Abstract
During embryonic development, mechanical forces are essential for cellular rearrangements driving tissue morphogenesis. Here, we show that in the early zebrafish embryo, friction forces are generated at the interface between anterior axial mesoderm (prechordal plate, ppl) progenitors migrating towards the animal pole and neurectoderm progenitors moving in the opposite direction towards the vegetal pole of the embryo. These friction forces lead to global rearrangement of cells within the neurectoderm and determine the position of the neural anlage. Using a combination of experiments and simulations, we show that this process depends on hydrodynamic coupling between neurectoderm and ppl as a result of E-cadherin-mediated adhesion between those tissues. Our data thus establish the emergence of friction forces at the interface between moving tissues as a critical force-generating process shaping the embryo.
Highlights
Throughout embryonic development, tissue morphogenesis depends on mechanical forces that drive cell rearrangements and global tissue shape changes[1,2]
To investigate the role of mesendoderm in neurectoderm morphogenesis, we turned to zebrafish maternal zygotic (MZ) one-eyed-pinhead mutant embryos 9, which lack much of the mesendoderm germ layers due to defective Nodal/TGFβ-signaling
Consistent with ppl and neurectoderm cells forming E-cadherin mediated cell-cell contacts, we found interstitial fluid (IF) accumulations to be absent from places where E-cadherin accumulates at the neurectoderm-ppl interface (Supplementary Fig. 1d)
Summary
Throughout embryonic development, tissue morphogenesis depends on mechanical forces that drive cell rearrangements and global tissue shape changes[1,2]. Internalization, convergence and extension constitute the main cellular processes by which the embryo takes shape[3]. Generating mechanisms mediating these different cellular processes[3], how forces between neighboring tissues are generated, perceived and integrated is yet poorly understood. The zebrafish nervous system organization becomes first apparent at gastrulation[5], and morphogenesis of the neurectoderm is accompanied by neighboring tissues undergoing dynamic cellular reorganization[6]. Recent studies in zebrafish suggested that the formation of the mesoderm and endoderm (mesendoderm) germ layers is required for proper morphogenesis of the overlying neurectoderm during neural keel formation[7,8]. The mechanisms by which mesendoderm influences neurectoderm morphogenesis have only started to be unraveled
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