PDF(Pubmed)
Abstract：
The causative gene of Fukuyama congenital muscular dystrophy (fukutin) is involved in formation of the basement membrane through glycosylation of alpha-dystroglycan. However, there are other proposed functions that have not been fully understood. Using cultured astrocytes (1321N1), we found nuclear localization of fukutin and a positive relationship between fukutin expression and cell proliferation. Among potential proteins regulating cell proliferation, we focused on cyclin D1, by reverse-transcription polymerase chain reaction, Western blotting, immunocytochemistry, enzyme-linked immunosorbent assay (ELISA), and sandwich ELISA. Expression of cyclin D1 was significantly downregulated by fukutin knockdown and significantly upregulated by fukutin overexpression. Moreover, fukutin was proven to bind to the activator protein-1 (AP-1) binding site of cyclin D1 promoter, as well as the AP-1 component c-Jun. The c-Jun phosphorylation status was not significantly influenced by knockdown or overexpression of fukutin. The present results provide in vitro evidence for a novel function of fukutin, which participates in cell proliferation by enhancing cyclin D1 expression through forming a complex with AP-1. It is likely that fukutin is a potential cofactor of AP-1.
摘要：
福山先天性肌营养不良症（fukutin）的致病基因通过α-营养不良聚糖的糖基化参与基底膜的形成。然而,还有其他拟议的功能尚未得到充分理解。使用培养的星形胶质细胞（1321N1），我们发现了福库汀的核定位，福库汀的表达与细胞增殖之间存在正相关。在调节细胞增殖的潜在蛋白质中，我们通过逆转录聚合酶链反应专注于细胞周期蛋白D1，西方印迹,免疫细胞化学,酶联免疫吸附测定(ELISA),和夹心ELISA。cyclinD1的表达被fukutin敲低显著下调，而被fukutin过表达显著上调。此外，fukutin被证明与细胞周期蛋白D1启动子的激活蛋白1（AP-1）结合位点结合，以及AP-1组件c-Jun。fukutin的敲低或过表达对c-Jun磷酸化状态没有显着影响。本研究结果为福库汀的新功能提供了体外证据，它通过与AP-1形成复合物来增强细胞周期蛋白D1的表达而参与细胞增殖。福库丁很可能是AP-1的潜在辅因子。
