University of Toronto, Department of Cell and Systems Biology, Toronto, M5S 3G5 Canada.
J Cell Sci. 2012 Apr 15;125(Pt 8):1877-83. doi: 10.1242/jcs.095315. Epub 2012 Feb 10.
Adhesion differences between cell populations are in principle a source of strong morphogenetic forces promoting cell sorting, boundary formation and tissue positioning, and cadherins are main mediators of cell adhesion. However, a direct link between cadherin expression, differential adhesion and morphogenesis has not yet been determined for a specific process in vivo. To identify such a connection, we modulated the expression of C-cadherin in the Xenopus laevis gastrula, and combined this with direct measurements of cell adhesion-related parameters. Our results show that gastrulation is surprisingly tolerant of overall changes in adhesion. Also, as expected, experimentally generated, cadherin-based adhesion differences promote cell sorting in vitro. Importantly, however, such differences do not lead to the sorting of cells in the embryo, showing that differential adhesion is not sufficient to drive morphogenesis in this system. Compensatory recruitment of cadherin protein to contacts between cadherin-deprived and -overexpressing cells could contribute to the prevention of sorting in vivo.
细胞群体之间的黏附差异原则上是一种强大的形态发生力的来源，可促进细胞分选、边界形成和组织定位，而钙黏蛋白是细胞黏附的主要介质。然而，在体内特定过程中，尚未确定钙黏蛋白表达、差异黏附和形态发生之间的直接联系。为了确定这种联系，我们在非洲爪蟾原肠胚中调节 C-钙黏蛋白的表达，并将其与细胞黏附相关参数的直接测量相结合。我们的结果表明，原肠胚形成对整体黏附变化具有惊人的耐受性。此外，如预期的那样，实验产生的基于钙黏蛋白的黏附差异促进了体外细胞分选。然而，重要的是，这种差异不会导致胚胎中的细胞分选，表明在该系统中，差异黏附不足以驱动形态发生。钙黏蛋白蛋白在钙黏蛋白缺乏和过表达细胞之间的接触处的代偿性募集可能有助于防止体内分选。
