Steinberg M S, Takeichi M
Department of Molecular Biology, Princeton University, NJ 08544.
Proc Natl Acad Sci U S A. 1994 Jan 4;91(1):206-9. doi: 10.1073/pnas.91.1.206.
The sorting-out of embryonic cells from a cell mixture and the selective spreading of one cell population over the surface of another have been attributed to various causes. These include differentials in chemotaxis, in cellular adhesiveness, in cell surface contractility, in speed of cell movement, and in the timing of postulated changes in cellular adhesive and motile properties. One of us earlier predicted on mathematical grounds that two motile cell types differing only in the level of expression of a single cell adhesion system should not only segregate from one another but also arrange themselves with the less cohesive cells enveloping a core of the more cohesive ones. To test these predictions, we combined two populations of L cells transfected with P-cadherin cDNA and expressing this homophilic adhesion molecule in substantially differing amounts. When the two cell populations were intermixed, they segregated to approach a sphere-within-a-sphere configuration, the cell population expressing more P-cadherin forming islands which fused to become an internal "medulla." When the two cell populations were first formed into separate aggregates which were subsequently allowed to fuse, the cell population expressing more P-cadherin was enveloped by its partner, which formed an external "cortex." These observations confirm the early prediction and support the conclusion that both morphogenetic movements and the specific anatomical configurations to which they lead can be determined by particular sets of intercellular adhesive intensities, regardless of how these are generated and in the absence of differentials in other parameters.
从细胞混合物中分离胚胎细胞，以及一个细胞群体在另一个细胞群体表面的选择性铺展，被归因于多种原因。这些原因包括趋化性差异、细胞黏附性差异、细胞表面收缩性差异、细胞移动速度差异，以及假定的细胞黏附性和运动性属性变化的时间差异。我们中的一人早些时候基于数学原理预测，仅在单一细胞黏附系统表达水平上存在差异的两种运动细胞类型，不仅应该彼此分离，而且应该以黏附性较弱的细胞包裹黏附性较强的细胞核心的方式进行排列。为了验证这些预测，我们将两个转染了P-钙黏蛋白cDNA并大量表达这种同嗜性黏附分子的L细胞群体进行了混合。当这两个细胞群体混合时，它们分离并接近一种球中球的结构，表达更多P-钙黏蛋白的细胞群体形成岛屿，这些岛屿融合形成内部的“髓质”。当这两个细胞群体首先形成单独的聚集体，随后使其融合时，表达更多P-钙黏蛋白的细胞群体被其伙伴包裹，伙伴形成外部的“皮质”。这些观察结果证实了早期的预测，并支持这样的结论：形态发生运动及其导致的特定解剖结构都可以由特定的细胞间黏附强度组来决定，无论这些强度是如何产生的，也无论其他参数是否存在差异。
