Department of Medical Neurobiology, IMRIC, Hebrew University-Hadassah Medical School, Jerusalem, Israel.
Development. 2010 Feb;137(4):585-95. doi: 10.1242/dev.041509.
Colonization of trunk neural crest derivatives in avians follows a ventral to dorsal order beginning with sympathetic ganglia, Schwann cells, sensory ganglia and finally melanocytes. Continuous crest emigration underlies this process, which is accounted for by a progressive ventral to dorsal relocation of neural tube progenitors prior to departure. This causes a gradual narrowing of FoxD3, Sox9 and Snail2 expression domains in the dorsal tube that characterize the neural progenitors of the crest and these genes are no longer transcribed by the time melanoblasts begin emigrating. Consistently, the final localization of crest cells can be predicted from their relative ventrodorsal position within the premigratory domain or by their time of delamination. Thus, a dynamic spatiotemporal fate map of crest derivatives exists in the dorsal tube at flank levels of the axis with its midline region acting as a sink for the ordered ingression and departure of progenitors. Furthermore, discrete lineage analysis of the dorsal midline at progressive stages generated progeny in single rather than multiple derivatives, revealing early fate restrictions. Compatible with this notion, when early emigrating ;neural' progenitors were diverted into the lateral ;melanocytic' pathway, they still adopted neural traits, suggesting that initial fate acquisition is independent of the migratory environment and that the potential of crest cells prior to emigration is limited.
鸟类主干神经嵴衍生物的殖民化遵循从腹侧向背侧的顺序，首先是交感神经节、许旺细胞、感觉神经节，最后是黑色素细胞。这种连续的嵴迁出是由神经管祖细胞在离开前逐渐从腹侧向背侧重新定位引起的。这导致 FoxD3、Sox9 和 Snail2 表达区域在背侧管中逐渐变窄，这些区域特征是嵴的神经祖细胞，并且这些基因在黑色素细胞开始迁出时不再转录。一致地，嵴细胞的最终定位可以根据其在迁移前区域内的相对腹侧-背侧位置或其分层时间来预测。因此，在轴的侧翼水平的背侧管中存在嵴衍生物的动态时空命运图谱，其中线区域充当祖细胞有序入侵和离开的汇点。此外，在渐进阶段对背中线的离散谱系分析产生了单一而非多个衍生物中的后代，揭示了早期命运限制。与这一观点一致的是，当早期迁移的“神经”祖细胞被转移到外侧“黑色素细胞”途径时，它们仍然采用神经特征，表明初始命运获得独立于迁移环境，并且迁移前嵴细胞的潜力是有限的。
