Histone H1 affects gene imprinting and DNA methylation in Arabidopsis.
Histone H1 affects gene imprinting and DNA methylation in Arabidopsis.
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DOI：
10.1111/j.1365-313x.2012.05028.x
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发表时间：
2012-09
期刊：
影响因子：
--
通讯作者：
Xiao W
中科院分区：
文献类型：
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作者：
Rea M;Zheng W;Chen M;Braud C;Bhangu D;Rognan TN;Xiao W
印迹是等位基因的亲本源表达，在哺乳动物和植物的发育调控中起着重要作用。DNA甲基转移酶催化的DNA甲基化通过沉默亲本等位基因在调控印迹中起关键作用。DEMETER （DME）是一种参与碱基切除DNA修复途径的DNA糖基化酶，可从拟南芥DNA中切除5-甲基胞嘧啶并调节基因组印迹。DME使母体MEDEA （MEA）启动子在胚乳中去甲基化，从而导致母体MEA等位基因表达。然而，二甲醚是否与其他蛋白相互作用调控基因印迹尚不清楚。在这里，我们报告了在酵母双杂交筛选中鉴定出组蛋白H1.2作为dme相互作用蛋白，并通过体外拉下实验证实了它们的相互作用。对功能缺失组蛋白h1突变体的遗传分析表明，DME调控拟南芥胚乳MEA、FWA和FIS2印迹需要母体组蛋白h1等位基因，而父本等位基因则是多余的。此外，我们发现组蛋白H1突变导致母体胚乳MEA和FWA启动子DNA甲基化增加。我们的研究结果表明组蛋白H1参与了dme介导的DNA甲基化和印迹位点的基因调控。
Imprinting, parent-of-origin expression of alleles, plays an important role in regulating development in mammals and plants. DNA methylation catalyzed by DNA methyltransferases plays a pivotal role in regulating imprinting by silencing parental alleles. DEMETER (DME), a DNA glycosylase functioning in the base-excision DNA repair pathway, can excise 5-methylcytosine from DNA and regulate genomic imprinting in Arabidopsis. DME demethylates the maternal MEDEA (MEA) promoter in endosperm, thus resulting in expression of the maternal MEA allele. However, it is not known whether DME interacts with other proteins in regulating gene imprinting. Here we report the identification of histone H1.2 as a DME-interacting protein in a yeast two-hybrid screen and confirmation of their interaction by the in vitro pull-down assay. Genetic analysis of the loss-of-function histone h1 mutant shows that the maternal histone H1 allele is required for DME regulation of the MEA, FWA, and FIS2 imprinting in Arabidopsis endosperm while the paternal allele is dispensable. Furthermore, we show that mutations in histone H1 result in an increase of DNA methylation in the maternal MEA and FWA promoter in endosperm. Our results suggest that histone H1 is involved in the DME-mediated DNA methylation and gene regulation at imprinted loci.