DNA Methylation Dynamics during Sexual Reproduction in Arabidopsis thaliana
DNA Methylation Dynamics during Sexual Reproduction in Arabidopsis thaliana
复制标题
DOI：
10.1016/j.cub.2012.07.061
复制
发表时间：
2012-10-09
期刊：
影响因子：
9.2
通讯作者：
Berger, Frederic
中科院分区：
文献类型：
--
作者：
Jullien, Pauline E.;Susaki, Daichi;Berger, Frederic
DNA甲基化维持基因组稳定性并调节基因表达[1]。在哺乳动物中，DNA甲基化在生殖系中从一代到下一代重新编程[2]。在植物中，人们认为DNA甲基化的模式通过有性生殖稳定地维持[3-6]。然而，最近的一份报告显示，从母体到子代植物的DNA甲基化谱存在离散变化[7]。解释这些变化的机制仍然未知。在这里，我们报告说，维持DNA甲基转移酶几乎没有表达在拟南芥雌性配子发生。相反，受精后，维持和从头DNA甲基转移酶在胚胎中强烈表达。胚胎发生的标志是增加从头DNA甲基化，达到进一步维持在成年植物的水平。受精后这些表观遗传标记的积累沉默了甲基化敏感的荧光报告。胚胎中的从头DNA甲基化提供了一种机制，可以解释实验去甲基化基因组的逐渐再甲基化[8，9]。总之，我们发现DNA甲基化活性在有性生殖过程中会波动。这种循环可能解释了拟南芥中DNA甲基化的全基因组模式在世代之间的变化[7，10]，并使表观基因组的重编程程度有限。
DNA methylation maintains genome stability and regulates gene expression [1]. In mammals, DNA methylation is reprogrammed in the germline from one generation to the next [2]. In plants, it was considered that patterns of DNA methylation are stably maintained through sexual reproduction [3-6]. However, a recent report showed discrete variations of DNA methylation profiles from mother to daughter plants [7]. The mechanisms that explain these variations have remained unknown. Here, we report that maintenance DNA methyltransferases are barely expressed during Arabidopsis female gametogenesis. In contrast, after fertilization both maintenance and de novo DNA methyltransferases are expressed strongly in the embryo. Embryogenesis is marked by increased de novo DNA methylation, reaching levels that are further maintained in the adult plant. The accumulation of these epigenetic marks after fertilization silences a methylation-sensitive fluorescent reporter. De novo DNA methylation in the embryo provides a mechanism that could account for the gradual remethylation of experimentally demethylated genomes [8, 9]. In conclusion, we uncover that DNA methylation activity fluctuates during sexual reproduction. This cycle likely explains variations of genome-wide patterns of DNA methylation across generations in Arabidopsis [7, 10] and enables a limited degree of reprogramming of the epigenome.