Dai P H, Lan S S, Ding X H, Chao Y S
Merck Sharp & Dohme Research Laboratories, Rahway, New Jersey 07065-0900.
Eur J Biochem. 1990 Jun 20;190(2):305-10. doi: 10.1111/j.1432-1033.1990.tb15577.x.
To determine the cis- and trans-regulatory elements which control the expression of the apolipoprotein (apo) A-I gene, several DNA-protein binding assays, namely, gel mobility shift, exonuclease III protection, and exonuclease III footprinting assays, were employed to identify these elements. It is demonstrated that nuclear proteins of Hep G2 cells bind to five regions of DNA sequences between 252 and 149 base pairs upstream from the transcription initiation site of the rat apo A-I gene. Using South-Western blot analysis, it is determined that DNA-binding protein has a molecular mass of approximately 90 kDa. It is also shown that the DNA-binding protein was present in Hep G2 cells and rat livers but absent in rabbit livers. The results suggest that the lack of expression of the apo A-I gene in rabbit livers is due to the absence of this DNA-binding protein.
为了确定控制载脂蛋白（apo）A-I基因表达的顺式和反式调控元件，采用了几种DNA-蛋白质结合分析方法，即凝胶迁移率变动分析、核酸外切酶III保护分析和核酸外切酶III足迹分析来鉴定这些元件。结果表明，Hep G2细胞的核蛋白与大鼠apo A-I基因转录起始位点上游252至149个碱基对之间的五个DNA序列区域结合。通过蛋白质免疫印迹分析确定，DNA结合蛋白的分子量约为90 kDa。还表明，该DNA结合蛋白存在于Hep G2细胞和大鼠肝脏中，但在兔肝脏中不存在。结果提示，兔肝脏中apo A-I基因缺乏表达是由于这种DNA结合蛋白的缺失所致。
