Arabidopsis cmt3 chromomethylase mutations block non-CG methylation and silencing of an endogenous gene
Arabidopsis cmt3 chromomethylase mutations block non-CG methylation and silencing of an endogenous gene
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DOI：
10.1101/gad.905701
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发表时间：
2001-07-15
影响因子：
10.5
通讯作者：
Bender, J
中科院分区：
文献类型：
--
作者：
Bartee, L;Malagnac, F;Bender, J
植物在CG和非CG残基上维持胞嘧啶甲基化，以控制基因表达和基因组稳定性。在对改变一个高度甲基化的内源报告基因的甲基化和沉默的拟南芥突变体的筛选中，我们获得了CMT3染色质甲基化酶基因的11个功能丧失等位基因。cmt3突变体显示报告基因的表达增强且甲基化降低，特别是在非CC胞嘧啶处。在重复的着丝粒序列中，CNG甲基化也降低了。因此，CMT3是非CC甲基化的关键决定因素。动物基因组中缺乏CMT同源物可以解释这样一个观察结果：与植物相反，动物主要维持CG甲基化。
Plants maintain cytosine methylation at CG and non-CG residues to control gene expression and genome stability. In a screen for Arabidopsis mutants that alter methylation and silencing of a densely methylated endogenous reporter gene, we recovered 11 loss-of-function alleles in the CMT3 chromomethylase gene. The cmt3 mutants displayed enhanced expression and reduced methylation of the reporter, particularly at non-CC cytosines. CNG methylation was also reduced at repetitive centromeric sequences. Thus, CMT3 is a key determinant for non-CC methylation. The lack of CMT homologs in animal genomes could account for the observation that in contrast to plants, animals maintain primarily CG methylation.