• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Molecular and Cellular Biology >Promoter and 11-kilobase upstream enhancer elements responsible for hepatoma cell-specific expression of the rat ornithine transcarbamylase gene.
【24h】

Promoter and 11-kilobase upstream enhancer elements responsible for hepatoma cell-specific expression of the rat ornithine transcarbamylase gene.

机译：启动子和11碱基对上游增强子元件负责大鼠鸟氨酸转氨甲酰酶基因的肝癌细胞特异性表达。

获取原文
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The gene for ornithine transcarbamylase (OTC; EC 2.1.3.3), a urea cycle enzyme, is expressed almost exclusively in the liver and small intestine. To identify DNA elements regulating transcription of the OTC gene in the liver, transient expression analysis was carried out by using hepatoma (HepG2) and nonhepatic (CHO) cell lines. The 1.3-kilobase 5'-flanking region of the rat OTC gene directed expression of the fused chloramphenicol acetyltransferase gene in HepG2 cells much more efficiently than in CHO cells. Analysis of deletion mutants of the 5'-flanking region in HepG2 cells revealed that there are at least one negative and two positive regulatory elements within the about 220-base-pair immediate 5'-flanking region. DNase I footprint analysis showed the presence of factors binding to these regulatory elements in nuclear extracts of rat liver and brain, and footprint profiles at the two positive elements exhibited liver-specific features. Transient expression analysis also revealed the existence of an enhancer region located 11 kilobases upstream of the transcription start site. The OTC enhancer was able to activate both its own and heterologous promoters in HepG2 but not in CHO cells. The enhancer was delimited to an about 230-base-pair region, and footprint analysis of this region revealed four protected areas. Footprint profiles at two of the four areas exhibited liver-specific features, and gel shift competition analysis showed that a factor(s) binding to the two liver-specific sites is related to C/EBP. These results suggest that both liver-specific promoter and enhancer elements regulate expression of the OTC gene through interaction with liver-specific factors binding to these elements.
机译：鸟氨酸转氨甲酰酶的基因（OTC; EC 2.1.3.3）是尿素循环酶，几乎只在肝脏和小肠中表达。为了鉴定调节肝脏中OTC基因转录的DNA元件，使用肝癌（HepG2）和非肝（CHO）细胞系进行了瞬时表达分析。大鼠OTC基因的1.3碱基5'侧翼区比HepG2细胞更有效地指导融合的氯霉素乙酰转移酶基因在HepG2细胞中的表达。分析HepG2细胞中5'侧翼区的缺失突变体后发现，在约220个碱基对的5'侧翼区中至少有一个负调控元件和两个正调控元件。 DNase I足迹分析表明在大鼠肝和脑的核提取物中存在与这些调节因子结合的因子，并且在两个阳性元素处的足迹分布显示出肝脏特有的特征。瞬时表达分析还显示存在位于转录起始位点上游11 kb处的增强子区域。 OTC增强子能够在HepG2中激活其自身和异源启动子，但在CHO细胞中却不能。增强子被划定为一个约230个碱基对的区域，该区域的足迹分析显示了四个保护区。四个区域中的两个区域的足迹分布显示出肝脏特有的特征，而凝胶位移竞争分析表明与两个肝脏特异位点结合的因子与C / EBP相关。这些结果表明，肝特异性启动子和增强子元件都通过与结合到这些元件的肝特异性因子的相互作用来调节OTC基因的表达。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号