IDENTIFICATION OF ESSENTIAL GATA AND ETS BINDING MOTIFS WITHIN THE PROMOTER OF THE PLATELET GLYCOPROTEIN IB-ALPHA GENE
IDENTIFICATION OF ESSENTIAL GATA AND ETS BINDING MOTIFS WITHIN THE PROMOTER OF THE PLATELET GLYCOPROTEIN IB-ALPHA GENE
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DOI：
10.1074/jbc.270.41.24532
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发表时间：
1995-10-13
影响因子：
4.8
通讯作者：
WARE, J
中科院分区：
文献类型：
--
作者：
HASHIMOTO, Y;WARE, J
血小板糖蛋白（GP） Ib-M-V是一种多亚基粘附受体，支持血小板附着在血管损伤部位的血栓形成表面。该受体的先天性缺失导致与“巨型”血小板相关的出血性疾病，这种情况将该复合物的表达与血小板形态发生联系起来。研究确定了支持复合物α亚基（GP Ib α）表达的基本遗传因素。用编码荧光素酶的报告质粒转染人红细胞来评估GP Ib α启动子的活性，研究开始于转录起始位点延伸2,738个核苷酸5'的片段，并鉴定出253个核苷酸在人红细胞中保持完整的启动子活性。在非造血细胞系、人内皮细胞和HeLa细胞中，GP Ib α启动子活性不高于无启动子构建获得的背景水平，凝胶移位试验和定点突变研究确定了转录起始位点上游93和150个核苷酸的基本GATA和Ets结合基序，这一发现进一步证实了这些元件是巨核细胞基因表达的重要决定因素。结果确定了GP Ib α表达的基本顺式作用元件，并提供了与正常血小板释放到血液中的分子事件相一致的见解。
Platelet glycoprotein (GP) Ib-M-V is a multisubunit adhesion receptor that supports platelet attachment to thrombogenic surfaces at sites of vascular injury, The congenital absence of the receptor results in a bleeding disorder associated with ''giant'' platelets, a condition linking the expression of the complex to platelet morphogenesis, To understand better the expression of the GP Ib-IX-V complex, studies were undertaken to define the essential genetic elements supporting the expression of the alpha-subunit of the complex (GP Ib alpha). GP Ib alpha promoter activity was evaluated by transfection of human erythroleukemia cells with reporter plasmids coding for the enzyme, luciferase, Studies were initiated with a fragment extending 2,738 nucleotides 5' to the transcription start site and lead to the identification of 253 nucleotides retaining full promoter activity in human erythroleukemia cells. In cells of nonhematopoietic lineage, human endothelial and HeLa cells, the GP Ib alpha promoter activity was no greater than background levels obtained with promoterless constructs, Gel shift assays and site-directed mutagenesis studies defined essential GATA and Ets binding motifs 93 and 150 nucleotides upstream of the transcription start site, a finding which further substantiates these elements as important determinants of megakaryocytic gene expression. The results define essential cis-acting elements responsible for the expression of GP Ib alpha and provide insights into molecular events coinciding with the release of normal platelets into the bloodstream.