Requirements for endoderm and BMP signaling in sensory neurogenesis in zebrafish
Requirements for endoderm and BMP signaling in sensory neurogenesis in zebrafish
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DOI：
10.1242/dev.01936
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发表时间：
2005-08-01
期刊：
影响因子：
4.6
通讯作者：
Schillili, TF
中科院分区：
文献类型：
--
作者：
Holzschuh, J;Wada, N;Schillili, TF
颅感觉神经元主要来源于神经原性基板（鳃上基板和背外侧基板），它们是外胚层增厚形成的与颅神经相关的感觉神经节，但基板发育的分子机制尚不清楚。在此，我们表明咽内胚层在斑马鱼中诱导鳃上神经发生，并且BMP信号传导在这一过程中起关键作用。利用her5:egfp转基因品系追踪活体胚胎中的内胚层运动，我们发现咽囊与表面外胚层之间的接触与鳃上基板神经发生的起始时间一致。通过基因消融以及通过细胞移植重新引入内胚层，我们表明这些接触促进神经发生。利用基因干扰方法，我们进一步确定bmp2b和bmp5是诱导鳃上神经发生的内胚层信号的关键成分。背外侧基板（三叉神经、听觉、前庭、侧线）独立于内胚层和BMP信号传导而发育，这表明这两组基板受不同的基因控制。我们的研究结果表明，内胚层调节颅感觉神经节的分化，从而使颅神经与其所支配的节段相协调。
Cranial sensory neurons largely derive from neurogenic placodes (epibranchial and dorsolateral), which are ectodermal thickenings that form the sensory ganglia associated with cranial nerves, but the molecular mechanisms of placodal development are unclear. Here, we show that the pharyngeal endoderm induces epibranchial neurogenesis in zebrafish, and that BMP signaling plays a crucial role in this process. Using a her5:egfp transgenic line to follow endodermal movements in living embryos, we show that contact between pharyngeal pouches and the surface ectoderm coincides with the onset of neurogenesis in epibranchial placodes. By genetic ablation and reintroduction of endoderm by cell transplantation, we show that these contacts promote neurogenesis. Using a genetic interference approach we further identify bmp2b and bmp5 as crucial components of the endodermal signals that induce epibranchial neurogenesis. Dorsolateral placodes (trigeminal, auditory, vestibular, lateral line) develop independently of the endoderm and BMP signaling, suggesting that these two sets of placodes; are under separate genetic control. Our results show that the endoderm regulates the differentiation of cranial sensory ganglia, which coordinates the cranial nerves with the segments that they innervate.