Regulation of actin mRNA levels and translation responds to changes in cell configuration
Regulation of actin mRNA levels and translation responds to changes in cell configuration
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DOI：
10.1128/mcb.3.2.182-189.1983
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发表时间：
1983-02
影响因子：
5.3
通讯作者：
S. Farmer;K. Wan;A. Ben-Ze'ev;S. Penman
中科院分区：
文献类型：
--
作者：
S. Farmer;K. Wan;A. Ben-Ze'ev;S. Penman
已经研究了细胞构型在调节细胞代谢中的作用，使用其中细胞形状和表面接触可以容易地操纵的系统。在Methocel中的锚定依赖性小鼠成纤维细胞的悬浮液导致DNA、RNA和蛋白质合成的协调减少。这些过程在细胞重新附着到固体表面时恢复。这种恢复过程有两个或两个以上的组成部分：蛋白质合成的快速恢复只需要表面接触，和核事件的缓慢恢复，这取决于广泛的细胞扩散（A。Ben-Ze'ev，S.R. Farmer和S. Penman，Cell 21：365-372，1980）。在本研究中，我们研究了3 T3细胞，而在悬浮培养和附着到组织培养皿表面后，研究细胞构型依赖的特定细胞骨架蛋白基因的表达。与先前研究的3 T6细胞相比，这里使用的3 T3系成纤维细胞显示出更显著的这些反应。我们证明，而总蛋白质合成被强烈抑制后，悬浮，肌动蛋白的合成被优先抑制，从12%的总蛋白质合成在控制细胞中的悬浮细胞中的6%。这显然发生在肌动蛋白mRNA的翻译水平上，因为细胞质中肌动蛋白mRNA序列的量没有变化。再附着开始迅速恢复总蛋白质合成，这是伴随着一个戏剧性的，优先增加肌动蛋白的合成达到峰值的20 - 25%的总蛋白质合成4至6小时后，但随后下降到控制值的24小时。在体外翻译和杂交的mRNA克隆的肌动蛋白cDNA探针显示，肌动蛋白合成的诱导是由于在细胞质中的可翻译的mRNA序列的水平增加。这些结果暗示了细胞结构、特定细胞骨架蛋白基因的表达和生长控制之间的密切关系。肌动蛋白基因的表达似乎在翻译水平（悬浮期间）和mRNA产生水平（恢复期间）受到调节。
The role of cell configuration in regulating cell metabolism has been studied, using a system in which cell shape and surface contact can easily be manipulated. The suspension of anchorage-dependent mouse fibroblasts in Methocel results in a coordinate decrease of DNA, RNA, and protein synthesis. These processes are restored upon reattachment of cells to a solid surface. This recovery process has two or more components: a rapid recovery of protein synthesis requiring only surface contact, and a slower restoration of nuclear events which is dependent upon extensive cell spreading (A. Ben-Ze'ev, S.R. Farmer, and S. Penman, Cell 21:365-372, 1980). In the present study, we examined 3T3 cells while in suspension culture and after attachment to a tissue culture dish surface to study cell configuration-dependent expression of specific cytoskeleton protein genes. The 3T3 line of fibroblasts used here shows these responses much more dramatically compared with 3T6 cells previously studied. We demonstrate that whereas total protein synthesis was strongly inhibited upon suspension, actin synthesis was preferentially inhibited, decreasing from 12% of total protein synthesis in control cells to 6% in suspended cells. This occurred apparently at the level of translation of actin mRNA, since the amount of actin mRNA sequences in the cytoplasm was unchanged. Reattachment initiated the rapid recovery of overall protein synthesis which was accompanied by a dramatic, preferential increase in actin synthesis reaching peak values of 20 to 25% of total protein synthesis 4 to 6 h later, but then declining to control values by 24 h. Translation in vitro and hybridization of mRNA to a cloned actin cDNA probe revealed that the induction of actin synthesis was due to increased levels of translatable mRNA sequences in the cytoplasm. These results imply a close relationship among cell cytoarchitecture, expression of a specific cytoskeletal protein gene, and growth control. The expression of the actin gene appears to be regulated at both the level of translation (during suspension) and mRNA production (during recovery).