Funaoka K, Shindoh M, Yoshida K, Hanzawa M, Hida K, Nishikata S, Totsuka Y, Fujinaga K
Second Department of Oral Surgery, Hokkaido University School of Dentistry, Kita-ku, Sapporo, Japan.
Biochem Biophys Res Commun. 1997 Jul 9;236(1):79-82. doi: 10.1006/bbrc.1997.6909.
p21(Waf1/Cip1) is one of the key regulatory proteins in cell cycle, terminal differentiation, and apoptosis. Its promoter was shown to be transactivated by the wild-type p53 protein as well as in a p53-independent manner. In this report, we demonstrate that E1AF, an ets-related transcription factor, activates the human p21(Waf1/Cip1) promoter by interacting with the ets-binding sites located close to the two previously identified p53-responsive elements. Northern blot analysis revealed that p21(Waf1/Cip1) and E1AF were correlatively upregulated in response to cisplatin treatment in SiHa cells. Transient expression assays demonstrated that E1AF can activate the p21(Waf1/Cip1) promoter-driven luciferase reporter gene in SiHa cells. The p21(Waf1/Cip1) promoter activity was also increased in p53-null Saos2 osteosarcoma cells, but was markedly reduced when the ets-binding sites were deleted. These results indicate that E1AF positively regulates transcription from the p21(Waf1/Cip1) promoter in response to genotoxic stresses.
p21（Waf1/Cip1）是细胞周期、终末分化和细胞凋亡中的关键调节蛋白之一。其启动子已被证明可被野生型p53蛋白反式激活，也能以p53非依赖的方式被激活。在本报告中，我们证明E1AF（一种与ets相关的转录因子）通过与位于两个先前鉴定的p53反应元件附近的ets结合位点相互作用，激活人p21（Waf1/Cip1）启动子。Northern印迹分析显示，在SiHa细胞中，p21（Waf1/Cip1）和E1AF在顺铂处理后呈相关上调。瞬时表达分析表明，E1AF可在SiHa细胞中激活p21（Waf1/Cip1）启动子驱动的荧光素酶报告基因。在p53缺失的Saos2骨肉瘤细胞中，p21（Waf1/Cip1）启动子活性也增加，但当ets结合位点缺失时，活性明显降低。这些结果表明，E1AF在基因毒性应激反应中正向调节p21（Waf1/Cip1）启动子的转录。
