Identification of the promoter region of the parathyroid hormone receptor gene responsible for transcriptional suppression by insulin-like growth factor-I
Identification of the promoter region of the parathyroid hormone receptor gene responsible for transcriptional suppression by insulin-like growth factor-I
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DOI：
10.1016/j.abb.2005.05.012
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发表时间：
2005-07-01
影响因子：
3.9
通讯作者：
Horiuchi, N
中科院分区：
文献类型：
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作者：
Kawane, T;Mimura, J;Horiuchi, N
我们使用大鼠成骨细胞样细胞系（UMR-106）研究了胰岛素样生长因子（IGF）-I诱导的甲状旁腺激素（PTH）/PTH相关蛋白受体（PTH 1 R）基因抑制。用特异性ERK信号通路抑制剂PD 98059和用显性负性或组成型活性形式的MAP激酶激酶转染的UMR-106细胞进行观察。IGF-I通过ERK 1/2 MAP激酶途径抑制PTH 1 R基因表达。我们克隆了大鼠PTH 1 R基因的8-kb启动子区域，并鉴定了U3启动子，这是大鼠成骨细胞中存在的两个主要IGF-I响应启动子之一。IGF-I抑制区在+1和+25之间，与先前描述的PTH抑制区（PTHSR）相同。凝胶迁移率改变检测到IGF-I降低了特异性DNA蛋白复合物。在构成PTH 1 R启动子区域的3.5kb以上的碱基序列中，涉及三个碱基序列（+1至+3）的突变完全消除了IGF-I的作用。因此，IGF-I信号可能作用于成骨细胞外显子U3转录起始位点，抑制转录活性。(C)2005年爱思唯尔公司All rights reserved.
We investigated parathyroid hormone (PTH)/PTH-related protein receptor (PTH1R) gene suppression induced by insulin-like growth factor (IGF)-I using a rat osteoblast-like cell line (UMR-106). Observations were made with PD98059, a specific ERK signaling pathway inhibitor, and UMR-106 cells transfected with dominant negative or constitutively active forms of MAP kinase kinase. IGF-I inhibited PTH1R gene expression via an ERK1/2 MAP kinase pathway. We cloned the 8-kb promoter region of the rat PTH1R gene and characterized the U3 promoter, a major IGF-I-responsive promoter among the two present in rat osteoblasts. The IGF-I-suppressive region was between +1 and +25, identical to the previously described PTH-suppressive region (PTHSR). Gel mobility-shift detected a specific DNA protein complex decreased by IGF-I. Mutation involving a three base sequence (+1 to +3) among more than 3.5 kb constituting the PTH1R promoter region completely abolished IGF-I action. Thus, IGF-I signaling may act at the osteoblast exon U3 transcription initiation site to repress the transcriptional activity. (C) 2005 Elsevier Inc. All rights reserved.