Ben-Ze'ev A, Kohen F, Amsterdam A
Department of Genetics, Weizmann Institute of Science, Rehovot, Israel.
Differentiation. 1987;34(3):222-35. doi: 10.1111/j.1432-0436.1987.tb00070.x.
The gonadotropin-induced differentiation of granulosa cells in culture was studied, with particular attention being given to the organization and expression of cytoskeletal proteins involved in the formation of cell contacts, as well as to progesterone production. Gonadotropin-treated granulosa cells formed clusters of spherical cells containing few vinculin-containing focal contacts, exhibited a diffuse distribution of actin, and had few adherens junctions but more gap junctions than cells grown without the hormone. In gonadotropin-treated cells, the levels of synthesis of the cytoskeletal proteins, vinculin, alpha-actinin, and actin, were dramatically reduced, but the synthesis of the tubulins and vimentin was unaffected. Decreased levels of synthesis of these cytoskeletal proteins were also observed in an in vitro translation assay using poly(A)+ RNA from gonadotropin-treated cells. The hybridization of cytoplasmic RNA with cloned actin and vimentin cDNAs revealed a marked decrease in actin-RNA levels, but no change in vimentin-RNA levels in these cells. Such alterations in cytoskeletal-protein expression were also observed in cells treated with compounds that cause elevated cellular cAMP levels by acting at a stage beyond gonadotropin receptor stimulation. Furthermore, by keeping the cells in a spherical configuration in suspension culture, or by treating the cells with cytochalasin B, similar changes in the synthesis of these cytoskeletal proteins were observed. During this process, there was a concomitant increased in the production of progesterone (although to a much lesser extent in suspension culture) that occurred in parallel with the appearance of large mitochondria with lamellar-tubular cristae and a well-developed smooth endoplasmic reticulum, these features being characteristic of granulosa-lutein cells in vivo. Our results suggest that changes in cell shape and contact, together with the regulation of cytoskeletal elements that determine cellular morphogenesis, are part of the gonadotropin-controlled differentiation program in granulosa cells and may also occur during the maturation of these cells in vivo.
研究了促性腺激素诱导培养的颗粒细胞分化，特别关注参与细胞接触形成的细胞骨架蛋白的组织和表达，以及孕酮的产生。经促性腺激素处理的颗粒细胞形成了球形细胞簇，含有少量含纽蛋白的粘着斑，肌动蛋白呈弥散分布，粘着连接较少，但与未用该激素培养的细胞相比，间隙连接较多。在经促性腺激素处理的细胞中，细胞骨架蛋白纽蛋白、α - 辅肌动蛋白和肌动蛋白的合成水平显著降低，但微管蛋白和波形蛋白的合成未受影响。在使用来自经促性腺激素处理细胞的聚腺苷酸加尾RNA的体外翻译试验中，也观察到这些细胞骨架蛋白合成水平的降低。细胞质RNA与克隆的肌动蛋白和波形蛋白cDNA杂交显示，这些细胞中肌动蛋白RNA水平显著下降，但波形蛋白RNA水平没有变化。在用通过作用于促性腺激素受体刺激之后的阶段而导致细胞内cAMP水平升高的化合物处理的细胞中，也观察到细胞骨架蛋白表达的这种改变。此外，通过在悬浮培养中使细胞保持球形形态，或用细胞松弛素B处理细胞，观察到这些细胞骨架蛋白合成有类似变化。在此过程中，孕酮的产生同时增加（尽管在悬浮培养中程度要小得多），这与出现具有板层 - 管状嵴的大线粒体和发育良好的滑面内质网同时发生，这些特征是体内颗粒黄体细胞的特征。我们的结果表明，细胞形状和接触的变化，以及决定细胞形态发生的细胞骨架成分的调节，是促性腺激素控制的颗粒细胞分化程序的一部分，也可能发生在这些细胞在体内成熟的过程中。
