Zhang B, Marcus S L, Sajjadi F G, Alvares K, Reddy J K, Subramani S, Rachubinski R A, Capone J P
Department of Biochemistry, McMaster University, Hamilton, Ontario, Canada.
Proc Natl Acad Sci U S A. 1992 Aug 15;89(16):7541-5. doi: 10.1073/pnas.89.16.7541.
Ciprofibrate, a hypolipidemic drug that acts as a peroxisome proliferator, induces the transcription of genes encoding peroxisomal beta-oxidation enzymes. To identify cis-acting promoter elements involved in this induction, 5.8 kilobase pairs of promoter sequence from the gene encoding rat peroxisomal enoyl-CoA hydratase/3-hydroxyacyl-CoA dehydrogenase (EC 4.2.1.17/EC 1.1.1.35) was inserted upstream of a luciferase reporter gene. Transfection of this expression vector into rat hepatoma H4IIEC3 cells in the presence of ciprofibrate resulted in a 5- to 10-fold, cell type-specific increase in luciferase activity as compared to cells transfected in the absence of drug. A peroxisome proliferator-responsive element (PPRE) was localized to a 196-nucleotide region centered at position -2943 from the transcription start site. This PPRE conferred ciprofibrate responsiveness on a heterologous promoter and functioned independently of orientation or position. Gel retardation analysis with nuclear extracts demonstrated that ciprofibrate-treated or untreated H4IIEC3 cells, but not HeLa cells or monkey kidney cells, contained sequence-specific DNA binding factors that interact with the PPRE. These results have implications for understanding the mechanisms of coordinated transcriptional induction of genes encoding peroxisomal proteins by hypolipidemic agents and other peroxisome proliferators.
环丙贝特是一种作为过氧化物酶体增殖剂的降血脂药物，可诱导编码过氧化物酶体β-氧化酶的基因转录。为了鉴定参与这种诱导作用的顺式作用启动子元件，将来自大鼠过氧化物酶体烯酰辅酶A水合酶/3-羟酰基辅酶A脱氢酶（EC 4.2.1.17/EC 1.1.1.35）基因的5.8千碱基对启动子序列插入到荧光素酶报告基因的上游。在环丙贝特存在的情况下，将该表达载体转染到大鼠肝癌H4IIEC3细胞中，与未用药物转染的细胞相比，荧光素酶活性有5至10倍的细胞类型特异性增加。一个过氧化物酶体增殖剂反应元件（PPRE）定位于一个以转录起始位点-2943位置为中心的196个核苷酸区域。该PPRE赋予异源启动子对环丙贝特的反应性，并且其功能不受方向或位置的影响。用核提取物进行的凝胶阻滞分析表明，用环丙贝特处理或未处理的H4IIEC3细胞，但不是HeLa细胞或猴肾细胞，含有与PPRE相互作用的序列特异性DNA结合因子。这些结果对于理解降血脂药物和其他过氧化物酶体增殖剂对编码过氧化物酶体蛋白的基因进行协同转录诱导的机制具有重要意义。
