Université de Paris, Institut Jacques Monod, CNRS UMR 7592, Paris 75013, France.
Institut Pasteur, Paris 75015, France.
Dev Cell. 2019 Nov 18;51(4):516-525.e5. doi: 10.1016/j.devcel.2019.10.021.
Most animals exhibit mirror-symmetric body plans, yet the molecular constituents from which they are formed are often chiral. In planarian flatworms, centrioles are arranged in a bilaterally symmetric pattern across the ventral epidermis. Here, we found that this pattern is generated by a network of centrioles with prominent chiral asymmetric properties. We identify centriole components required for establishing asymmetric connections between centrioles and balancing their effects to align centrioles along polarity fields. SMED-ODF2, SMED-VFL1, and SMED-VFL3 affect the assembly of centriole appendages that tether cytoskeletal connectors to position the centrioles. We further show that the medio-lateral polarization of centrioles relies on mechanisms that are partly distinct on the left and right sides of the planarian body. Our findings shed light on how bilaterally symmetrical patterns can emerge from chiral cellular organizations.
大多数动物表现出镜像对称的身体结构，但构成它们的分子成分通常是手性的。在扁形动物涡虫中，中心粒沿腹表皮呈双侧对称排列。在这里，我们发现这种模式是由一个具有明显手性不对称特性的中心粒网络产生的。我们确定了中心粒组件，这些组件对于在中心粒之间建立不对称连接以及平衡它们的作用以沿着极性场对齐中心粒是必需的。SMED-ODF2、SMED-VFL1 和 SMED-VFL3 影响中心粒附属物的组装，这些附属物将细胞骨架连接器固定到中心粒的位置。我们进一步表明，中心粒的中侧极化依赖于在扁形动物身体的左右两侧部分不同的机制。我们的研究结果揭示了双侧对称模式如何从手性细胞组织中出现。
