Ben-Ze'ev A, Amsterdam A
Proc Natl Acad Sci U S A. 1986 May;83(9):2894-8. doi: 10.1073/pnas.83.9.2894.
The organization and the expression of cytoskeletal proteins involved in determining cell contact and shape were analyzed in granulosa cells during their differentiation on extracellular matrix (ECM)-coated culture plates. Rat granulosa cells from preovulatory follicles displayed an epithelial shape on ECM and formed multilayered aggregates with numerous gap junctions between neighboring cells. These cells had few actin cables and often only a diffuse pattern of actin and a low amount of vinculin in very thin focal adhesion sites. In contrast, cells grown on plastic formed a monolayer of flat cells with a reduced number of gap junctions but with numerous stress fibers and abundant large vinculin-containing focal contacts. On ECM, the cells were stimulated to produce high levels of progesterone, while only trace amounts of the steroid accumulated in cells on plastic dishes. Two-dimensional gel electrophoretic analysis of [35S]methionine-labeled cells revealed a dramatic decrease in vinculin, alpha-actinin, and actin synthesis in cells grown on ECM, as compared to cells grown on plastic, while the synthesis of the tubulins and of the intermediate filament protein vimentin remained unchanged. RNA blot analysis showed a marked decrease in actin mRNA levels in cells from ECM plates, while the level of tubulin mRNA remained essentially unchanged. It is concluded that the differentiation of granulosa cells on ECM in vitro is associated with changes in cell shape and cell contacts and that such changes in cell morphology are accompanied by simultaneous alterations in the organization and expression of cytoskeletal proteins that are involved in determining these cellular structures.
在包被细胞外基质（ECM）的培养板上，对颗粒细胞在分化过程中参与决定细胞接触和形状的细胞骨架蛋白的组织和表达进行了分析。来自排卵前卵泡的大鼠颗粒细胞在ECM上呈现上皮样形态，并形成多层聚集体，相邻细胞间有大量间隙连接。这些细胞几乎没有肌动蛋白束，通常只有弥散的肌动蛋白模式，并且在非常薄的黏着斑位点中有少量纽蛋白。相比之下，在塑料培养板上生长的细胞形成单层扁平细胞，间隙连接数量减少，但有大量应力纤维和丰富的含大量纽蛋白的黏着斑。在ECM上，细胞被刺激产生高水平的孕酮，而在塑料培养皿上生长的细胞中仅积累微量的这种类固醇。对[35S]甲硫氨酸标记的细胞进行二维凝胶电泳分析显示，与在塑料培养板上生长的细胞相比，在ECM上生长的细胞中纽蛋白、α-辅肌动蛋白和肌动蛋白的合成显著减少，而微管蛋白和中间丝蛋白波形蛋白的合成保持不变。RNA印迹分析表明，来自ECM培养板的细胞中肌动蛋白mRNA水平显著降低，而微管蛋白mRNA水平基本保持不变。结论是，体外颗粒细胞在ECM上的分化与细胞形状和细胞接触的变化有关，并且这种细胞形态的变化伴随着参与决定这些细胞结构的细胞骨架蛋白的组织和表达的同时改变。
