An inhibitor of nuclear export activates the p53 response and induces the localization of HDM2 and p53 to U1A-positive nuclear bodies associated with the PODs
An inhibitor of nuclear export activates the p53 response and induces the localization of HDM2 and p53 to U1A-positive nuclear bodies associated with the PODs
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DOI：
10.1006/excr.1999.4433
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发表时间：
1999-05-01
影响因子：
3.7
通讯作者：
Lane, DP
中科院分区：
文献类型：
--
作者：
Laín, S;Midgley, C;Lane, DP
Leptomycin B 是一种细胞毒素，可直接与 CRM1 相互作用并抑制其作用，CRM1 是含有 HIV1 REV 型核输出信号 (NES) 的蛋白质核出口的重要介质。我们发现，向人原代成纤维细胞中添加瘦霉素 B 会增加 p53 肿瘤抑制蛋白的水平。这伴随着培养细胞中 p53 依赖性转录活性的诱导以及两个 p53 响应基因 p21(CIP1/WAF1) 和 HDM2 蛋白的产物水平的增加。轻霉素 B 诱导 p53 和 HDM2 在细胞核中积累，并出现含有这两种蛋白质的离散核聚集体。据报道，p53 的转录活性是通过其与 HDM2 蛋白的相互作用来调节的，而 HDM2 蛋白也以 p53 为目标进行快速降解。使用模型细胞。细胞系条件性表达 MDM2（HDM2 的鼠类类似物），我们提供的证据表明，leptomycin B 消除了 MDM2 在 p53 降解中的作用，并且 p53 在不同核体中的积累是由 MDM2 介导的。由于最近已证明 HDM2 含有 REV 类型的功能性 NES，因此对我们的结果最可能的解释是，瘦霉素 B 对 HDM2 和 p53 的影响是由于核输出的抑制。可视化 p53 和 HDM2 共定位位点的能力为研究体内两种蛋白质之间的关联提供了一种新方法。发现这些 p53/HDM2 阳性核灶还含有 U1A snRNP A 并与 PML 致癌结构域并置。 (C) 1999 年学术出版社。
Leptomycin B is a cytotoxin which directly interacts with and inhibits the action of CRM1, an essential mediator of the nuclear exit of proteins containing nuclear export signals (NES) of the HIV1 REV type. We show that addition of leptomycin B to human primary fibroblasts increased the levels of the p53 tumor suppressor protein. This was accompanied by the induction of p53-dependent transcriptional activity in cultured cells and an increase in the levels of the products of two p53-responsive genes) the p21(CIP1/WAF1) and HDM2 proteins. Leptomycin B induced the accumulation of p53 and HDM2 in the nucleus and the appearance of discrete nuclear aggregates containing both proteins. It has been reported that the transcriptional activity of p53 is modulated by its interaction with the HDM2 protein which also targets p53 for rapid degradation. Using a model cell. line conditionally expressing MDM2, the murine analogue of HDM2, we present evidence indicating that leptomycin B abrogates MDM2's role in p53 degradation and that the accumulation of p53 in distinct nuclear bodies is mediated by MDM2. Since HDM2 has recently been shown to contain a functional NES of the REV type, the most likely explanation for our results is that the effect of leptomycin B on HDM2 and p53 is due to the inhibition of nuclear export. The ability to visualize sites where p53 and HDM2 colocalize provides a new approach to study the association between the two proteins in vivo. These p53/HDM2-positive nuclear foci were found to also contain the U1A snRNP A and to be juxtaposed to the PML oncogenic domains. (C) 1999 Academic Press.