Requirement for frzb and fzd7a in cranial neural crest convergence and extension mechanisms during zebrafish palate and jaw morphogenesis
Requirement for frzb and fzd7a in cranial neural crest convergence and extension mechanisms during zebrafish palate and jaw morphogenesis
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DOI：
10.1016/j.ydbio.2013.06.012
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发表时间：
2013-09-15
影响因子：
2.7
通讯作者：
Liao, Eric C.
中科院分区：
文献类型：
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作者：
Kamel, George;Hoyos, Tatiana;Liao, Eric C.
通过wnt-卷曲信号调节聚合和延伸是胚胎发生中的一个共同主题。本研究探讨frzb和fzd 7a在颅面发育过程中汇聚和伸展机制的功能需求。通过morpholino knockdown的方法，我们发现frzb和fzd 7a对于双侧骨小梁的定向迁移是必需的，但是对于腭部的会聚和伸展是必需的，其中伸展过程是由软骨细胞增殖、形态变化和嵌入介导的。与此相反，frzb和fzd 7a是下颌骨前伸的会聚所必需的，其中frzb或fzd 7a的敲除导致下颌结构的完全丧失。此外，我们发现bapx 1在wnt 9a/frzb/fzd 7a变体中特异性下调，而一般的神经嵴标记不受影响。另外，wnt 9a和frzb的表达在edn-/-突变体中也不存在。值得注意的是，bapx 1的过度表达足以部分挽救wnt 9a/frzb/fzd 7a变体中的下颌骨元件，证明bapx 1在下颌骨发育中作用于edn 1和wnt 9a/frzb/fzd 7a下游的遗传上位性。这项研究强调了wnt-卷曲信号在腭部和颅面形态发生中的会聚和伸展中的重要作用，上下颌结构的不同调节，以及wnt-卷曲信号与内皮素信号的整合以协调面部形状的形成。(C)2013 Elsevier Inc. All rights reserved.
Regulation of convergence and extension by wnt-frizzled signaling is a common theme in embryogenesis. This study examines the functional requirements of frzb and fzd7a in convergence and extension mechanisms during craniofacial development. Using a morpholino knockdown approach, we found that frzb and fzd7a are dispensable for directed migration of the bilateral trabeculae, but necessary for the convergence and extension of the palatal elements, where the extension process is mediated by chondrocyte proliferation, morphologic change and intercalation. In contrast, frzb and fzd7a are required for convergence of the mandibular prominences, where knockdown of either frzb or fzd7a resulted in complete loss of lower jaw structures. Further, we found that bapx1 was specifically downregulated in the wnt9a/frzb/fzd7a morphants, while general neural crest markers were unaffected. In addition, expression of wnt9a and frzb was also absent in the edn-/- mutant. Notably, over-expression of bapx1 was sufficient to partially rescue mandibular elements in the wnt9a/frzb/fzd7a morphants, demonstrating genetic epistasis of bapx1 acting downstream of edn1 and wnt9a/frzb/fzd7a in lower jaw development. This study underscores the important role of wnt-frizzled signaling in convergence and extension in palate and craniofacial morphogenesis, distinct regulation of upper vs. lower jaw structures, and integration of wnt-frizzled with endothelin signaling to coordinate shaping of the facial form. (C) 2013 Elsevier Inc. All rights reserved.