A transcriptional factor induced by HGF

HGF 诱导的转录因子

基本信息

批准号：
10470138
负责人：
TSUBOUCHI Hirohito
金额：
$ 7.68万
依托单位：
Miyazaki Medical College
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B).
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 2000
项目状态：
已结题

项目摘要

Growth factors induce cell proliferation in hepatocytes by stimulating progression through the G1 phase of the cell cycle. Induction of cyclin D1 expression is a critical feature of the mitogenic action of growth factors. Recently, we have reported that hepatocyte growth factor (HGF) and epidermal growth factor (EGF) additively stimulate a Ras/MAPK pathway, resulting in additive enhancement of cyclin D1 expression in primary cultured rat hepatocytes. In the present study, we isolated the rat cyclin D1 gene 5'-flanking sequence and identified two transcriptional regulatory regions by transient transfection studies using dRLh84 rat hepatoma cells. One (CD1CRE) was mapped to a potential cAMP-responsive element (CRE) at position -41 bp, while another (CD1E0.7) was located 753 bp upstream of the initiation site. Electrophoretic gel mobility shift assays (EMSAs) indicated that a protein binding to the CD1CRE was a CREB.In contrast, competition EMSA showed that CD1E0.7 did not interact with hepatocyte nuclear factor (HNF)-3β, nuclear factor of activated T cells (NF-AT), or the Ets family, although CD1E0.7 revealed high homology with a binding site for these nuclear factors through a computer search. Moreover, the specific interaction of CD1E0.7 with a protein extracted from primary cultured rat hepatocytes treated with HGF or EGF was detected. These results indicate that CREB binds to CD1CRE and mediates the activation of the cyclin D1 promoter in rat hepatoma cells, and suggest that CD1E0.7 is possibly occupied by a transcription factor induced by growth factors in rat hepatocytes.

生长因子通过刺激细胞周期的G1阶段的进展来诱导肝细胞中的细胞增殖。诱导细胞周期蛋白D1表达是生长因子有丝分裂作用的关键特征。最近，我们报道说，肝细胞生长因子（HGF）和表皮生长因子（EGF）添加刺激RAS/MAPK途径，从而导致细胞培养的大鼠肝细胞中Cyclin D1表达的进一步增强。在本研究中，我们通过使用DRLH84大鼠肝癌细胞进行了短暂翻译研究，分离了大鼠Cyclin d1基因5'-频序序列，并通过短暂翻译研究鉴定了两个转录调节区域。将一个（CD1CRE）映射到位置-41 bp的潜在营地响应元件（CRE），而另一个（CD1E0.7）位于倡议部位上游的753 bp（CD1E0.7）。电泳凝胶迁移率转移测定法（EMSA）表明，与CD1CRE结合的蛋白质是CREB。在相比之下，竞争EMSA表明，CD1E0.7没有与肝细胞核因子（HNF）-3β相互作用。搜索。此外，检测到CD1E0.7与用HGF或EGF处理的原代培养大鼠肝细胞提取的蛋白质的特异性相互作用。这些结果表明CREB与CD1CRE结合并介导大鼠肝癌细胞中细胞周期蛋白D1启动子的激活，并表明CD1E0.7可能被大鼠肝细胞生长因子引起的转录因子占据。