GC factor 2 represses platelet-derived growth factor A-chain gene transcription and is itself induced by arterial injury
GC factor 2 represses platelet-derived growth factor A-chain gene transcription and is itself induced by arterial injury
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DOI：
10.1161/01.res.84.11.1258
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发表时间：
1999-06-11
影响因子：
20.1
通讯作者：
Johnson, AC
中科院分区：
文献类型：
--
作者：
Khachigian, LM;Santiago, FS;Johnson, AC
血小板衍生生长因子（PDGF）是多种细胞类型的有丝分裂原和化学引诱剂。编码PDGF A链（PDGF-A）和PDGF B链（PDGF-B）的基因位于不同的染色体上，并在转录水平上独立调控。诱导pdf - a表达的调控事件一直是许多研究的焦点，然而，抑制该基因转录的机制尚不清楚。在这项研究中，我们报道了新克隆的DNA结合因子GC因子的容量：！（GCF2），抑制由人类PDGF-A启动子驱动的表达。血管内皮细胞的5'缺失和瞬时共转染分析显示，GCF2的抑制是由位于PDCF-A启动子近端区域的核苷酸区域介导的。电泳迁移率转移试验表明，GCF2以特定的剂量依赖性方式结合到该区域。有趣的是，GCF2结合的位点与特异性蛋白-1 （Spl）和早期生长反应因子-1 （Egr-1）的位点重叠，锌指转录因子直接和诱导PDGF-A基因的基础表达。凝胶位移实验显示GCF2。与这些因子竞争与PDGF-A启动子相互作用。过表达GCF2抑制内源性PDGF-A在血管内皮细胞和平滑肌细胞中的表达。GCF2在培养细胞和大鼠颈动脉壁球囊损伤后的机械损伤中被诱导。时间过程研究显示，损伤后GCF2持续诱导，而PDGF-A水平急剧恢复到基线水平。GCF2可抑制平滑肌细胞的增殖，而添加外源性PDGF-AA可逆转这一作用。这些结果表明GCF2对PDGF-A的表达有负调控作用。这是第一个在大鼠血管壁诱导内源性转录抑制因子的报道。
Platelet-derived growth factor (PDGF) is a mitogen and chemoattractant for a wide variety of cell types. The genes encoding PDGF A chain (PDGF-A) and PDGF B chain(PDGF-B) reside on separate chromosomes and are independently regulated at the level of transcription. Regulatory events underlying inducible PDCF-A expression have been the focus of much investigation However, mechanisms that inhibit transcription of this gene are not well understood. In this study, we report the capacity of a newly cloned DNA binding factor, GC factor:! (GCF2), to repress expression driven by the human PDGF-A promoter. 5' Deletion and transient cotransfection analysis in vascular endothelial cells revealed that GCF2 repression is mediated by a nucleotide region located in the proximal region of the PDCF-A promoter. Electrophoretic mobility shift assays demonstrate that GCF2 binds to this region in a specific and dose-dependent manner. Interestingly, the site bound by GCF2 overlaps those for specificity protein-1 (Spl) and early growth response factor-1 (Egr-1), zinc finger transcription factors that direct basal and inducible expression of the PDGF-A gene. Gel shift experiments revealed that GCF2. competes with these factors for interaction with the PDGF-A promoter. Overexpression of GCF2 suppressed endogenous PDGF-A expression in vascular endothelial cells and smooth muscle cells. GCF2 was induced on mechanical injury of cells in culture as well as after balloon injury of the rat carotid artery wall. Time course studies revealed the sustained induction of GCF2 after injury while PDGF-A levels sharply returned to baseline. Smooth muscle cell proliferation was inhibited by GCF2, an effect reversed by the addition of exogenous PDGF-AA. These findings demonstrate negative regulation of PDGF-A expression by GCF2. This is the first report of the induction of an endogenous transcriptional repressor in the rat vessel wall.