Reintsch Wolfgang E, Habring-Mueller Anette, Wang Renee W, Schohl Anne, Fagotto François
McGill University, Department of Biology, Montreal, Quebec, Canada.
J Cell Biol. 2005 Aug 15;170(4):675-86. doi: 10.1083/jcb.200503009.
In Xenopus laevis, patterning of the trunk mesoderm into the dorsal notochord and lateral somites depends on differential regulation of Wnt-beta-catenin signaling. To study the cellular requirements for the physical separation of these tissues, we manipulated beta-catenin activity in individual cells that were scattered within the trunk mesoderm. We found that high activity led to efficient cell sorting from the notochord to the somites, whereas reduced activity led to sorting in the opposite direction. Analysis of individual cells overexpressing beta-catenin revealed that these cells were unable to establish stable contacts with notochord cells but could freely cross the boundary to integrate within the somitic tissue. Interference with cadherin-mediated adhesion disrupted tissue architecture, but it did not affect sorting and boundary formation. Based on these results, we propose that the boundary itself is the result of cell-autonomous changes in contact behavior that do not rely on differences in absolute levels of adhesion.
在非洲爪蟾中，躯干中胚层分化为背侧脊索和外侧体节依赖于Wnt-β-连环蛋白信号通路的差异调控。为了研究这些组织物理分离的细胞需求，我们在分散于躯干中胚层的单个细胞中操纵β-连环蛋白的活性。我们发现，高活性导致细胞从脊索有效分选到体节，而活性降低则导致相反方向的分选。对过表达β-连环蛋白的单个细胞的分析表明，这些细胞无法与脊索细胞建立稳定的接触，但可以自由穿过边界整合到体节组织中。干扰钙黏蛋白介导的黏附会破坏组织结构，但不影响分选和边界形成。基于这些结果我们提出，边界本身是接触行为中细胞自主变化的结果，并不依赖于绝对黏附水平的差异。
