Relationship between DNA methylation states and transcription of individual isoforms encoded by the protocadherin-α gene cluster
Relationship between DNA methylation states and transcription of individual isoforms encoded by the protocadherin-α gene cluster
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DOI：
10.1074/jbc.m709648200
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发表时间：
2008-05-02
影响因子：
4.8
通讯作者：
Yagi, Takeshi
中科院分区：
文献类型：
--
作者：
Kawaguchi, Masahumi;Toyama, Tomoko;Yagi, Takeshi
原钙粘蛋白-α（Pcdh-α）基因编码在脊椎动物中枢神经系统的单个神经元中差异表达的多种跨膜蛋白。Pcdh-α基因组结构包含可变的第一外显子，每个外显子由其自身的启动子调控。在这里，我们研究了DNA甲基化对Pcdh-α基因簇中基因调控的影响。我们研究了表达不同Pcdh-α亚型组合的两种小鼠细胞系C1300和M3，发现1）特定Pcdh-α亚型的转录与启动子和第一外显子5 '（而不是3'）区域的甲基化状态显著相关，2）启动子的嵌合或混合甲基化状态与活性和非活性转录相关。C1300细胞的去甲基化上调了所有的Pcdh-α亚型，并且在启动子测定中，启动子的超甲基化抑制了它们的转录活性。从去甲基化的C1300细胞亚克隆的细胞系转录不同的组合Pcdh-α亚型比亲本，非去甲基化的细胞，和启动子显示出差异镶嵌或混合甲基化模式。在体内，在所有神经元中转录的Pcdh-α C1和α C2外显子的启动子和5 '-区被广泛低甲基化。相比之下，Pcdh-α 1-α 12亚型的启动子，这是由个人浦肯野细胞差异转录，表现出马赛克甲基化模式。总体而言，我们的研究结果表明，嵌合或混合DNA甲基化状态的启动子和5 '区的第一个外显子可能有助于调节差异Pcdh-α转录和高甲基化是足以抑制转录。
The protocadherin-alpha (Pcdh-alpha) gene encodes diverse transmembrane proteins that are differentially expressed in individual neurons in the vertebrate central nervous system. The Pcdh-alpha genomic structure contains variable first exons, each regulated by its own promoter. Here, we investigated the effect of DNA methylation on gene regulation in the Pcdh-alpha gene cluster. We studied two mouse cell lines, C1300 and M3, that expressed different combinations of Pcdh-alpha isoforms and found that 1) the transcription of specific Pcdh-alpha isoforms correlated significantly with the methylation state of the promoter and the 5' (but not the 3') region of the first exon and 2) mosaic or mixed methylation states of the promoters were associated with both active and inactive transcription. Demethylation of C1300 cells up-regulated all of the Pcdh-alpha isoforms, and, in a promoter assay, hypermethylation of the promoters repressed their transcriptional activity. Cell lines subcloned from the demethylated C1300 cells transcribed different combinations of Pcdh-alpha isoforms than the parental, nondemethylated cells, and the promoters showed differential mosaic or mixed methylation patterns. In vivo, the promoter and 5'-regions of the Pcdh-alpha C1 and alpha C2 exons, which are transcribed in all neurons, were extensively hypomethylated. In contrast, the promoters of the Pcdh-alpha 1 to -alpha 12 isoforms, which are transcribed differentially by individual Purkinje cells, exhibited mosaic methylation patterns. Overall, our results demonstrated that mosaic or mixed DNA methylation states in the promoter and 5'-region of the first exon may help regulate differential Pcdh-alpha transcription and that hypermethylation is sufficient to repress transcription.