sclerotome with mean rates of migration ranging from 6 to 13 microns/hour. These results suggest that peanut agglutinin-binding molecules are required for the segmental patterning of trunk neural crest migration. Because this approach permits neural crest migration to be both observed and perturbed, it offers the promise of more direct assays of the factors that influence neural crest development.
躯干神经嵴细胞以一种显著的节段性方式穿过体节，通过体节固有的线索进入头侧而非尾侧的生骨节。由于缺乏可利用的检测系统，确定这些线索的分子基础的尝试受到了阻碍。为了研究躯干神经嵴随时间的迁移情况并干扰候选导向分子，我们开发了一种新型的外植体制备方法。在此，我们证明，置于外植体培养中的鸡胚躯干区域在2天内仍能明显正常发育。通过用DiI预标记或用HNK-1抗体进行后染色识别的神经嵴细胞，以其典型的节段性模式在外植体的体节中迁移。此外，这种模式首次使我们能够使用微光视频显微镜在原位追踪躯干神经嵴的迁移。单个神经嵴细胞的轨迹通常很复杂，细胞以包括向前、向后和侧向运动的间歇性模式迁移。神经嵴细胞经常以2 - 4个细胞紧密相连的群体形式迁移，平均迁移速度为10 - 14微米/小时。用凝集素花生凝集素（PNA）处理外植体，既减慢了迁移速度，又改变了神经嵴迁移的模式。神经嵴细胞以6至13微米/小时的平均迁移速度进入生骨节的头侧和尾侧两半。这些结果表明，花生凝集素结合分子是躯干神经嵴迁移节段性模式所必需的。因为这种方法能够观察和干扰神经嵴的迁移，所以它有望更直接地检测影响神经嵴发育的因素。
