Jackson Audrey A, Cronin Katherine R, Zachariah Roshini, Carew Josephine A
Veterans Affairs Boston Healthcare System, West Roxbury, Massachusetts 02132, USA.
J Biol Chem. 2007 Oct 26;282(43):31156-65. doi: 10.1074/jbc.M704694200. Epub 2007 Aug 3.
Expression of the human coagulation factor VII (FVII) gene by hepatoma cells was modulated in concert with levels of glucose and insulin in the culture medium. In low glucose medium without insulin, amounts of both FVII mRNA and secreted FVII protein were coordinately increased; in the presence of glucose with insulin, both were decreased. Analysis of the FVII promoter showed that these effects could be reproduced in a reporter-gene system, and a small promoter element immediately upstream of the translation start site of the gene, which mediated these effects, was identified. Mutation of this element largely abrogated the glucose/insulin-responsive change in expression of the reporter gene. Several members of the CCAAT/enhancer-binding protein family were found to be capable of binding the identified sequence element but not the mutated element. The expression of a FVII minigene directed by a segment of the native FVII promoter responded to co-expressed activating and inhibiting forms of CCAAT/enhancer-binding protein beta.
肝癌细胞中人凝血因子VII(FVII)基因的表达与培养基中葡萄糖和胰岛素的水平协同调节。在无胰岛素的低糖培养基中,FVII mRNA和分泌的FVII蛋白的量均协同增加;在有葡萄糖和胰岛素存在的情况下,两者均减少。对FVII启动子的分析表明,这些效应可以在报告基因系统中重现,并且鉴定出了该基因翻译起始位点上游紧邻的一个小启动子元件,它介导了这些效应。该元件的突变在很大程度上消除了报告基因表达中葡萄糖/胰岛素反应性变化。发现CCAAT/增强子结合蛋白家族的几个成员能够结合鉴定出的序列元件,但不能结合突变元件。由天然FVII启动子片段指导的FVII小基因的表达对共表达的CCAAT/增强子结合蛋白β的激活和抑制形式有反应。