Competence of cranial ectoderm to respond to Fgf signaling suggests a two-step model of otic placode induction
Competence of cranial ectoderm to respond to Fgf signaling suggests a two-step model of otic placode induction
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DOI：
10.1242/dev.02267
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发表时间：
2006-03-01
期刊：
影响因子：
4.6
通讯作者：
Groves, AK
中科院分区：
文献类型：
--
作者：
Martin, K;Groves, AK
脊椎动物的颅面感觉器官源自发育早期的外胚层基板。有人认为，所有颅面基板均源自与前神经板相邻的共同外胚层结构域，并且最近已鉴定出许多标记此类“前基板”结构域的基因。然而，这个前基板结构域的功能意义仍不清楚。在本研究中，我们表明 Fgf 信号传导对于直接诱导取自前基板结构域的外胚层中耳基板的一些（但不是全部）标记是必要且充分的。相比之下，来自该域之外的外胚层不能表达响应 Fgfs 的耳标记。将幼稚外胚层移植到前基板区域会在 8 小时内引起前基板标记物的上调，同时获得响应 Fgf 信号传导的能力。这表明颅面基板诱导的两步模型，其中外胚层首先获得前基板区域身份，然后在局部诱导信号的影响下分化成特定的颅面基板。
Vertebrate craniofacial sensory organs derive from ectodermal placodes early in development. it has been suggested that all craniofacial placodes arise from a common ectodermal domain adjacent to the anterior neural plate, and a number of genes have been recently identified that mark such a 'pre-placodal' domain. However, the functional significance of this pre-placodal domain is still unclear. In the present study, we show that Fgf signaling is necessary and sufficient to directly induce some, but not all, markers of the otic placode in ectoderm taken from the pre-placodal domain. By contrast, ectoderm from outside this domain is not competent to express otic markers in response to Fgfs. Grafting naive ectoderm into the pre-placodal domain causes upregulation of pre-placodal markers within 8 hours, together with the acquisition of competence to respond to Fgf signaling. This suggests a two-step model of craniofacial placode induction in which ectoderm first acquires pre-placodal region identity, and subsequently differentiates into particular craniofacial placodes under the influence of local inducing signals.