Localization of Shh expression by Wnt and Eda affects axial polarity and shape of hairs
Localization of Shh expression by Wnt and Eda affects axial polarity and shape of hairs
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DOI：
10.1016/j.ydbio.2007.02.010
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发表时间：
2007-05-01
影响因子：
2.7
通讯作者：
Schlake, Thomas
中科院分区：
文献类型：
--
作者：
Hammerschmidt, Brigitte;Schlake, Thomas
轴向图案是胚胎发育过程中反复出现的主题。为了阐明其基本原理，毛囊由于其易于获取和可分配性而成为一个有吸引力的模型。毛囊的不对称性从其角度和相关结构的定位中可以明显看出。然而，轴向图案并不限于毛囊本身，还会产生旋转毛干不对称，对于锯齿形毛发，会产生 3-4 个弯曲，这些弯曲交替指向相反方向。在这里，我们通过分析突变和转基因小鼠表明，WNT 和外胚层蛋白信号传导分别参与控制毛囊和相关毛干的分子和形态不对称性。不对称性受到成熟毛囊中极化 WNT 和外胚层蛋白信号传导的影响。当内源性信号传导受损时，分子不对称性就会消失，小鼠就不再形成锯齿形毛发。两条信号通路都会影响 Shh 的极化表达，而 Shh 可能作为所有毛囊中毛干生成的定向参考。我们认为这种调节途径还在形态发生过程中建立了卵泡的不对称性。此外，所识别的分子层次结构为锯齿状毛发的周期性图案提供了一个模型，其机制类似于中胚层分割。 (c) 2007 Elsevier Inc. 保留所有权利。
Axial patterning is a recurrent theme during embryonic development. To elucidate its fundamental principles, the hair follicle is an attractive model due to its easy accessibility and dispensability. Hair follicle asymmetry is evident from its angling and the localization of associated structures. However, axial patterning is not restricted to the follicle itself but also generates rotational hair shaft asymmetry which, for zigzag hairs, generates 3-4 bends that alternately point into opposite directions. Here we show by analyzing mutant and transgenic mice that WNT and ectodysplasin signaling are involved in the control of the molecular and morphological asymmetry of the follicle and the associated hair shaft, respectively. Asymmetry is affected by polarized WNT and ectodysplasin signaling in mature hair follicles. When endogenous signaling is impaired, molecular asymmetry is lost and mice no longer form zigzag hairs. Both signaling pathways affect the polarized expression of Shh which likely functions as a directional reference for hair shaft production in all follicles. We propose that this regulatory pathway also establishes follicular asymmetry during morphogenesis. Moreover, the identified molecular hierarchy offers a model for the periodic patterning of zigzag hairs mechanistically similar to mesodermal segmentation. (c) 2007 Elsevier Inc. All rights reserved.