Methyl-CpG-Binding Domain Protein MBD7 Is Required for Active DNA Demethylation in Arabidopsis
Methyl-CpG-Binding Domain Protein MBD7 Is Required for Active DNA Demethylation in Arabidopsis
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拟南芥中甲基 CpG 结合域蛋白 MBD7 是活性 DNA 去甲基化所必需的
DOI：
10.1104/pp.114.252106
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发表时间：
2015-03-01
期刊：
影响因子：
7.4
通讯作者：
Gong, Zhizhong
中科院分区：
文献类型：
--
作者：
Wang, Chunlei;Dong, Xiaomei;Gong, Zhizhong
虽然研究人员已经确定DNA甲基化和主动去甲基化在植物细胞中是动态调节的，但调节主动DNA去甲基化的分子机制还不清楚。通过使用表达响应于脱水的启动子29 A：LUCIFERASE（ProRD 29 A：LUC）和启动子花椰菜花叶病毒35 S：新霉素磷酸转移酶II（Pro35 S：NPTII）转基因的拟南芥（Arabidopsis thaliana）系，我们分离了mbd 7（甲基CpG结合结构域蛋白7）突变体。mbd 7突变导致Pro35 S：NPTII转基因失活，但不影响ProRD 29 A：LUC转基因的表达。Pro35 S：NPTII报告基因的沉默与报告基因的DNA超甲基化相关。MBD 7与沉默抑制剂5/DNA甲基化增加2（一种小热休克蛋白家族中的蛋白质）发生物理相互作用。MBD 7更倾向于靶向染色体中心周围具有高密度DNA甲基化的基因组位点。在所有转座子中，主要分布在染色体中心周围的Gypsy型长末端重复反转录转座子受mbd 7的影响最大。我们的研究结果表明，MBD 7是所需的主动DNA去甲基化和抗沉默的基因组位点与高密度的DNA甲基化拟南芥。
Although researchers have established that DNA methylation and active demethylation are dynamically regulated in plant cells, the molecular mechanism for the regulation of active DNA demethylation is not well understood. By using an Arabidopsis (Arabidopsis thaliana) line expressing the Promoter RESPONSIVE TO DEHYDRATION 29A:LUCIFERASE (ProRD29A:LUC) and Promoter cauliflower mosaic virus 35S:NEOMYCIN PHOSPHOTRANSFERASE II (Pro35S:NPTII) transgenes, we isolated an mbd7 (for methyl-CpG-binding domain protein7) mutant. The mbd7 mutation causes an inactivation of the Pro35S:NPTII transgene but does not affect the expression of the ProRD29A:LUC transgene. The silencing of the Pro35S:NPTII reporter gene is associated with DNA hypermethylation of the reporter gene. MBD7 interacts physically with REPRESSOR OF SILENCING5/INCREASED DNAMETHYLATION2, a protein in the small heat shock protein family. MBD7 prefers to target the genomic loci with high densities of DNA methylation around chromocenters. The Gypsy-type long terminal repeat retrotransposons mainly distributed around chromocenters are most affected by mbd7 in all transposons. Our results suggest that MBD7 is required for active DNA demethylation and antisilencing of the genomic loci with high densities of DNA methylation in Arabidopsis.