NPAT expression is regulated by E2F and is essential for cell cycle progression
NPAT expression is regulated by E2F and is essential for cell cycle progression
复制标题
DOI：
10.1128/mcb.23.8.2821-2833.2003
复制
发表时间：
2003-04-01
影响因子：
5.3
通讯作者：
Zhao, JY
中科院分区：
文献类型：
--
作者：
Gao, G;Bracken, AP;Zhao, JY
NPAT 是细胞周期蛋白 E-Cdk2 激酶的体内底物，被认为在哺乳动物细胞 G(1)/S 相转变和 S 期进入过程中组蛋白基因的协调转录激活中发挥着关键作用。在这里，我们表明，在生长刺激的细胞中，NPAT 转录在 G/S 期边界上调，并且 NPAT 启动子对 E2F 蛋白的激活做出反应。我们证明内源性 E2F 蛋白在体内与 NPAT 基因的启动子相互作用，并且 E2F1 的诱导表达刺激 NPAT mRNA 表达，支持了 NPAT 的表达受 E2F 调节的观点。一致地，我们发现 NPAT 启动子中的 E2F 位点是其在 G/S 相转变期间激活所必需的。此外，我们发现 NPAT 的表达加速了从静止状态释放的细胞进入 S 期。小干扰 RNA 双链体对 NPAT 表达的抑制会阻碍组织培养细胞中的细胞周期进程和组蛋白基因表达。因此，NPAT 是哺乳动物细胞细胞周期进展所需的重要 E2F 靶标。由于 NPAT 参与 S 期特异性组蛋白基因转录的调节，我们的研究结果表明 NPAT 将 E2F 与 S 期特异性组蛋白基因转录的激活联系起来。
NPAT is an in vivo substrate of cyclin E-Cdk2 kinase and is thought to play a critical role in coordinated transcriptional activation of histone genes during the G(1)/S-phase transition and in S-phase entry in mammalian cells. Here we show that NPAT transcription is up-regulated at the G,/S-phase boundary in growth-stimulated cells and that the NPAT promoter responds to activation by E2F proteins. We demonstrate that endogenous E2F proteins interact with the promoter of the NPAT gene in vivo and that induced expression of E2F1 stimulates NPAT mRNA expression, supporting the idea that the expression of NPAT is regulated by E2F. Consistently, we find that the E2F sites in the NPAT promoter are required for its activation during the G,/S-phase transition. Moreover, we show that the expression of NPAT accelerates S-phase entry in cells released from quiescence. The inhibition of NPAT expression by small interfering RNA duplexes impedes cell cycle progression and histone gene expression in tissue culture cells. Thus, NPAT is an important E2F target that is required for cell cycle progression in mammalian cells. As NPAT is involved in the regulation of S-phase-specific histone gene transcription, our findings indicate that NPAT links E2F to the activation of S-phase-specific histone gene transcription.