Activation of receptor activator of NF-κB ligand gene expression by 1,25-dihydroxyvitamin D3 is mediated through multiple long-range enhancers
Activation of receptor activator of NF-κB ligand gene expression by 1,25-dihydroxyvitamin D3 is mediated through multiple long-range enhancers
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DOI：
10.1128/mcb.00353-06
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发表时间：
2006-09-01
影响因子：
5.3
通讯作者：
Pike, J. Wesley
中科院分区：
文献类型：
--
作者：
Kim, Sungtae;Yamazaki, Miwa;Pike, J. Wesley
RANKL是一种肿瘤坏死因子（TNF）样因子，由间充质细胞、成骨细胞衍生物和T细胞分泌，是破骨细胞发生所必需的。在成骨细胞中，RANKL的表达受两种主要的降钙激素，1,25-二羟基维生素D-3 [1,25(OH)(2)D-3]和甲状旁腺激素（PTH）以及几种炎症/破骨细胞因子的调节；这种调控的分子机制尚不清楚。为了确定这种机制，我们使用染色质免疫沉淀（ChIP）衍生的DNA与维生素D受体（VDR）和类视黄醇X受体（RXR）的抗体沉淀，筛选了一个DNA微阵列，以50 bp的分辨率覆盖整个小鼠RankL基因位点。RankL基因上有5个二聚体相互作用位点，分别位于TSS上游16、22、60、69和76 kb。这些区域不仅含有VDR和RXR的结合位点，还含有糖皮质激素受体（GR）的结合位点。这些区域中最遥远的区域被称为远端控制区（RL-DCR），该区域同时具有vdr依赖性1,25(OH)2D3和gr依赖性糖皮质激素（GC）反应。我们将这些活性映射到一个不寻常但功能活跃的维生素D反应元件和几个潜在的GC反应元件，这些反应元件位于RL-DCR中更广泛的区域。人类RANKL基因中的一个进化保守区域含有类似的维生素D反应元件，并表现出相同的行为。重要的是，RankL基因的激素激活也与染色质修饰和RNA聚合酶11募集有关。我们的研究表明，1,25(OH)(2)D-3对RankL基因表达的调控是复杂的，至少有五个远端区域介导，其中一个包含能够介导直接转录激活的特定元件。
RANKL is a tumor necrosis factor (TNF)-like factor secreted by mesenchymal cells, osteoblast derivatives, and T cells that is essential for osteoclastogenesis. In osteoblasts, RANKL expression is regulated by two major calcemic hormones, 1,25-dihydroxyvitamin D-3 [1,25(OH)(2)D-3] and parathyroid hormone (PTH), as well as by several inflammatory/osteoclastogenic cytokines; the molecular mechanisms for this regulation are unclear. To identify such mechanisms, we screened a DNA microarray which tiled across the entire mouse RankL gene locus at a 50-bp resolution using chromatin immunoprecipitation (ChIP)-derived DNA precipitated with antibodies to the vitamin D receptor (VDR) and the retinoid X receptor (RXR). Five sites of dimer interaction were observed on the RankL gene centered at 16, 22, 60, 69, and 76 kb upstream of the TSS. These regions contained binding sites for not only VDR and RXR, but also the glucocorticoid receptor (GR). The most distant of these regions, termed the distal control region (RL-DCR), conferred both VDR-dependent 1,25(OH)2D3 and GR-dependent glucocorticoid (GC) responses. We mapped these activities to an unusual but functionally active vitamin D response element and to several potential GC response elements located over a more extensive region within the RL-DCR. An evolutionarily conserved region within the human RANKL gene contained a similar vitamin D response element and exhibited an equivalent behavior. Importantly, hormonal activation of the RankL gene was also associated with chromatin modification and RNA polymerase 11 recruitment. Our studies demonstrate that regulation of RankL gene expression by 1,25(OH)(2)D-3 is complex and mediated by at least five distal regions, one of which contains a specific element capable of mediating direct transcriptional activation.