Local and tissue-scale forces drive oriented junction growth during tissue extension
Local and tissue-scale forces drive oriented junction growth during tissue extension
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DOI：
10.1038/ncb3226
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发表时间：
2015-10-01
影响因子：
21.3
通讯作者：
Lecuit, Thomas
中科院分区：
文献类型：
--
作者：
Collinet, Claudio;Rauzi, Matteo;Lecuit, Thomas
聚合延伸是一个普遍的形态发生过程驱动的极化细胞嵌入。在果蝇生殖带中，上皮嵌入包括前-后相邻细胞之间的连接丧失，然后是背-腹相邻细胞之间的新连接生长。关于主动应力如何驱动极化结收缩，我们知道得很多。然而，目前还不清楚组织的收敛-延伸是如何从局部连接重塑中出现的，以及连接生长的具体作用是什么。在这里，我们报告说，组织收敛和扩展主要与新的连接生长。模拟和在体内的机械扰动表明，交界处的增长是由于局部极化应力驱动的内侧肌动球蛋白收缩。此外，我们发现，组织规模的拉力在边界处的内陷后中肠积极参与组织的延伸，定向交界处的增长。因此，组织延伸类似于极化流体流动，其需要平行且协调的局部和组织规模的力来驱动接合生长和细胞-细胞移位。
Convergence-extension is a widespread morphogenetic process driven by polarized cell intercalation. In the Drosophila germ band, epithelial intercalation comprises loss of junctions between anterior-posterior neighbours followed by growth of new junctions between dorsal-ventral neighbours. Much is known about how active stresses drive polarized junction shrinkage. However, it is unclear how tissue convergence-extension emerges from local junction remodelling and what the specific role, if any, of junction growth is. Here we report that tissue convergence and extension correlate mostly with new junction growth. Simulations and in vivo mechanical perturbations reveal that junction growth is due to local polarized stresses driven by medial actomyosin contractions. Moreover, we find that tissue-scale pulling forces at the boundary with the invaginating posterior midgut actively participate in tissue extension by orienting junction growth. Thus, tissue extension is akin to a polarized fluid flow that requires parallel and concerted local and tissue-scale forces to drive junction growth and cell-cell displacement.