Methylation pattern of activator transposase binding sites in maize endosperm
Methylation pattern of activator transposase binding sites in maize endosperm
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DOI：
10.1105/tpc.8.4.747
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发表时间：
1996-04-01
期刊：
影响因子：
11.6
通讯作者：
Kunze, R
中科院分区：
文献类型：
--
作者：
Wang, LH;Heinlein, M;Kunze, R
玉米转座因子激活因子（Ac）仅从两个子染色单体中的一个复制后转座。有研究表明，DNA甲基化与甲基化敏感转座酶结合可能控制Ac转座和复制的关联。我们对wx-m9::Ac等位基因Ac两端转座酶结合位点的胞嘧啶甲基化模式进行了详细的基因组测序分析，其中Ac插入到蜡质基因的第10外显子中。wx-m9::Ac核中的Ac元素表现出有趣的甲基化模式，并分为两个不同的组。大约50%的元素通过5'端（启动子端）的256个核苷酸在胞嘧啶残基上完全未甲基化。另一半在Ac残基27和92之间部分甲基化。相反，在3'端，所有的Ac分子在4372和4554残基之间被严重甲基化。位于内部的Ac序列和侧翼的Waxy DNA未甲基化。尽管Ac中大多数甲基化的胞嘧啶位于对称的CpG和CpNpG排列中，但在Ac的高甲基化区域中，不对称的胞嘧啶甲基化也很常见。这些结果表明，在该模型中，转座子末端的半甲基化差异激活控制了转座子的选择性和与复制的关联。
The maize transposable element Activator (Ac) transposes after replication from only one of the two daughter chromatids. It has been suggested that DNA methylation in conjunction with methylation-sensitive transposase binding to DNA may control the association of Ac transposition and replication. We present hem a detailed genomic sequencing analysis of the cytosine methylation patterns of the transposase binding sites within both Ac ends in the wx-m9::Ac allele, where Ac is inserted into the tenth exon of the Waxy gene. The Ac elements in wx-m9::Ac kernels exhibit intriguing methylation patterns and fall into two distinct groups. Approximately 50% of the elements are fully unmethylated at cytosine residues through the 256 nucleotides at the 5' end (the promoter end). The other half is partially methylated between Ac residues 27 and 92. In contrast, at the 3' end, all Ac molecules are heavily methylated between residues 4372 and 4554. The more internally located Ac sequences and the flanking Waxy DNA are unmethylated. Although most methylated cytosines in Ac are in the symmetrical CpG and CpNpG arrangements, nonsymmetrical cytosine methylation is also common in the hypermethylated regions of Ac. These results suggest a model in which differential activation of transposon ends by hemimethylation controls the chromatid selectivity of transposition and the association with replication.