Ruijin Hospital, Shanghai Institute of Endocrinology, State Key Laboratory of Medical Genomics, Shanghai Jiao Tong University (SJTU) School of Medicine, Shanghai, China.
Mol Cell Endocrinol. 2010 Jun 10;321(2):239-44. doi: 10.1016/j.mce.2010.02.021. Epub 2010 Feb 21.
Mimecan is a protein of unknown function that is expressed in the pituitary. The aim of this study is to clarify the regulation and intracellular localisation of mimecan gene expression in the pituitary. With immunohistochemistry, we observed that mimecan protein was co-expressed with ACTH in pituitary corticotroph cells. Northern and Western blot analyses revealed that mimecan expression and secretion in corticotroph cells were up-regulated by treating AtT-20 cells with glucocorticoid. Meanwhile, mimecan expression in rat primary culture pituitary cells was also promoted by glucocorticoid. Co-incubation of AtT-20 cells with RU486 and glucocorticoid completely reversed the induction of mimecan gene expression by glucocorticoid. In addition, luciferase reporter assays showed that the -1474/+43 promoter region of mimecan was sufficient for glucocorticoid-responsive mimecan expression. These data collectively suggest that mimecan expressed in pituitary corticotroph cells is increased by glucocorticoid and that the up-regulation may be mediated by the classical GR pathways.
mimecan 是一种未知功能的蛋白，在垂体中表达。本研究旨在阐明 mimecan 基因在垂体中的表达调控和细胞内定位。通过免疫组织化学，我们观察到 mimecan 蛋白与 ACTH 在垂体促肾上腺皮质细胞中共同表达。Northern 和 Western blot 分析显示，糖皮质激素处理 AtT-20 细胞可上调 mimecan 的表达和分泌。同时，糖皮质激素也促进大鼠原代培养垂体细胞中 mimecan 的表达。AtT-20 细胞与 RU486 和糖皮质激素共同孵育可完全逆转糖皮质激素诱导的 mimecan 基因表达。此外，荧光素酶报告基因分析表明，mimecan 的-1474/+43 启动子区域足以介导糖皮质激素反应性 mimecan 表达。这些数据表明，糖皮质激素可增加垂体促肾上腺皮质细胞中表达的 mimecan，而上调可能是通过经典的 GR 途径介导的。
