Schedlich L J, Flanagan J L, Crofts L A, Gillies S A, Goldberg D, Morrison N A, Eisman J A
Bone and Mineral Research Group, Garvan Institute of Medical Research, St. Vincent's Hospital, Darlinghurst, Sydney, Australia.
J Bone Miner Res. 1994 Feb;9(2):143-52. doi: 10.1002/jbmr.5650090203.
Basic fibroblast growth factor (bFGF) has been detected in bone cells and stimulates osteoblast proliferation; however, its role in the regulation of bone metabolism remains speculative. We demonstrated that the human osteocalcin promoter is activated by bFGF when transfected into rat osteoblastic (ROS 17/2.8) cells. This effect is concentration dependent, with a twofold induction at 10 ng/ml detected after 20 h. The bFGF response is independent of both the 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3] and retinoic acid activation of the osteocalcin promoter. To identify the promoter sequences through which bFGF exerts its effect, we tested a series of promoter deletion constructs for their response to bFGF. Deletion of the upstream region between -673 and -588 bp results in a significant loss of induction. Gel-shift analysis demonstrates that proteins present in ROS 17/2.8 nuclear extracts bind specifically to these sequences. This region alone was unable to confer the bFGF response on a minimal osteocalcin or an heterologous promoter. However, sequences between -678 and -476 bp, which also includes the vitamin D response element (VDRE), were able to confer bFGF inducibility on both a minimal osteocalcin and a heterologous promoter. These data suggest that induction of the human osteocalcin promoter by bFGF requires the interaction of more than one sequence element.
在骨细胞中已检测到碱性成纤维细胞生长因子（bFGF），它可刺激成骨细胞增殖；然而，其在骨代谢调节中的作用仍具有推测性。我们证明，将人骨钙素启动子转染到大鼠成骨细胞（ROS 17/2.8）中时，它会被bFGF激活。这种效应具有浓度依赖性，在20小时后，10 ng/ml的bFGF可诱导其活性增加两倍。bFGF的反应独立于骨钙素启动子的1,25 - 二羟基维生素D3 [1,2(OH)2D3]和视黄酸激活。为了确定bFGF发挥作用的启动子序列，我们测试了一系列启动子缺失构建体对bFGF的反应。缺失 - 673至 - 588 bp之间的上游区域会导致诱导作用显著丧失。凝胶迁移分析表明，ROS 17/2.8核提取物中的蛋白质与这些序列特异性结合。仅该区域无法赋予最小骨钙素启动子或异源启动子bFGF反应。然而， - 678至 - 476 bp之间的序列，其中也包括维生素D反应元件（VDRE），能够赋予最小骨钙素启动子和异源启动子bFGF诱导性。这些数据表明，bFGF对人骨钙素启动子的诱导需要多个序列元件的相互作用。
