Is apparent autoregulatory control of tubulin synthesis nontranscriptionally regulated?
Is apparent autoregulatory control of tubulin synthesis nontranscriptionally regulated?
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DOI：
10.1083/jcb.97.3.919
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发表时间：
1983-09
期刊：
影响因子：
--
通讯作者：
Havercroft JC
中科院分区：
文献类型：
--
作者：
Cleveland DW;Havercroft JC
事实上，所有高等真核细胞都会响应增加解聚亚基池的微管抑制剂而迅速抑制新的α-和β-微管蛋白多肽的合成。这种微管蛋白合成的明显自动调节控制是通过调节微管蛋白信使 RNA 水平来实现的。特别是，在用微管解聚药物秋水仙碱处理的细胞中，微管蛋白信使RNA特异性且快速地从细胞质中丢失。推测这种损失可能是由于新的微管蛋白RNA转录受到抑制、新合成的微管蛋白RNA不能被正确加工或从细胞核转运、或者细胞质微管蛋白RNA降解速率增加的结果。尽管迄今为止详细研究的大多数细胞真核基因的转录调控已被证明，但我们发现，在秋水仙碱处理或对照细胞的分离核中，微管蛋白RNA转录的表观速率基本上没有变化。这一发现表明，响应亚基池改变而对微管蛋白基因表达的主要控制可能不是通过转录调节机制实现的。
Virtually all higher eucaryotic cells rapidly depress synthesis of new alpha- and beta-tubulin polypeptides in response to microtubule inhibitors that increase the pool of depolymerized subunits. This apparently autoregulatory control of tubulin synthesis is achieved through modulation of tubulin messenger RNA levels. In particular, in cells treated with the microtubule-depolymerizing drug colchicine, tubulin messenger RNAs are specifically and rapidly lost from the cell cytoplasm. A priori this loss may be the result of suppression of new tubulin RNA transcription, failure of newly synthesized tubulin RNAs to be properly processed or transported from the nucleus, or an increased rate of cytoplasmic tubulin RNA degradation. Although transcriptional regulation has been demonstrated for most cellular eucaryotic genes thus far investigated in detail, we found that the apparent rates of tubulin RNA transcription were essentially unchanged in isolated nuclei derived from colchicine treated or control cells. This finding argues that the principal control of tubulin gene expression in response to altered subunit pools is probably not achieved through a transcriptionally regulated mechanism.