Functional analysis of promoter variants in the microsomal triglycerlide transfer protein (MTTP) gene
Functional analysis of promoter variants in the microsomal triglycerlide transfer protein (MTTP) gene
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DOI：
10.1002/humu.20615
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发表时间：
2008-01-01
期刊：
影响因子：
3.9
通讯作者：
Doering, Frank
中科院分区：
文献类型：
--
作者：
Rubin, Diana;Schneider-Muntau, Alexandra;Doering, Frank
微粒体甘油三酯转移蛋白（MTTP）是从肠和肝组装和分泌含载脂蛋白B（apoB）的脂蛋白所必需的。根据这一功能，MTTP基因的多态性位点与低密度脂蛋白（LDL）胆固醇和代谢综合征的相关性状相关。在这里，我们研究了常见的MTTP启动子多态性rs 1800804：T > C（-164 T> C），rs 1800803：A > T（-400 A> T）和rs 1800591：G > T（-493 G> T）的功能影响，在肠道Caco-2和肝Huh，7细胞中使用基因报告分析。在Huh-7细胞中获得显著结果。常见的MTTP启动子单倍型-164 T/-400 A/-493 G的活性比罕见的单倍型-164 C/-400 T/-493 T低约两倍。MTTP启动子突变体构建体-164 T/-400 A/-493 T和-164 T/-400 T/-493 T表现出与常见单倍型相似的活性。突变体-164C/-400A/-493G和-164C/-400A/-493T的活性与罕见的MTTP启动子单元型相似。电泳迁移率变动分析（EMSA）显示转录因子固醇调节元件结合蛋白1a（SREBP 1a）与-164T探针的结合能力高于-164C探针。总之，我们的研究表明，多态性-164 T> C介导的不同活动的共同MTTP启动子单倍型通过SREBP 1a。这表明已经描述的通过饮食对MTTP表达的SREBR依赖性调节在-164T携带者中比在-164C携带者中更有效。
The microsomal triglyceride transfer protein (MTTP) is required for the assembly and secretion of apolipoprotein B (apoB)-containing lipoproteins from the intestine and liver. According to this function, polymorphic sites in the MTTP gene showed associations to low-density lipoprotein (LDL) cholesterol and related traits of the metabolic syndrome. Here we studied the functional impact of common MTTP promoter polymorphisms rs1800804:T > C (-164T > C), rs1800803:A > T (-400A > T), and rs1800591:G > T (-493G > T) using gene-reporter assays in intestinal Caco-2 and liver Huh,7 cells. Significant results were obtained in Huh-7 cells. The common MTTP promoter haplotype -164T/-400A/-493G showed about twofold lower activity than the rare haplotype -164C/-400T/-493T. MTTP promoter mutant constructs -164T/ -400A/-493T and -164T/-400T/-493T exhibited similar activity than the common haplotype. Activities of mutants -164C/-400A/-493G and -164C/-400A/-493T resembled the rare MTTP promoter haplotype. Electrophoretic mobility shift assays (EMSAs) revealed higher binding capacity of the transcriptional factor Sterol regulatory element binding proteinla (SREBP1a) to the -164T probe in comparison to the -164C probe. In conclusion, our study indicates that the polyrnorphism -164T > C mediates different activities of common MTTP promoter haplotypes via SREBP1a. This suggested that the already described SREBR-dependent modulation of MTTP expression by diet is more effective in -164T than in -164C carriers.