Shimizu Makoto, Takeshita Ayumi, Tsukamoto Toshiro, Gonzalez Frank J, Osumi Takashi
Department of Life Science, Graduate School of Science, Himeji Institute of Technology, Kamigori, Hyogo 678-1297, Japan.
Mol Cell Biol. 2004 Feb;24(3):1313-23. doi: 10.1128/MCB.24.3.1313-1323.2004.
Most cis-acting regulatory elements have generally been assumed to activate a single nearby gene. However, many genes are clustered together, raising the possibility that they are regulated through a common element. We show here that a single peroxisome proliferator response element (PPRE), located between the mouse PEX11 alpha and perilipin genes, confers on both genes activation by peroxisome proliferator-activated receptor alpha (PPAR alpha) and PPAR gamma. A functional PPRE 8.4 kb downstream of the promoter of PEX11 alpha, a PPAR alpha target gene, was identified by a gene transfection study. This PPRE was positioned 1.9 kb upstream of the perilipin gene and also functioned with the perilipin promoter. In addition, this PPRE, when combined with the natural promoters of the PEX11 alpha and perilipin genes, conferred subtype-selective activation by PPAR alpha and PPAR gamma 2. The PPRE sequence specifically bound to the heterodimer of RXR alpha and PPAR alpha or PPAR gamma 2, as assessed by electrophoretic gel mobility shift assays. Furthermore, tissue-selective binding of PPAR alpha and PPAR gamma to the PPRE was demonstrated in hepatocytes and adipocytes, respectively, by chromatin immunoprecipitation assay. Hence, the expression of these genes is induced through the same PPRE in the liver and adipose tissue, where the two PPAR subtypes are specifically expressed.
大多数顺式作用调节元件通常被认为只能激活一个附近的基因。然而,许多基因是聚集在一起的,这就增加了它们通过一个共同元件进行调节的可能性。我们在此表明,位于小鼠PEX11α基因和围脂滴蛋白基因之间的单个过氧化物酶体增殖物反应元件(PPRE),可使这两个基因都受到过氧化物酶体增殖物激活受体α(PPARα)和PPARγ的激活。通过基因转染研究,在PPARα靶基因PEX11α启动子下游8.4 kb处鉴定出一个功能性PPRE。该PPRE位于围脂滴蛋白基因上游1.9 kb处,也能与围脂滴蛋白启动子起作用。此外,当这个PPRE与PEX11α基因和围脂滴蛋白基因的天然启动子结合时,可赋予PPARα和PPARγ2亚型选择性激活作用。通过电泳凝胶迁移率变动分析评估,PPRE序列能特异性结合RXRα与PPARα或PPARγ2的异二聚体。此外,通过染色质免疫沉淀分析分别在肝细胞和脂肪细胞中证明了PPARα和PPARγ与PPRE的组织选择性结合。因此,这些基因的表达是通过肝脏和脂肪组织中相同的PPRE诱导的,这两种PPAR亚型在这些组织中特异性表达。