HNF3β and GATA-4 transactivate the liver-enriched homeobox gene, Hex
HNF3β and GATA-4 transactivate the liver-enriched homeobox gene, Hex
复制标题
DOI：
10.1016/s0378-1119(00)00082-2
复制
发表时间：
2000-04-04
期刊：
影响因子：
3.5
通讯作者：
Jacobs, HC
中科院分区：
文献类型：
--
作者：
Denson, LA;McClure, MH;Jacobs, HC
孤儿同源异型盒基因Hex具有有限的表达域，包括发育和成年小鼠肝脏。Hex在发育中的肝脏中表达，与叉头/翼状螺旋转录因子肝细胞核因子3 β（HNF 3 β）一致。虽然最近报道了小鼠Hex启动子的初步特征，但驱动肝脏表达的分子调节剂的身份尚不清楚。我们假设Hex启动子内假定的HNF 3 β和加塔-4元件将赋予肝脏富集表达。将一系列Hex启动子驱动的荧光素酶报告基因构建体转染到肝来源的HepG 2和成纤维细胞样Cos细胞+/-HNF 3 β或加塔表达质粒中。核苷酸-235/+22的Hex启动子区域在HepG 2和Cos细胞中赋予基础活性，核苷酸-103/+22的区域赋予肝脏富集活性。HNF 3 β和加塔-4通过位于nt-103/+22内的应答元件反式激活启动子，而Spl激活-235/+22构建体。HNF 3元件的突变显著降低了HepG 2细胞中的启动子活性，而该元件单独赋予HNF 3 β对异源启动子的响应性。进行电泳迁移率变动分析以确认转录因子：DNA结合。我们得出结论，HNF 3 β和加塔-4有助于肝脏富集的Hex表达。(C)2000 Elsevier Science B. V.保留所有权利。
The orphan homeobox gene, Hex, has a limited domain of expression which includes the developing and adult mouse liver. Hex is expressed in the developing liver coincident with the forkhead/winged helix transcription factor, Hepatocyte Nuclear Factor 3 beta (HNF3 beta). Although preliminary characterization of the mouse Hex promoter has recently been reported, the identity of the molecular regulators that drive liver expression is not known. We hypothesized that putative HNF3 beta and GATA-4 elements within the Hex promoter would confer liver-enriched expression. A series of Hex promoter-driven luciferase reporter constructs were transfected in liver-derived HepG2 and fibroblast-like Cos cells +/- HNF3 beta or GATA expression plasmids. The Hex promoter region from nt -235/+22 conferred basal activity in both HepG2 and Cos cells, with the region from -103/+22 conferring liver-enriched activity. HNF3 beta and GATA-4 transactivated the promoter via response elements located within nt -103/+22, whereas Spl activated the -235/+22 construct. Mutation of the HNF3 element significantly reduced promoter activity in HepG2 cells, whereas this element in isolation conferred HNF3 beta responsiveness to a heterologous promoter. Electrophoretic mobility shift assays were performed to confirm transcription factor:DNA binding. We conclude that HNF3 beta and GATA-4 contribute to liver-enriched expression of Hex. (C) 2000 Elsevier Science B.V. All rights reserved.