The distal upstream region of insulin-like growth factor-binding protein-1 enhances its expression in endometrial stromal cells during decidualization
The distal upstream region of insulin-like growth factor-binding protein-1 enhances its expression in endometrial stromal cells during decidualization
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DOI：
10.1074/jbc.ra117.000234
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发表时间：
2018-04-06
影响因子：
4.8
通讯作者：
Sugino, Norihiro
中科院分区：
文献类型：
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作者：
Tamura, Isao;Jozaki, Kosuke;Sugino, Norihiro
我们先前已经证明，人子宫内膜间质细胞(ESCs)的蜕膜化导致全基因组范围内组蛋白-H3Lys-27(H3K27ac)乙酰化水平的增加。我们还报道了基因转录起始点上游或下游超过3kb的远端基因区域增加了H3K27ac的水平。胰岛素样生长因子结合蛋白-1(IGFBP-1)是一种特异的蜕膜化标志物，其上游远端区域(-4701~-7501bp)的H3K27ac水平升高。在这里，使用包含这个IGFBP-1上游区域的荧光素酶报告基因结构，我们检验了它是IGFBP-1增强子的假设。为了诱导蜕膜化，我们将ESCs与cAMP孵育，发现cAMP增加了荧光素酶的表达，表明蜕膜化增加了IGFBP-1上游区域的转录活性。此外，CRISPR/Cas9介导的该区域在HepG2细胞中的缺失显著降低了IGFBP-1的表达，证实了其作为IGFBP-1增强子的作用。芯片分析表明，cAMP增加了转录调控因子CCAAT增强子结合蛋白(C/EBP)、叉头盒O1(FOXO1)和p300对IGFBP-1增强子的募集。值得注意的是，C/EBP基因敲除抑制了cAMP对H3K27ac水平、染色质开放和IGFBP-1增强子上p300募集的刺激作用。这些结果表明，IGFBP-1上游的-4701~-7501bp区域是蜕膜化胚胎干细胞中IGFBP-1表达的增强子，C/EBP和FOXO1结合到该增强子区域上调IGFBP-1的表达，C/EBP通过招募p300到IGFBP-1增强子来诱导H3K27ac。
We have previously shown that decidualization of human endometrial stromal cells (ESCs) causes a genome-wide increase in the levels of acetylation of histone-H3 Lys-27 (H3K27ac). We also reported that the distal gene regions, more than 3 kb up- or downstream of gene transcription start sites have increased H3K27ac levels. Insulin-like growth factor-binding protein-1 (IGFBP-1) is a specific decidualization marker and has increased H3K27ac levels in its distal upstream region (-4701 to -7501 bp). Here, using a luciferase reporter gene construct containing this IGFBP-1 upstream region, we tested the hypothesis that it is an IGFBP-1 enhancer. To induce decidualization, we incubated ESCs with cAMP and found that cAMP increased luciferase expression, indicating that decidualization increased the transcriptional activity from the IGFBP-1 upstream region. Furthermore, CRISPR/Cas9-mediated deletion of this region in HepG2 cells significantly reduced IGFBP-1 expression, confirming its role as an IGFBP-1 enhancer. A ChIP assay revealed that cAMP increased the recruitment of the transcriptional regulators CCAAT enhancer-binding protein (C/EBP), forkhead box O1 (FOXO1), and p300 to the IGFBP-1 enhancer in ESCs. Of note, C/EBP knockdown inhibited the stimulatory effects of cAMP on the levels of H3K27ac, chromatin opening, and p300 recruitment at the IGFBP-1 enhancer. These results indicate that the region -4701 to -7501 bp upstream of IGFBP-1 functions as an enhancer for IGFBP-1 expression in ESCs undergoing decidualization, that C/EBP and FOXO1 bind to the enhancer region to up-regulate IGFBP-1 expression, and that C/EBP induces H3K27ac by recruiting p300 to the IGFBP-1 enhancer.