Atopy Research Center, Juntendo University School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan.
Mol Immunol. 2013 Mar;53(3):295-301. doi: 10.1016/j.molimm.2012.08.004. Epub 2012 Sep 16.
CD11c, a member of the β(2) integrin family of adhesion molecule, is expressed on the surface of myeloid lineages and activated lymphoid cells and forms a heterodimeric receptor with CD18. We analyzed the mouse CD11c promoter structure to elucidate the transcriptional regulation in dendritic cells (DCs). By reporter assay, the -84/-65 region was identified to be essential for activity of the mouse CD11c promoter in the mouse bone marrow-derived (BM) DCs and monocyte cell line RAW264.7. An electrophoretic mobility shift assay using a number of antibodies against transcription factors revealed that the target region was recognized by a complex including JunD and Fra2, which are transcription factors belonging to the AP-1 family. The direct interaction of JunD and Fra2 with the CD11c promoter was further confirmed by a chromatin immunoprecipitation assay using CD11c-positive cells purified from BMDCs. Finally, mouse JunD and/or Fra2 siRNA was introduced into BMDCs to evaluate the involvement of these factors against CD11c transcription and found that Fra2 siRNA reduced cell surface expression level of CD11c. These results indicate that AP-1 composed with JunD and Fra2 protein plays a primary role in enhancing the transcription level of the CD11c gene in DC.
CD11c 是β(2)整合素家族黏附分子的成员，表达于髓系细胞和活化的淋巴样细胞表面，与 CD18 形成异二聚体受体。我们分析了小鼠 CD11c 启动子结构，以阐明树突状细胞 (DC) 中的转录调控。通过报告基因分析，确定 -84/-65 区对于小鼠骨髓来源的 (BM) DC 和单核细胞系 RAW264.7 中的小鼠 CD11c 启动子活性是必需的。使用针对转录因子的多种抗体的电泳迁移率变动分析显示，目标区域被包括 JunD 和 Fra2 在内的复合物识别，JunD 和 Fra2 是属于 AP-1 家族的转录因子。使用从 BMDC 中纯化的 CD11c 阳性细胞进行染色质免疫沉淀分析进一步证实了 JunD 和 Fra2 与 CD11c 启动子的直接相互作用。最后，将小鼠 JunD 和/或 Fra2 siRNA 导入 BMDC 中，以评估这些因子对 CD11c 转录的影响，发现 Fra2 siRNA 降低了 CD11c 的细胞表面表达水平。这些结果表明，由 JunD 和 Fra2 蛋白组成的 AP-1 在增强 DC 中 CD11c 基因的转录水平方面起主要作用。
