Hepatic lipase promoter activity is reduced by the C-480T and G-216A substitutions present in the common LIPC gene variant, and is increased by Upstream Stimulatory Factor
Hepatic lipase promoter activity is reduced by the C-480T and G-216A substitutions present in the common LIPC gene variant, and is increased by Upstream Stimulatory Factor
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DOI：
10.1016/s0021-9150(00)00478-0
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发表时间：
2001-02-15
期刊：
影响因子：
5.3
通讯作者：
Jansen, H
中科院分区：
文献类型：
--
作者：
Botma, GJ;Verhoeven, AJM;Jansen, H
人肝脂肪酶(LIPC)基因启动子区域常见的-216G-->；A和-480C-->；T突变表现出高度的等位基因相关性，并与肝脂酶活性降低和高密度脂蛋白胆固醇水平升高相关。为了测试这些替换的功能，在HepG2细胞中进行了CAT报告分析。LIPC(-650/+48)启动子具有转录活性，而(-650/+61)启动子不具有转录活性。同时含有-216A和-480T的LIPC(-650/+48)的启动子活性显著低于野生型(-45%)。-216G-->；A替换对-289/+48结构的活性没有显著影响。-480C/T位于上游刺激因子(USF)结合区。凝胶位移分析表明，USF蛋白与HL特异性寡核苷酸的结合亲和力因-480C-->；T取代而降低四倍。然而，单独的-480C->；T替换对-650/+48构建体的启动子活性没有显著影响。将USF43基因与HepG2细胞共转染后，ALL-650/+48的活性呈剂量依赖性增加；启动子活性的绝对差异增大，但变异启动子形式之间的相对差异保持不变。我们的研究表明，常见的LIPC启动子变异是功能性的，这解释了-480T等位基因与人类肝脂酶活性较低的关联。(C)2001爱思唯尔爱尔兰科学有限公司。保留所有权利。
The common - 216G --> A and - 480C --> T substitutions in the promoter region of the human hepatic lipase (LIPC) gene show high allelic association, and are correlated with decreased hepatic lipase activity and increased high-density lipoprotein cholesterol levels. To test the functionality of these substitutions, CAT-reporter assays were performed in HepG2 cells. LIPC(-650/ + 48) but not ( - 650/ + 61) promoter constructs showed transcriptional activity. LIPC( - 650/ + 48) constructs with both - 216A and - 480T exhibited significantly lower promoter activity ( - 45%) than the wild-type Form. Activities of - 289/ + 48 constructs were not significantly affected by the -216G --> A substitution. The -480C/T site lies within a binding region for Upstream Stimulatory Factor (USF). Gel-shift assays showed that the binding affinity of USF protein for HL specific oligonucleotides was decreased four-fold by the -480C --> T substitution. However, promoter activity of the -650/ + 48 constructs was not significantly affected by the - 480C --> T substitution alone. Co-transfection of HepG2 cells with USF43 cDNA yielded a similar dose-dependent increase in activity of all - 650/ + 48 constructs; the absolute difference in promoter activity increased but the relative difference between the variant promoter forms was maintained. Our studies demonstrate that the common LIPC promoter variation is functional, which explains the association of the - 480T allele with a lower hepatic lipase activity in man. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.