Pan J, McEver R P
W. K. Warren Medical Research Institute, Department of Medicine, University of Oklahoma, Health Sciences Center, Oklahoma City 73104.
J Biol Chem. 1993 Oct 25;268(30):22600-8.
P-selectin, an adhesion receptor for leukocytes, is synthesized selectively by megakaryocytes and endothelial cells. We have cloned the 5'-flanking region of the human P-selectin gene and conducted a preliminary analysis of its features. As determined by primer extension, RNase protection, and anchored polymerase chain reaction cloning, there were multiple transcriptional initiation sites from -95 to -25 nucleotides relative to the start of protein-coding sequence. Transfection of bovine aortic endothelial cells with serially truncated segments of the 5'-flanking region linked to luciferase indicated that the sequence from -249 to -13 was sufficient to promote high level gene expression. Deletions to -197, -147, and -128 gradually reduced expression to basal levels, and further deletion to -100 abolished expression. The sequence from -309 to -13 supported only basal luciferase expression in COS-7, 293, or HeLa cells. Putative regulatory elements in the short 5'-flanking sequence included a CACCC sequence, two inverted repeats similar to binding sites for the ETS and NF-kappa B/rel families, a GATA motif, and a sequence related to the GT-IIC element of the SV40 enhancer. The GATA element was functional, as it bound recombinant GATA-2, and mutations in the core sequence impaired both nuclear protein binding and gene expression. These data suggest that the P-selectin gene is regulated by a combination of cis elements and their cognate transcription factors.
P-选择素是一种白细胞粘附受体,由巨核细胞和内皮细胞选择性合成。我们克隆了人类P-选择素基因的5'侧翼区,并对其特征进行了初步分析。通过引物延伸、核糖核酸酶保护和锚定聚合酶链反应克隆确定,相对于蛋白质编码序列的起始位置,从-95到-25个核苷酸处有多个转录起始位点。用与荧光素酶相连的5'侧翼区的系列截短片段转染牛主动脉内皮细胞表明,从-249到-13的序列足以促进高水平的基因表达。缺失到-197、-147和-128会逐渐将表达降低到基础水平,进一步缺失到-100则会消除表达。从-309到-13的序列在COS-7、293或HeLa细胞中仅支持基础荧光素酶表达。短5'侧翼序列中的推定调控元件包括一个CACCC序列、两个类似于ETS和NF-κB/rel家族结合位点的反向重复序列、一个GATA基序以及一个与SV40增强子的GT-IIC元件相关的序列。GATA元件具有功能,因为它能结合重组GATA-2,核心序列中的突变会损害核蛋白结合和基因表达。这些数据表明,P-选择素基因受顺式元件及其同源转录因子的组合调控。