Marrugo J, Marsh D G, Ghosh B
Division of Clinical Immunology, Johns Hopkins University School of Medicine, Baltimore, MD 21224, U.S.A.
Mol Immunol. 1996 Oct;33(14):1119-25. doi: 10.1016/s0161-5890(96)00073-9.
The conserved lymphokine elements-0 (CLE0) in the IL5 promoter is essential for the expression of IL-5. Here, we report the cloning and expression of a cDNA encoding a novel CLE0-binding protein, CLEBP-1 from a mouse Th2 clone, D10.G4.1. Interestingly, it was found that the CLEBP1 cDNA sequence was almost identical to the sequences of known high mobility group-1 (HMG1) cDNAs. When expressed as a recombinant fusion protein in Escherichia coli, CLEBP-1 was shown to bind to the IL5-CLE0 element in electrophoretic mobility-shift assays (EMSA) and southwestern blot analysis. The CLEBP-1 fusion protein cross-reacts with and-HMG-1/2 in Western blot analysis. It also binds to the CLE0 elements of IL4, GMCSF and GCSF genes. CLEBP-1 and closely related HMG-1 and HMG-2 proteins may play key roles in facilitating the expression of the lymphokine genes that contain CLE0 elements.
白细胞介素5（IL-5）启动子中的保守淋巴细胞因子元件0（CLE0）对于IL-5的表达至关重要。在此，我们报道了从小鼠Th2克隆D10.G4.1中克隆并表达一种编码新型CLE0结合蛋白CLEBP-1的cDNA。有趣的是，发现CLEBP1 cDNA序列与已知的高迁移率族蛋白1（HMG1）cDNA序列几乎相同。当在大肠杆菌中作为重组融合蛋白表达时，在电泳迁移率变动分析（EMSA）和蛋白质印迹分析中，CLEBP-1显示出与IL5-CLE0元件结合。在蛋白质印迹分析中，CLEBP-1融合蛋白与α-HMG-1/2发生交叉反应。它还与IL4、GMCSF和GCSF基因的CLE0元件结合。CLEBP-1以及与之密切相关的HMG-1和HMG-2蛋白可能在促进含有CLE0元件的淋巴细胞因子基因的表达中起关键作用。
