Geometric control of myosin II orientation during axis elongation.
Geometric control of myosin II orientation during axis elongation.
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DOI：
10.7554/elife.78787
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发表时间：
2023-01-30
期刊：
影响因子：
7.7
通讯作者：
Streichan SJ
中科院分区：
文献类型：
--
作者：
Lefebvre MF;Claussen NH;Mitchell NP;Gustafson HJ;Streichan SJ
肌动球蛋白细胞骨架是形态发生的关键驱动力。然而，在变形组织中，大尺度细胞骨架模式的行为是如何从几何学、遗传学和力学的相互作用中出现的，仍然没有完全弄清楚。在果蝇胚胎的收敛延伸提供了机会，以建立一个定量的了解各向异性非肌肉肌球蛋白II的动态。对固定胚胎中蛋白质定位的细胞规模分析表明，基因表达模式通过复杂的规则控制肌球蛋白各向异性。然而，技术上的限制阻碍了在整个胚胎水平上对这一过程进行定量和动态研究，使几何学的作用成为可能。在这里，我们结合联合收割机完全活的成像与分子动力学的定量分析来表征肌球蛋白各向异性的分布和相应的遗传模式。我们发现配对规则基因表达连续变形，随组织框架流动。与此相反，肌球蛋白各向异性方向保持近似静态，只有微弱的偏转从静止的背腹轴的胚胎。我们建议，肌球蛋白是由一个几何定义的静态源，可能与胚胎规模的上皮张力，并占瞬时偏转细胞骨架周转和交界处的流动重新定位。只有一个参数，该模型定量占肌球蛋白各向异性取向在野生型，扭曲，甚至跳过胚胎，以及胚胎与扰动鸡蛋的几何形状的时间过程。细胞骨架的几何图案表明了一种简单的物理策略，以确保强大的流动和形状的形成。
The actomyosin cytoskeleton is a crucial driver of morphogenesis. Yet how the behavior of large-scale cytoskeletal patterns in deforming tissues emerges from the interplay of geometry, genetics, and mechanics remains incompletely understood. Convergent extension in Drosophila melanogaster embryos provides the opportunity to establish a quantitative understanding of the dynamics of anisotropic non-muscle myosin II. Cell-scale analysis of protein localization in fixed embryos suggests that gene expression patterns govern myosin anisotropy via complex rules. However, technical limitations have impeded quantitative and dynamic studies of this process at the whole embryo level, leaving the role of geometry open. Here, we combine in toto live imaging with quantitative analysis of molecular dynamics to characterize the distribution of myosin anisotropy and the corresponding genetic patterning. We found pair rule gene expression continuously deformed, flowing with the tissue frame. In contrast, myosin anisotropy orientation remained approximately static and was only weakly deflected from the stationary dorsal-ventral axis of the embryo. We propose that myosin is recruited by a geometrically defined static source, potentially related to the embryo-scale epithelial tension, and account for transient deflections by cytoskeletal turnover and junction reorientation by flow. With only one parameter, this model quantitatively accounts for the time course of myosin anisotropy orientation in wild-type, twist, and even-skipped embryos, as well as embryos with perturbed egg geometry. Geometric patterning of the cytoskeleton suggests a simple physical strategy to ensure a robust flow and formation of shape.