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Marie Mirouze¹, Jon Reinders, Etienne Bucher

¹Department of Plant Biology, University of Geneva, Sciences III, 30 Quai Ernest-Ansermet, CH-1211 Geneva 4, Switzerland.

|September 8, 2009

概括

移动遗传元素称为逆转移体,在植物中是经由表观遗传控制的. 即使在DNA甲基化失败时,RNA聚合酶IV/V和基因素甲基转移酶KYP也会阻止逆转移素的运动,从而保护基因组.

科学领域:

表观遗传学和基因组学
植物分子生物学植物分子生物学
移动遗传元素移动遗传元素

背景情况:

植物和哺乳动物的DNA甲基化使逆转移子沉默,而甲基转移酶1 (MET1) 在Arabidopsis.
在Arabidopsis met1突变体中,逆转移子在转录方面是活跃的,但没有被调动,这表明了转录后沉默机制.

研究的目的:

为了研究控制Arabidopsis中逆转录素调动的后转录机制.
为了确定特定的表观遗传因素,抑制超越转录沉默的逆转移体活性.

主要方法:

混合表观基因组的生成,结合了met1-突变和野生类型的阿拉比多普西斯染色体.
通过观察到由再插入引起的发育突变来识别活跃的逆转移体.
基因组重新排序以检测逆转移子调动.
对参与逆转移素抑制的宿主因素的遗传分析.

主要成果:

观察到一种拷贝类型的逆转移子,Evadé (EVD),可以在混合表观基因组中调动并引起突变.
转录抑制EVD涉及CG甲基化和RNA指导的DNA甲基化.
转录后抑制EVD依赖于植物特异性RNA聚合酶IV/V和基因甲基转移酶KYPTONITE (KYP).
当这些表观遗传机制受损时,专门检测到EBD的逆转换,而不是其他元素.

结论:

在Arabidopsis中,对逆转移体的表观遗传控制超出了转录沉默的范围.
像Evadé这样的特定逆转移子受到独特的多层次表观遗传调节.
RNA聚合酶IV/V和KYP在转录激活后防止逆转录素调动方面发挥着至关重要的作用.

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