Li Pingxin, Yao Hongjie, Zhang Zhiqiang, Li Ming, Luo Yuan, Thompson Paul R, Gilmour David S, Wang Yanming
Center for Gene Regulation, Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA 16802, USA.
Mol Cell Biol. 2008 Aug;28(15):4745-58. doi: 10.1128/MCB.01747-07. Epub 2008 May 27.
Histone Arg methylation has been correlated with transcriptional activation of p53 target genes. However, whether this modification is reversed to repress the expression of p53 target genes is unclear. Here, we report that peptidylarginine deiminase 4, a histone citrullination enzyme, is involved in the repression of p53 target genes. Inhibition or depletion of PAD4 elevated the expression of a subset of p53 target genes, including p21/CIP1/WAF1, leading to cell cycle arrest and apoptosis. Moreover, the induction of p21, cell cycle arrest, and apoptosis by PAD4 depletion is p53 dependent. Protein-protein interaction studies showed an interaction between p53 and PAD4. Chromatin immunoprecipitation assays showed that PAD4 is recruited to the p21 promoter in a p53-dependent manner. RNA polymerase II (Pol II) activities and the association of PAD4 are dynamically regulated at the p21 promoter during UV irradiation. Paused RNA Pol II and high levels of PAD4 were detected before UV treatment. At early time points after UV treatment, an increase of histone Arg methylation and a decrease of citrullination were correlated with a transient activation of p21. At later times after UV irradiation, a loss of RNA Pol II and an increase of PAD4 were detected at the p21 promoter. The dynamics of RNA Pol II activities after UV treatment were further corroborated by permanganate footprinting. Together, these results suggest a role of PAD4 in the regulation of p53 target gene expression.
组蛋白精氨酸甲基化与p53靶基因的转录激活相关。然而，这种修饰是否会被逆转以抑制p53靶基因的表达尚不清楚。在此，我们报告肽基精氨酸脱亚氨酶4（一种组蛋白瓜氨酸化酶）参与p53靶基因的抑制。抑制或缺失PAD4会提高包括p21/CIP1/WAF1在内的一部分p53靶基因的表达，导致细胞周期停滞和凋亡。此外，PAD4缺失诱导的p21表达、细胞周期停滞和凋亡是p53依赖性的。蛋白质-蛋白质相互作用研究显示p53与PAD4之间存在相互作用。染色质免疫沉淀分析表明，PAD4以p53依赖性方式被招募到p21启动子。在紫外线照射期间，RNA聚合酶II（Pol II）活性和PAD4的结合在p21启动子处受到动态调节。在紫外线处理前检测到暂停的RNA Pol II和高水平的PAD4。在紫外线处理后的早期时间点，组蛋白精氨酸甲基化增加和瓜氨酸化减少与p21的短暂激活相关。在紫外线照射后的后期，在p21启动子处检测到RNA Pol II丢失和PAD4增加。紫外线处理后RNA Pol II活性的动态变化通过高锰酸盐足迹法得到进一步证实。总之，这些结果表明PAD4在p53靶基因表达调控中发挥作用。
