Developmental Biology Program, Sloan-Kettering Institute, 1275 York Avenue, New York, NY 10065, USA.
Dev Cell. 2010 Sep 14;19(3):402-12. doi: 10.1016/j.devcel.2010.08.014.
Left-right (LR) patterning is an intriguing but poorly understood process of bilaterian embryogenesis. We report a mechanism for LR patterning in C. elegans in which the embryo uncouples its midline from the anteroposterior (AP) axis. Specifically, the eight-cell embryo establishes a midline that is tilted rightward from the AP axis and positions more cells on the left, allowing subsequent differential LR fate inductions. To establish the tilted midline, cells exhibit LR asymmetric protrusions and a handed collective movement. This process, termed chiral morphogenesis, involves differential regulation of cortical contractility between a pair of sister cells that are bilateral counterparts fate-wise and is activated by noncanonical Wnt signaling. Chiral morphogenesis is timed by the cytokinetic furrow of a neighbor of the sister pair, providing a developmental clock and an unexpected signaling interaction between the contractile ring and the adjacent cells.
左右（LR）模式是一种有趣但尚未被充分理解的两侧胚胎发生过程。我们报告了线虫中 LR 模式形成的一种机制，其中胚胎将中线与其前后（AP）轴解耦。具体来说，八细胞胚胎建立了一条从中线向右倾斜的中线，并使更多的细胞位于左侧，从而允许随后进行不同的 LR 命运诱导。为了建立倾斜的中线，细胞表现出 LR 不对称的突起和手性集体运动。这个过程被称为手性形态发生，涉及到一对姐妹细胞之间皮质收缩性的差异调节，这对姐妹细胞在命运上是双侧对应的，并且被非典型 Wnt 信号激活。手性形态发生由姐妹对的邻居的胞质分裂沟定时，提供了一个发育时钟和收缩环与相邻细胞之间的意外信号相互作用。
