Expanding Actin Rings Zipper the Mouse Embryo for Blastocyst Formation Zenker, Jennifer et al. Cell, Volume 173, Issue 3, 776 - 791.e17
Abstract:
Transformation from morula to blastocyst is a defining event of preimplantation embryo development. During this transition, the embryo must establish a paracellular permeability barrier to enable expansion of the blastocyst cavity. Here, using live imaging of mouse embryos, we reveal an actin-zippering mechanism driving this embryo sealing. Preceding blastocyst stage, a cortical F-actin ring assembles at the apical pole of the embryo’s outer cells. The ring structure forms when cortical actin flows encounter a network of polar microtubules that exclude F-actin. Unlike stereotypical actin rings, the actin rings of the mouse embryo are not contractile, but instead, they expand to the cell-cell junctions. Here, they couple to the junctions by recruiting and stabilizing adherens and tight junction components. Coupling of the actin rings triggers localized myosin II accumulation, and it initiates a tension-dependent zippering mechanism along the junctions that is required to seal the embryo for blastocyst formation
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Funding Info:
This work was supported by funds from the DFG ( ZE997/1-1 ), SNF ( PBLAP3-145877 ), and HFSP ( LT000164/2015 ) to J.Z.; EMBL Australia to M.B.; and A∗STAR ( 2013APP005 ), EMBO , and HHMI-Wellcome Trust to N.P. H.Y.G.L. is a member of the Graduate School for Integrative Sciences and Engineering, NUS.
Description:
The full paper is available for download at the publisher's URL: https://doi.org/10.1016/j.cell.2018.02.035