The bending of simple cellular sheets into complex three-dimensional (3D) forms requires developmental patterning cues to specify where deformations occur, but how positional information directs morphological change is poorly understood. Here, we investigate how morphogen signaling and cell fate diversification contribute to the morphogenesis of murine hair placodes, in which collective cell movements transform radially symmetric primordia into bilaterally symmetric tubes. Through live imaging and 3D volumetric reconstructions, we demonstrate that Wnt and Shh establish radial patterns of cell fate, cell morphology, and movement within developing placodes. Cell fate diversity at different radial positions provides unique and essential contributions to placode morphogenesis. Further, we show that downstream of radial patterning, gradients of classical cadherin expression are required for efficient epithelial rearrangements. Given that the transformation of epithelial discs into 3D tubes is a common morphological motif used to shape diverse organ primordia, mechanisms of radially patterned morphogenesis are likely highly conserved across evolution.

中文翻译：

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小鼠毛囊斑块的放射状形态发生确保了稳健的上皮出芽


将简单的细胞片弯曲成复杂的三维 （3D） 形式需要发育模式线索来指定变形发生的位置，但人们对位置信息如何指导形态变化知之甚少。在这里，我们研究了形态发生素信号传导和细胞命运多样化如何促进小鼠毛发板的形态发生，其中集体细胞运动将径向对称的原基转化为双侧对称的管。通过实时成像和 3D 体积重建，我们证明 Wnt 和 Shh 在发育中的板块内建立了细胞命运、细胞形态和运动的径向模式。不同放射状位置的细胞命运多样性为平板细胞形态发生提供了独特而重要的贡献。此外，我们表明，在径向模式的下游，经典钙粘蛋白表达的梯度是有效上皮重排所必需的。鉴于上皮盘转化为 3D 管是用于塑造不同器官原基的常见形态基序，径向图案形态发生机制在整个进化过程中可能高度保守。