| Summary: | 碩士 === 國立陽明大學 === 遺傳學研究所 === 92 === Epigenetic means any heritable change in gene expression that is not caused by change in DNA sequence. As such it is believed to contribute to the gene expression in the cell and the normal processes of human development but also to aberrant disease states such as cancer. DNA methylation , histone modification , position-effect variegation and RNAi etc.. are all in this area. If we enhance understanding of the epigenetic will probably prove helpful diagnosis and treatment of some disease including cancer. Here we want to know the relationship between DNA methylation and histone modification.
DNA methylation and histone modification promoter change chromatin structure that may affect gene expression. In the recent experiments, they reveal the DNA methylation is downstream of the H3 methylation and DNA methylation can be recognized by the MBD, then recruit histone deacetylase complex to change the modification of the histone. They are two links between the sequential events of histone modification and DNA methylation. Here, we search database and find some genes (CLLD8, SETDB1,CG12196 and R05D3.11) containing both methyl CpG-binding domain and pre-SET/SET domain and they may be other link between DNA methylation and histone modification.In this study, we express their methyl CpG-binding domains in the E.coli system ,then testing their function by EMSA ; only the Drosophila gene CG12196 has the interaction. It reveals the Drosophila gene CG12196 may modulate the whole of histone methylation by the DNA methylation but other's gene can not. And we also express their pre-SET/SET domain in the E.coli system , then testing it's activity using histone methyltransferase assay ; but all genes do not have the activity.In the future, we will express their pre-SET/SET domain in the baculoviruses system and try again it have activity or not.
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