Guo Chuanyu, Zou Jian, Wen Yi, Fang Wei, Stolz Donna Beer, Sun Ming, Wei Xiangyun
Department of Ophthalmology, University of Pittsburgh, 3501 Fifth Avenue, Pittsburgh, PA 15213, USA.
Department of Cell and Physiology, University of Pittsburgh, 3501 Fifth Avenue, Pittsburgh, PA 15213, USA.
iScience. 2018 May 25;3:63-85. doi: 10.1016/j.isci.2018.04.007.
The symmetric tissue and body plans of animals are paradoxically constructed with asymmetric cells. To understand how the yin-yang duality of symmetry and asymmetry are reconciled, we asked whether apical polarity proteins orchestrate the development of the mirror-symmetric zebrafish neural tube by hierarchically modulating apical cell-cell adhesions. We found that apical polarity proteins localize by a pioneer-intermediate-terminal order. Pioneer proteins establish the mirror symmetry of the neural rod by initiating two distinct types of apical adhesions: the parallel apical adhesions (PAAs) cohere cells of parallel orientation and the novel opposing apical adhesions (OAAs) cohere cells of opposing orientation. Subsequently, the intermediate proteins selectively augment the PAAs when the OAAs dissolve by endocytosis. Finally, terminal proteins are required to inflate the neural tube by generating osmotic pressure. Our findings suggest a general mechanism to construct mirror-symmetric tissues: tissue symmetry can be established by organizing asymmetric cells opposingly via adhesions.
动物对称的组织和身体结构却是由不对称细胞构建而成，这似乎自相矛盾。为了理解对称性和不对称性的阴阳二元性是如何协调的，我们探究了顶端极性蛋白是否通过分层调节顶端细胞间黏附来协调镜像对称的斑马鱼神经管的发育。我们发现顶端极性蛋白按先驱 - 中间 - 终端的顺序定位。先驱蛋白通过启动两种不同类型的顶端黏附来建立神经杆的镜像对称：平行顶端黏附（PAA）使平行排列的细胞黏合在一起，而新型反向顶端黏附（OAA）使反向排列的细胞黏合在一起。随后，当OAA通过内吞作用溶解时，中间蛋白选择性地增强PAA。最后，终端蛋白通过产生渗透压使神经管膨胀。我们的研究结果提示了一种构建镜像对称组织的通用机制：组织对称性可以通过黏附将不对称细胞反向组织起来而建立。
