Bril: A novel bone-specific modulator of mineralization
Bril: A novel bone-specific modulator of mineralization
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DOI：
10.1359/jbmr.080412
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发表时间：
2008-09-01
影响因子：
6.2
通讯作者：
Thomas, Gethin
中科院分区：
文献类型：
--
作者：
Moffatt, Pierre;Gaumond, Marie-Helene;Thomas, Gethin
在尝试使用信号捕获筛选方法来定义骨“分泌组”的过程中，我们鉴定了一个编码成骨细胞新的小膜蛋白的基因。虽然先前在计算机上鉴定为ifitm 5，但尚未对该基因进行定位或功能研究。我们的特点是表达模式和定位的基因在体外和体内，并评估其在体外基质矿化的作用。骨特异性和在矿化中所显示的作用使我们将基因重新命名为骨限制性ifitm样蛋白（Bril）。Bril编码一个14.8-kDa的1.34氨基酸蛋白，具有两个跨膜结构域。北方印迹分析显示骨特异性表达，在其他胚胎或成人组织中不表达。原位杂交和免疫组织化学在小鼠胚胎中的表达定位于发育中的骨。细胞系的筛选显示Bril表达在成骨细胞中最高，与基质成熟/矿化的开始相关，表明在骨形成中的作用。在矿化中的作用的功能性证据显示，在体外的腺病毒介导的Brit过表达和慢病毒介导的Bril shRNA敲低。Bril升高导致UMR 106和大鼠原代成骨细胞矿化的剂量依赖性增加。相反，MC 3 T3成骨细胞中Bril的敲低导致矿化减少。因此，我们确定Bril作为一种新的成骨细胞蛋白，并显示出在矿化中的作用，可能确定了一个新的骨形成的调控途径。
In the course of attempting to define the bone "secretome" using a signal-trap screening approach, we identified a gene encoding a small membrane protein novel to osteoblasts. Although previously identified in silico as ifitm5, no localization or functional studies had been undertaken on this gene. We characterized the expression patterns and localization of this gene in vitro and in vivo and assessed its role in matrix mineralization in vitro. The bone specificity and shown role in mineralization led us to rename the gene bone restricted ifitm-like protein (Bril). Bril encodes a 14.8-kDa 1.34 arnino acid protein with two transmembrane domains. Northern blot analysis showed bone-specific expression with no expression in other embryonic or adult tissues. In situ hybridization and immunohistochemistry in mouse embryos showed expression localized on the developing bone. Screening of cell lines showed Bril expression to be highest in osteoblasts, associated with the onset of matrix maturation/mineralization, suggesting a role in bone formation. Functional evidence of a role in mineralization was shown by adenovirus-mediated Brit overexpression and lentivirus-mediated Bril shRNA knockdown in vitro. Elevated Bril resulted in dose-dependent increases in mineralization in UMR106 and rat primary osteoblasts. Conversely, knockdown of Bril in MC3T3 osteoblasts resulted in reduced mineralization. Thus, we identified Bril as a novel osteoblast protein and showed a role in mineralization, possibly identifying a new regulatory pathway in bone formation.