Nucleolin is involved in interferon regulatory factor-2-dependent transcriptional activation
Nucleolin is involved in interferon regulatory factor-2-dependent transcriptional activation
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DOI：
10.1038/sj.onc.1209522
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发表时间：
2006-08-24
期刊：
影响因子：
8
通讯作者：
Yamaguchi, K.
中科院分区：
文献类型：
--
作者：
Masumi, A.;Fukazawa, H.;Yamaguchi, K.
我们之前已经证明，干扰素调节因子-2(IRF-2)是以细胞生长依赖的方式乙酰化的，这使得它能够促进细胞生长调节启动子的转录。为了阐明IRF-2乙酰化的功能，我们研究了与乙酰化IRF-2相关的蛋白质。在293T细胞中，p300/CBP相关因子(PCAF)的转染增强了IRF-2的乙酰化。在同时转染IRF-2和PCAF的细胞中，IRF-2与内源性核仁素结合，而当IRF-2被PCAF组蛋白乙酰转移酶(HAT)缺失突变体转染组蛋白乙酰转移酶(HAT)缺失突变体时，IRF-2与内源性核仁素的结合很小。在使用稳定转染体的下拉实验中，乙酰化缺陷突变体IRF-2(IRF-2K75R)招募核仁的程度比野生型IRF-2小得多，这表明核仁优先与乙酰化的IRF-2结合。在PCAF存在的情况下，核仁素增强了NIH3T3细胞中依赖IRF-2的H4启动子的活性。用siRNA敲除核仁素可降低IRF-2/PCAF介导的启动子活性。染色质免疫沉淀分析表明，PCAF基因的转染增加了核仁素与H4启动子结合的IRF-2的结合。我们得出结论，核素被招募到乙酰化的IRF-2上，从而有助于对控制细胞生长至关重要的基因调控。
We have previously shown that interferon regulatory factor-2 (IRF-2) is acetylated in a cell growth-dependent manner, which enables it to contribute to the transcription of cell growth-regulated promoters. To clarify the function of acetylation of IRF-2, we investigated the proteins that associate with acetylated IRF-2. In 293T cells, the transfection of p300/CBP-associated factor (PCAF) enhanced the acetylation of IRF-2. In cells transfected with both IRF-2 and PCAF, IRF-2 associated with endogenous nucleolin, while in contrast, minimal association was observed when IRF-2 was transfected with a PCAF histone acetyl transferase (HAT) deletion mutant. In a pull-down experiment using stable transfectants, acetylation-defective mutant IRF-2 (IRF-2K75R) recruited nucleolin to a much lesser extent than wild-type IRF-2, suggesting that nucleolin preferentially associates with acetylated IRF-2. Nucleolin in the presence of PCAF enhanced IRF-2-dependent H4 promoter activity in NIH3T3 cells. Nucleolin knock-down using siRNA reduced the IRF-2/PCAF-mediated promoter activity. Chromatin immunoprecipitation analysis indicated that PCAF transfection increased nucleolin binding to IRF-2 bound to the H4 promoter. We conclude that nucleolin is recruited to acetylated IRF-2, thereby contributing to gene regulation crucial for the control of cell growth.