Methylation of CpG dinucleotides alters binding and silences testis-specific transcription directed by the mouse lactate dehydrogenase C promoter
Methylation of CpG dinucleotides alters binding and silences testis-specific transcription directed by the mouse lactate dehydrogenase C promoter
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DOI：
10.1095/biolreprod65.5.1522
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发表时间：
2001-11-01
影响因子：
3.6
通讯作者：
Goldberg, E
中科院分区：
文献类型：
--
作者：
Kroft, TL;Jethanandani, P;Goldberg, E
小鼠乳酸脱氢酶c基因（mldhc）仅在生殖上皮细胞中转录。mldhc启动子的克隆和分析显示，一个100碱基对的片段能够在体外和转基因小鼠中驱动睾丸特异性转录。一些睾丸特异性基因被认为至少部分通过CpG二核苷酸的差异甲基化来调节。我们研究了mldhc基因的转录抑制在体细胞组织中由CpG二核苷酸的超甲基化介导的可能性。mldhc启动子片段内的CpG二核苷酸含有GC盒和串联激活转录因子/cAMP反应元件结合位点，在体细胞组织中高甲基化，在睾丸中低甲基化。激活转录因子/cAMP反应元件的甲基化改变了在使用小鼠肝脏但不是睾丸核提取物的电泳迁移率变动分析中观察到的蛋白质结合模式。此外，在瞬时转染测定中，驱动lac Z的延伸的mldhc启动子片段的甲基化使启动子的转录沉默。这些数据表明，组织特异性差异甲基化在体细胞组织中的mldhc沉默中起作用。
The mouse lactate dehydrogenase c gene (mldhc) is transcribed only in cells of the germinal epithelium. Cloning and analysis of the mldhc promoter revealed that a 100-base pair fragment was able to drive testis-specific transcription in vitro and in transgenic mice. Several testis-specific genes are believed to be regulated at least in part through differential methylation of CpG dinucleotides. We investigated the possibility that transcriptional repression of the mldhc gene is mediated in somatic tissues by hypermethylation of CpG dinucleotides. The CpG dinucleotides within a fragment of the mldhc promoter containing a GC box and tandem activating transcription factor/cAMP-responsive element binding sites are hypermethylated in somatic tissues and hypomethylated in testis. Methylation of the activating transcription factor/cAMP-responsive elements altered the protein binding pattern observed in electrophoretic mobility shift assays using mouse liver but not testis nuclear extract. Furthermore, methylation of an extended mldhc promoter fragment driving lac Z silenced transcription from the promoter in a transient transfection assay. These data suggest that tissue-specific differential methylation plays a role in mldhc silencing in somatic tissues.