Compartmentalized Notch signaling sustains epithelial mirror symmetry
Compartmentalized Notch signaling sustains epithelial mirror symmetry
复制标题
DOI：
10.1242/dev.060566
复制
发表时间：
2011-03-15
期刊：
影响因子：
4.6
通讯作者：
Lopez-Schier, Hernan
中科院分区：
文献类型：
--
作者：
Wibowo, Indra;Pinto-Teixeira, Filipe;Lopez-Schier, Hernan
双侧对称组织必须解释轴向参考，以维持其在生长或修复过程中的整体结构。例如，斑马鱼侧线毛细胞的再生形成了一条垂直中线，将神经肥大上皮分成完美的镜像对称平面极化的两半。每一半都含有平面方向相同但与相对一半相反的毛细胞。在这一器官中建立双侧对称性的认识很少。在这里，我们表明，毛细胞再生是强烈的方向沿着轴垂直于上皮平面极性。我们证明了神经瘤中的隔室Notch信号传导，并表明定向再生取决于具有低Notch活性的极性隔室中毛细胞祖细胞的发育。高分辨率活细胞跟踪揭示了一种新的平面细胞倒置的过程，即兄弟毛细胞倒置后立即祖细胞胞质分裂的位置，表明定向祖细胞分裂是双侧对称的。尽管总是定向再生，上皮的平面极化最终对称地传播，因为成熟的毛细胞从中线向周围的神经肥大。我们的结论是，一个强烈的各向异性再生过程，依赖于动态稳定的祖身份在允许的极性隔间维持双边对称的侧线。
Bilateral symmetric tissues must interpret axial references to maintain their global architecture during growth or repair. The regeneration of hair cells in the zebrafish lateral line, for example, forms a vertical midline that bisects the neuromast epithelium into perfect mirror-symmetric plane-polarized halves. Each half contains hair cells of identical planar orientation but opposite to that of the confronting half. The establishment of bilateral symmetry in this organ is poorly understood. Here, we show that hair-cell regeneration is strongly directional along an axis perpendicular to that of epithelial planar polarity. We demonstrate compartmentalized Notch signaling in neuromasts, and show that directional regeneration depends on the development of hair-cell progenitors in polar compartments that have low Notch activity. High-resolution live cell tracking reveals a novel process of planar cell inversions whereby sibling hair cells invert positions immediately after progenitor cytokinesis, demonstrating that oriented progenitor divisions are dispensable for bilateral symmetry. Notwithstanding the invariably directional regeneration, the planar polarization of the epithelium eventually propagates symmetrically because mature hair cells move away from the midline towards the periphery of the neuromast. We conclude that a strongly anisotropic regeneration process that relies on the dynamic stabilization of progenitor identity in permissive polar compartments sustains bilateral symmetry in the lateral line.