载脂蛋白 B(apo B)是引起动脉粥样硬化病的重要危险因子之一,研究apo B基因的结构、功能及其与疾病的关系是极其重要的.从已有的研究结果证明,apo B基因含29个外显子,5’末端3kb的区域内分别含有加强子(Enhancer)、启动子(Promoter)和...载脂蛋白 B(apo B)是引起动脉粥样硬化病的重要危险因子之一,研究apo B基因的结构、功能及其与疾病的关系是极其重要的.从已有的研究结果证明,apo B基因含29个外显子,5’末端3kb的区域内分别含有加强子(Enhancer)、启动子(Promoter)和衰减子(Reducer).不久前发现,apo B基因的3’末端第二个多聚A后面约500～800 bp的片段是一个高可变的重复序列(hyper-variable number of tandem repeats,VNTR),每15个核苷酸为一个重复单位,该序列中富含A和T,把(ATAATTAAATATTTT)命名为X,(ATAATTAAAATATTT)命名为Y,在该片段中若T,A被G,C取代,这样的重复序列被统称为X,Y的变异体,按其取代位置分别命名为Xi,Xii,Xiii,Yi,Yii和Yiii(图1)。展开更多
Objective To study the structure of alleles in the 3' end of the apoB gene in Han, Mongolian and Tibetan populations in China as well as the roles in the regulation of gene expression. Methods DNA were obtained...Objective To study the structure of alleles in the 3' end of the apoB gene in Han, Mongolian and Tibetan populations in China as well as the roles in the regulation of gene expression. Methods DNA were obtained from human leukocytes by phenol chloroform extraction and ethanol precipitation. PCR were carried out in a 50 μl volume containing 50 ng genomic DNA as template. The Ssp1 digested products were loaded on a gradient acrylamide gel and run for 3 hours. The constructs containing alleles were tested in cultured HepG2 and HeLa cells using transient assays. Results Sixteen alleles with different repeat number were characterized. All of the alleles varying from HVE22 to HVE52, allele HVE34 was the most common (58.4%), followed by allele HVE36 (13.8%) and HVE32 (10.5%). 258 PCR products were digested with Ssp1 and run in 4-12% PAGE. We detected the fragments of 266bp, 91bp, 61bp and 39bp in almost all samples. The small alleles (including HVE22, HVE24, HVE26 and HVE36) decreased the expressive activity of the luciferase reporter, in contrary, the large alleles (including HVE44, HVE46 and HVE48) elevated obviously the expressive activity of the luciferase reporter. Conclusions More alleles with different number of tandem repeats in 3' end of apoB gene exist in the Chinese populations. The alleles in 3' end minisatellite of human apoB gene could control the expression of the gene itself.展开更多
文摘载脂蛋白 B(apo B)是引起动脉粥样硬化病的重要危险因子之一,研究apo B基因的结构、功能及其与疾病的关系是极其重要的.从已有的研究结果证明,apo B基因含29个外显子,5’末端3kb的区域内分别含有加强子(Enhancer)、启动子(Promoter)和衰减子(Reducer).不久前发现,apo B基因的3’末端第二个多聚A后面约500～800 bp的片段是一个高可变的重复序列(hyper-variable number of tandem repeats,VNTR),每15个核苷酸为一个重复单位,该序列中富含A和T,把(ATAATTAAATATTTT)命名为X,(ATAATTAAAATATTT)命名为Y,在该片段中若T,A被G,C取代,这样的重复序列被统称为X,Y的变异体,按其取代位置分别命名为Xi,Xii,Xiii,Yi,Yii和Yiii(图1)。
文摘Objective To study the structure of alleles in the 3' end of the apoB gene in Han, Mongolian and Tibetan populations in China as well as the roles in the regulation of gene expression. Methods DNA were obtained from human leukocytes by phenol chloroform extraction and ethanol precipitation. PCR were carried out in a 50 μl volume containing 50 ng genomic DNA as template. The Ssp1 digested products were loaded on a gradient acrylamide gel and run for 3 hours. The constructs containing alleles were tested in cultured HepG2 and HeLa cells using transient assays. Results Sixteen alleles with different repeat number were characterized. All of the alleles varying from HVE22 to HVE52, allele HVE34 was the most common (58.4%), followed by allele HVE36 (13.8%) and HVE32 (10.5%). 258 PCR products were digested with Ssp1 and run in 4-12% PAGE. We detected the fragments of 266bp, 91bp, 61bp and 39bp in almost all samples. The small alleles (including HVE22, HVE24, HVE26 and HVE36) decreased the expressive activity of the luciferase reporter, in contrary, the large alleles (including HVE44, HVE46 and HVE48) elevated obviously the expressive activity of the luciferase reporter. Conclusions More alleles with different number of tandem repeats in 3' end of apoB gene exist in the Chinese populations. The alleles in 3' end minisatellite of human apoB gene could control the expression of the gene itself.
