The investigation of the histone proteins acetylation and the DNA methylation in monozygotic twins discordant for schizophrenia

我们试图研究精神分裂症与表观遗传事件之间的关系，如DNA甲基化和组蛋白乙酰化。首先，我们使用甲基化敏感限制性内切酶Hap II和甲基化不敏感酶MspI检测了多巴胺D2受体基因（DRD2）的启动子区域是否被甲基化。研究对象为5对患有精神分裂症的同卵双胞胎（均为男性，平均年龄42.6岁，患病时间均在10年以上）。用苯酚法从淋巴细胞中提取基因组DNA样本。酶切后进行聚合酶链反应（PCR），用聚丙烯酰胺凝胶电泳测定PCR产物的大小。在五对双胞胎中，有四对双胞胎的DRD2启动子区域甲基化水平高于正常双胞胎。在一对中，两者的水平几乎相等。本研究为精神分裂症异卵双胞胎的表型差异与DNA甲基化之间的关系提供了一些证据。因此，在未来的研究中，我们将尝试收集更多的受试者并使用其他酶。接下来，我们对精神分裂症不一致的同卵双胞胎进行snp基因分型和基因表达分析，并在双胞胎之间进行比较。研究对象为一对同卵男性双胞胎（年龄51岁），其中一人患有DSM-IV型精神分裂症，未分化型，另一人有工作，已婚，适应社会生活。这些样本是来自受试者的基因组DNA和RNA。使用Affymetrix基因芯片Human Mapping 100K Set （50K Xba Array, 50K Hind Array）分型，使用Affymetrix Human Genome U133 Plus 2.0 Array分析基因表达。在单核苷酸多态性基因分型中，有46个单核苷酸多态性在双胞胎之间的116204个单核苷酸多态性中具有不同的信号强度。同时，我们检测了12857个基因的表达水平。结果，我们检测到4个信号强度不同的SNPs，它们位于双胞胎之间基因表达不同的基因的5'端或内含子附近。通过测序，我们证实这些区域的DNA序列没有改变。因此，可以认为是一些表观遗传事件导致了基因表达的改变。我们将研究包括这些snp在内的基因与精神分裂症之间的关系。少

We tried to investigate the relationship between schizophrenia and the epigenetic events such as the methylation of DNA and the acetylation of histone proteins. First, we examined whether the promoter region of dopamine D2 receptor gene (DRD2) was methylated, using the methylation-sensitive restriction enzyme, Hap II, and the methylation-insensitive enzyme, MspI. The subjects were five pairs of monozygotic twins discordant for DSM-IV schizophrenia (all pairs were male, mean age 42.6 years; all twins had been discordant more than ten years). The genome DNA samples were extracted from lymphocytes by the phenol method. After enzyme digestion, polymerase chain reaction (PCR) was performed, and the size of PCR products was determined using polyacrylamide gel electrophoresis. In four out of five pairs, the level of methylation of the DRD2 promoter region was higher in the affected twin than the normal twin. In one pair, the level was nearly equal in both. In this study, we found some evidenc … More e for the relationship between phenotypic difference in monozygotic twins discordant for schizophrenia and DNA methylation. Therefore in future studies we will try to collect more subjects and use other enzymes.Next, we performed SNPs genotyping and gene expression analysis in monozygotic twins discordant for schizophrenia and compared between twins. The subjects were a pair of monozygotic male twins (age:51), one had DSM-IV schizophrenia, undifferentiated type, and the other had a job, was married, and was well-adapted to social life. The samples were genomic DNA and RNA from the subjects. The SNPs were typed using Affymetrix GeneChip Human Mapping 100K Set (50K Xba Array, 50K Hind Array) and the gene expressions were analyzed by Affymetrix Human Genome U133 Plus 2.0 Array. In SNPs genotyping, forty six SNPs had different signal intensity among all 116204 SNPs between twins. Also, we measured the expression level of 12857 genes. As a results, we detected 4 SNPs that had different signal intensity and located near the 5' end or intron of the genes that showed the different gene expression between twins. By sequencing, we confirmed that there were no alterations of DNA sequences in these regions. Therefore, it could be thought that some epigenetic events caused the change of gene expression. We will investigate the associations between the genes including these SNPs and schizophrenia. Less