Bmp2 transcription in osteoblast progenitors is regulated by a distant 3′ enhancer located 156.3 kilobases from the promoter
Bmp2 transcription in osteoblast progenitors is regulated by a distant 3′ enhancer located 156.3 kilobases from the promoter
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DOI：
10.1128/mcb.01609-06
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发表时间：
2007-04-01
影响因子：
5.3
通讯作者：
Mortlock, Douglas P.
中科院分区：
文献类型：
--
作者：
Chandler, Ronald L.;Chandler, Kelly J.;Mortlock, Douglas P.
骨形态发生蛋白2（由Bmp 2编码）是成骨细胞分化和骨形成的重要信号配体，也是骨质疏松症的遗传风险因子。为了初步调查小鼠Bmp 2基因侧翼的大基因组区域的顺式调节功能，将延伸到基因上游和下游的两个细菌人工染色体（BAC）克隆工程化以包含lacZ报告盒，并在转基因小鼠中进行测试。每个BAC克隆指导正常Bmp 2表达模式的不同子集，表明远端Bmp 2调控元件的模块化排列。引人注目的是，在分化的成骨细胞以及牙芽、毛基板、肾和其它组织中Bmp 2表达所需的调节序列位于启动子的3 '端的53个以上的酶。通过测试在这个遥远的3 '区域具有工程化缺失的BAC，我们将这些调控元件解析到单独的位置，并更精确地细化成骨细胞祖细胞元件的位置。最后，一个保守的成骨细胞祖细胞增强子被确定在一个656-bp的序列内，位于启动子3 '端的156.3bp处。这种增强子的鉴定应允许进一步研究成骨细胞分化过程中控制Bmp 2转录的上游调控机制，并与进一步研究Bmp 2作为骨质疏松症的候选危险因子基因有关。
Bone morphogenetic protein 2 (encoded by Bmp2) has been implicated as an important signaling ligand for osteoblast differentiation and bone formation and as a genetic risk factor for osteoporosis. To initially survey a large genomic region flanking the mouse Bmp2 gene for cis-regulatory function, two bacterial artificial chromosome (BAC) clones that extend far upstream and downstream of the gene were engineered to contain a lacZ reporter cassette and tested in transgenic mice. Each BAC clone directs a distinct subset of normal Bmp2 expression patterns, suggesting a modular arrangement of distant Bmp2 regulatory elements. Strikingly, regulatory sequences required for Bmp2 expression in differentiating osteoblasts, as well as tooth buds, hair placodes, kidney, and other tissues, are located more than 53 kilobases 3 ' to the promoter. By testing BACs with engineered deletions across this distant 3 ' region, we parsed these regulatory elements into separate locations and more closely refined the location of the osteoblast progenitor element. Finally, a conserved osteoblast progenitor enhancer was identified within a 656-bp sequence located 156.3 kilobases 3 ' from the promoter. The identification of this enhancer should permit further investigation of upstream regulatory mechanisms that control Bmp2 transcription during osteoblast differentiation and are relevant to further studies of Bmp2 as a candidate risk factor gene for osteoporosis.