Transcriptional regulation of CHI3L1, a gene for late stages of macrophage differentiation
Transcriptional regulation of CHI3L1, a gene for late stages of macrophage differentiation
复制标题
DOI：
10.1074/jbc.m306792200
复制
发表时间：
2003-11-07
影响因子：
4.8
通讯作者：
Krause, SW
中科院分区：
文献类型：
--
作者：
Rehli, M;Niller, HH;Krause, SW
CHI 3L 1基因的蛋白产物，人软骨39-kDa糖蛋白（HC-gp 39），是一种组织限制性几丁质结合凝集素，是糖基水解酶家族18的成员。与许多其他单核细胞/巨噬细胞标志物相反，其表达在单核细胞中不存在，并且在人巨噬细胞分化的晚期阶段被强烈诱导。为了深入了解其在巨噬细胞中的细胞类型限制和成熟相关表达的分子机制，我们开始了对近端HC-gp 39启动子的详细研究。对巨噬细胞样THP-1细胞中报告基因构建体的缺失分析定位了一个区域，该区域指导巨噬细胞特异性报告基因的高水平表达，该区域与主要转录起始位点相邻约300 bp。启动子序列包含几个已知因子的共有结合位点，并且在凝胶迁移试验中可检测到核PU. 1、Sp1、Sp3、USF、AML-1和C/EBP蛋白的特异性结合。硫酸二甲酯的体内足迹分析表明，与单核细胞相比，巨噬细胞中相应序列的保护增强。转录因子结合位点的突变分析表明，一个单一的Sp1结合位点在调节HC-gp 39启动子活性的主导作用。此外，使用单核细胞和巨噬细胞的核提取物的凝胶迁移试验表明，核Sp1的结合，但不是Sp3，在巨噬细胞分化过程中显着增加。我们的研究结果进一步强调了Sp1在巨噬细胞基因调控中的重要作用。
The protein product of the CHI3L1 gene, human cartilage 39-kDa glycoprotein (HC-gp39), is a tissue-restricted, chitin-binding lectin and member of glycosyl hydrolase family 18. In contrast to many other monocyte/macrophage markers, its expression is absent in monocytes and strongly induced during late stages of human macrophage differentiation. To gain insights into the molecular mechanisms underlying its cell type-restricted and maturation-associated expression in macrophages, we initiated a detailed study of the proximal HC-gp39 promoter. Deletion analysis of reporter constructs in macrophage-like THP-1 cells localized a region directing high levels of macrophage-specific reporter gene expression to similar to300 bp adjacent to the major transcriptional start site. The promoter sequence contained consensus binding sites for several known factors, and specific binding of nuclear PU.1, Sp1, Sp3, USF, AML-1, and C/EBP proteins was detectable in gel shift assays. In vivo footprinting assays with dimethyl sulfate demonstrate that the protection of corresponding sequences was enhanced in macrophages compared with monocytes. Mutational analysis of transcription factor binding sites indicated a predominant role for a single Sp1 binding site in regulating HC-gp39 promoter activity. In addition, gel shift assays using nuclear extracts of monocytes and macrophages demonstrated that the binding of nuclear Sp1, but not Sp3, markedly increases during macrophage differentiation. Our results further highlight the important role of Sp1 in macrophage gene regulation.