...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Molecular and Cellular Biology >Methyl-CpG-Binding Protein MeCP2 Represses Sp1-Activated Transcription of the Human Leukosialin Gene When the Promoter Is Methylated
【24h】

Methyl-CpG-Binding Protein MeCP2 Represses Sp1-Activated Transcription of the Human Leukosialin Gene When the Promoter Is Methylated

机译：甲基-CpG结合蛋白MeCP2抑制启动子被甲基化时人类白细胞基因的Sp1激活转录。

获取原文
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Human leukosialin (CD43) is expressed in a cell lineage-specific as well as a differentiation stage-specific fashion. The leukosialin promoter, made up of an Sp1 binding site and a sequence similar to that of an initiator, possesses high transcriptional potential. Previous data have demonstrated that the leukosialin gene is down-regulated in nonproducing cells by DNA methylation. In this paper the repressive mechanism of DNA methylation in expression systems is reported. In vitro DNA methylation with SssI (CpG) methylase of leukosialin-chloramphenicol acetyltransferase (CAT) constructs drastically reduced transcriptional activities in stable transfection systems with the human HeLa and Jurkat cell lines. On the other hand, the transcriptional repression by in vitro methylation was less pronounced in Drosophila melanogaster cells, which lack genomic methylation. In these cells, Sp1 could transactivate equally well both the unmethylated and methylated leukosialin promoter. In order to test whether one of the methyl-CpG-binding proteins, MeCP2, is responsible for transcriptional repression of the leukosialin gene, I isolated the human MeCP2 cDNA (encoding 486 amino acid residues) and expressed it in Drosophila cells. I found that MeCP2 substantially inhibited Sp1-activated transcription when the leukosialin promoter was methylated. The level of repression was directly proportional to the amount of MeCP2 expression vector transfected. Analysis of C-terminal deletion mutants of MeCP2 showed that repressive activity of Sp1 transactivation is localized to the N-terminal region consisting of amino acid residues 1 to 193, which encompass the methyl-binding domain. These results suggest that interference with Sp1 transactivation by MeCP2 is an important factor in the down-regulation of leukosialin gene expression by DNA methylation.
机译：人白细胞sialin（CD43）以细胞谱系特异性以及分化阶段特异性方式表达。由Sp1结合位点和与启动子相似的序列组成的白细胞增强素启动子具有很高的转录潜能。先前的数据表明白细胞生成素基因在非生产性细胞中通过DNA甲基化被下调。本文报道了表达系统中DNA甲基化的抑制机制。用白细胞唾液酸-氯霉素乙酰转移酶（CAT）的 Sss I（CpG）甲基化酶进行体外DNA甲基化，可在人HeLa和Jurkat细胞系稳定转染系统中大幅降低转录活性。另一方面，果蝇缺乏基因组甲基化的果蝇细胞中，体外甲基化引起的转录抑制作用较弱。在这些细胞中，Sp1可以同样好地激活未甲基化和甲基化的白细胞增强素启动子。为了测试甲基CpG结合蛋白之一MeCP2是否负责白细胞抑制素基因的转录抑制，我分离了人MeCP2 cDNA（编码486个氨基酸残基），并在果蝇中表达了它们。 em>细胞。我发现当白细胞抑制素启动子被甲基化时，MeCP2基本上抑制了Sp1激活的转录。抑制水平与转染的MeCP2表达载体的量成正比。 MeCP2的C端缺失突变体的分析表明，Sp1反式激活的抑制活性位于由氨基酸残基1至193组成的N端区域，该残基包含甲基结合域。这些结果表明，MeCP2对Sp1反式激活的干扰是DNA甲基化下调白细胞介素基因表达的重要因素。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号