The development of archosaurian first-generation teeth in a chicken mutant
The development of archosaurian first-generation teeth in a chicken mutant
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DOI：
10.1016/j.cub.2005.12.047
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发表时间：
2006-02-21
期刊：
影响因子：
9.2
通讯作者：
Fallon, JF
中科院分区：
文献类型：
--
作者：
Harris, MP;Hasso, SM;Fallon, JF
现代鸟类没有牙齿。相反，它们发展出一种特殊的角化结构，称为rhamphotheca，覆盖下颌骨，上颌骨和前颌骨。虽然重组研究表明，鸟类表皮可以响应来自小鼠或蜥蜴口腔间充质的牙齿诱导线索，并参与牙齿形成[1，2]，但在鸟类中重新启动牙齿发育的尝试失败了。在这里，我们描述了talpid（2）鸡突变体牙齿的形成，包括与牙齿形成相关的发育过程和早期分子变化。此外，我们还显示了在野生型胚胎中β-连环蛋白体内激活后，在talpid（2）中观察到的早期事件的重演。我们比较了talpid（2）突变体和短吻鳄牙齿的形成，并显示了在鸟类胚胎中明显的第一代牙齿的形成。突变体牙齿的形成与颌骨的口/背口边界的规格改变相结合。我们提出了一个表观遗传模型的发展修改的齿系在鸟类的进化，在这个模型中，在主管牙源性间充质的横向信号中心的相对位置的变化导致鸟类的牙齿损失，同时保持牙齿发育潜力。
Modern birds do not have teeth. Rather, they develop a specialized keratinized structure, called the rhamphotheca, that covers the mandible, maxillae, and premaxillae. Although recombination studies have shown that the avian epidermis can respond to tooth-inductive cues from mouse or lizard oral mesenchyme and participate in tooth formation [1, 2], attempts to initiate tooth development de novo in birds have failed. Here, we describe the formation of teeth in the talpid(2) chicken mutant, including the developmental processes and early molecular changes associated with the formation of teeth. Additionally, we show recapitulation of the early events seen in talpid(2) after in vivo activation of beta-catenin in wild-type embryos. We compare the formation of teeth in the talpid(2) mutant with that in the alligator and show the formation of decidedly archosaurian (crocodilian) first-generation teeth in an avian embryo. The formation of teeth in the mutant is coupled with alterations in the specification of the oral/aboral boundary of the jaw. We propose an epigenetic model of the developmental modification of dentition in avian evolution; in this model, changes in the relative position of a lateral signaling center over competent odontogenic mesenchyme led to loss of teeth in avians while maintaining tooth developmental potential.