Peroxisome proliferator-activated receptor α induces rat sterol carrier protein x promoter activity through two peroxisome proliferator-response elements
Peroxisome proliferator-activated receptor α induces rat sterol carrier protein x promoter activity through two peroxisome proliferator-response elements
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DOI：
10.1016/s0303-7207(02)00300-3
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发表时间：
2003-07-31
影响因子：
4.1
通讯作者：
McLean, MP
中科院分区：
文献类型：
--
作者：
Lopez, D;Irby, RB;McLean, MP
甾醇载体蛋白 x (SCPx) 在脂肪酸过氧化物酶体氧化中发挥着关键作用。先前已在链脲佐菌素诱导的糖尿病大鼠中证明，SCPx 表达的诱导与血清脂肪酸和甘油三酯水平的升高有关。为了阐明糖尿病期间该基因表达的机制，克隆了大鼠 SCPx 启动子并分析了调控基序。对这个无 TATA 启动子的序列分析揭示了两个假定的过氧化物酶体增殖物响应元件 (PPRE) 结合基序，位于相对于翻译起始位点的 -134 和 -869 位置。为了检查过氧化物酶体增殖物激活受体 α (PPARα) 对此基因的影响，将包含两个 PPRE 基序的 935 bp SCPx 启动子克隆到氯霉素乙酰转移酶基因或荧光素酶基因前面，并与编码 PPARα 和类视黄醇 X 受体 (RXR) 的载体共转染到 HTB-9 细胞中。结果表明，在这两种情况下，PPARα 都能诱导 SCPx 启动子活性，RXR 和氯贝特可增强这种作用。此外，突变分析研究表明，两种 PPRE 都有助于 PPARα/RXRα 依赖性激活 SCPx 启动子。迁移率变动分析和超变动分析表明，含有 PPARα 的核提取物与两个 PPRE 基序结合。这项研究表明，与参与 β-氧化的其他基因类似，SCPx 转录可能通过 PPARα 受脂肪酸水平控制。 (C) 2002 Elsevier Science Ireland Ltd. 保留所有权利。
Sterol carrier protein x (SCPx) plays a critical role in the peroxisomal oxidation of fatty acids. It has been previously demonstrated in streptozotocin-induced diabetic rats that SCPx expression is induced in association with an elevation in serum fatty acid and triglyceride levels. To elucidate the mechanisms underlying the expression of this gene during diabetes, the rat SCPx promoter was cloned and analyzed for regulatory motifs. Sequence analysis of this TATA-less promoter revealed two putative peroxisomal-proliferator-response element (PPRE) binding motifs at positions -134 and - 869 relative to the translation start site. To examine peroxisomal-proliferator-activated receptor alpha (PPARalpha) effects on this gene, 935 bp of the SCPx promoter containing both PPRE motifs was cloned in front of the chloramphenicol acetyl-transferase gene or the luciferase gene and co-transfected into HTB-9 cells with vectors that encoded for PPARalpha and retinoid X receptor (RXR). The results indicate that PPARalpha was able to induce SCPx promoter activity in both cases, an effect that was enhanced by RXR and clofibrate. In addition, mutational analysis studies demonstrated that both PPREs contributed to the PPARalpha/RXRalpha-dependent activation of the SCPx promoter. Mobility shift assays and supershift analysis showed that nuclear extracts containing PPARalpha bound to the two PPRE motifs. This investigation indicates that similar to other genes involved in beta-oxidation, SCPx transcription may be controlled by fatty acid levels via PPARalpha. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved.