Selective induction of cell cycle regulatory genes cdk1 (p34cdc2), cyclins A/B, and the tumor suppressor gene Rb in transformed cells by okadaic acid.
Selective induction of cell cycle regulatory genes cdk1 (p34cdc2), cyclins A/B, and the tumor suppressor gene Rb in transformed cells by okadaic acid.
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冈田酸选择性诱导转化细胞中的细胞周期调节基因 cdk1 (p34cdc2)、细胞周期蛋白 A/B 和肿瘤抑制基因 Rb。
DOI：
10.1002/jcp.1041640223
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发表时间：
1995
期刊：
影响因子：
--
通讯作者：
Bird,RC
中科院分区：
文献类型：
--
作者：
You,J;Bird,RC
编码CDK1(P34cdc2)、细胞周期蛋白A、细胞周期蛋白B和肿瘤抑制基因Rb的基因是细胞周期进程的基本调节基因，与转录因子E2F相关。其中许多蛋白的表达已被蛋白磷酸酶1/2A(PP1/PP2A)的特异性抑制剂冈田酸抑制，导致未转化但永生化的细胞生长停滞。我们研究了编码CDK1(P34cdc2)Cyclin A、Cyclin B、Rb、GAPDH、c-myc和组蛋白H4基因的mRNA在HeLa细胞中对冈田酸的敏感性，以确定转化是否改变了它们的调节。血清饥饿减缓了生长，降低了所有被测试基因的mRNA水平，但c-myc和GAPDH除外。当饥饿细胞随后暴露于19 NM冈田酸或10%血清时，细胞周期蛋白A、细胞周期蛋白B、细胞周期蛋白CDK1和Rb的mRNA水平显著增加，细胞周期蛋白A、细胞周期蛋白B、细胞周期蛋白CDK1和细胞周期蛋白Rb的mRNA水平显著增加，而c-myc和GAPDHmRNA水平基本不受影响。加入血清后，组蛋白H4mRNA水平和DNA合成速率显著增加，冈田酸对组蛋白H4mRNA水平和DNA合成速率的影响不明显。冈田酸还能有效地阻断G2/M期和S期指数级生长的HeLa细胞的增殖。尽管细胞周期特异性阻断，在去除冈田酸后，细胞周期蛋白CDK1、细胞周期蛋白A、细胞周期蛋白B、细胞周期蛋白B的mRNA水平升高，而H4基因的mRNA水平被抑制，并持续至少12小时。结果表明，细胞周期进程被阻断，编码转录因子E2F相关蛋白的几个细胞周期调控基因通过对冈田酸敏感的机制，可能是通过PP1/PP2A敏感机制，经历了mRNA水平的上调。来自转化细胞的数据与来自永生化但未转化细胞的数据形成了对比，在未转化细胞中，冈田酸也阻止了G2/M期的细胞周期进程，但抑制了这些基因的表达。这种对比可能与减少对生长因子的依赖和转化有关。©1995 Wiley-Liss公司
Genes encoding cdk1 (p34cdc2), cyclin A, cyclin B, and the tumor suppressor gene Rb are fundamental regulators of cell cycle progression which associate as a complex with the transcription factor E2F. Expression of many of these proteins has previously been shown to be repressed by okadaic acid, a specific inhibitor of protein phosphatases 1/2A (PP1/PP2A), resulting in growth arrest in nontransformed but immortilized cells. We have investigated levels of mRNA encoding cdk1 (p34cdc2) cyclin A, cyclin B, Rb, GAPDH,c‐myc, and histone H4 genes for sensitivity to okadaic acid in HeLa cells to determine if transformation altered their regulation. Serum starvation slowed growth and diminished mRNA levels for all genes tested exceptc‐mycand GAPDH. When starved cells were subsequently exposed to 19 nM okadaic acid or refed 10% serum, mRNA levels of cyclin A, cyclin B, cdk1, and Rb dramatically increased while mRNA levels of cyclin A, cyclin B, cdk1, and Rb dramatically increased while mRNA levels for c‐mycand GAPDH were largely unaffected. Histone H4 mRNA levels and the rate of DNA synthesis were greatly enhanced by serum addition but not affected apreciably by okadaic acid. Okadaic acid was also effective in blocking proliferation of exponentially growing HeLa cells at G2/M and S phase. Despite the cell cycle phase‐specific block, elevated mRNA levels for cdk1, cyclin A, cyclin B, Rb, and suppression of H4 mRNA levels were detected and persisted for at least 12 hr following okadaic acid removal. The results demonstrate that cell cycle progression is blocked and several cell cycle regulatory genes, encoding transcription factor E2F‐associated proteins, experience elevation of mRNA levels through mechanisms sensitive to okadaic acid likely through a PP1/PP2A‐sensitive mechanism. Data from transformed cells contrast with data from immortalized but nontransformed cells in which okadaic acid also blocks cell cycle progression during G2/M phase but suppresses expression of these genes. Such contrasts may be correlated with reduced growth factor dependence and transformation. © 1995 Wiley‐Liss, Inc.