Distinct DNA methylation patterns associated with active and inactive centromeres of the maize B chromosome
Distinct DNA methylation patterns associated with active and inactive centromeres of the maize B chromosome
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DOI：
10.1101/gr.116202.110
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发表时间：
2011-06-01
期刊：
影响因子：
7
通讯作者：
Jiang, Jiming
中科院分区：
文献类型：
--
作者：
Koo, Dal-Hoe;Han, Fangpu;Jiang, Jiming
着丝粒由知之甚少的表观遗传机制决定。着丝粒可以被激活或失活而不改变潜在的DNA序列。然而，几乎没有什么是已知的表观遗传过渡的着丝粒从一个积极的非活动状态，因为缺乏的例子，相同的着丝粒表现出替代形式，并从其他着丝粒区分。玉米额外B染色体的着丝粒提供了这样的机会，因为其功能核心可以在细胞学上追踪，并且可以获得着丝粒的无活性版本。我们开发了一种基于DNA纤维的技术，可用于评估与重复DNA序列相关的胞嘧啶甲基化水平。我们报告，DNA序列在正常的B着丝粒表现出低甲基化。这种甲基化模式不受B染色体的遗传背景或结构重排的影响，但当B染色体作为附加染色体转移到燕麦中时，甲基化模式略有改变。相反，同一着丝粒的非活性版本表现出超甲基化，表明非活性着丝粒在DNA水平上被修饰成不同的表观遗传状态。
Centromeres are determined by poorly understood epigenetic mechanisms. Centromeres can be activated or inactivated without changing the underlying DNA sequences. However, virtually nothing is known about the epigenetic transition of a centromere from an active to an inactive state because of the lack of examples of the same centromere exhibiting alternative forms and being distinguishable from other centromeres. The centromere of the supernumerary B chromosome of maize provides such an opportunity because its functional core can be cytologically tracked, and an inactive version of the centromere is available. We developed a DNA fiber-based technique that can be used to assess the levels of cytosine methylation associated with repetitive DNA sequences. We report that DNA sequences in the normal B centromere exhibit hypomethylation. This methylation pattern is not affected by the genetic background or structural rearrangement of the B chromosome, but is slightly changed when the B chromosome is transferred to oat as an addition chromosome. In contrast, an inactive version of this same centromere exhibits hypermethylation, indicating that the inactive centromere was modified into a different epigenetic state at the DNA level.