Arabidopsis MSI1 connects LHP1 to PRC2 complexes
Arabidopsis MSI1 connects LHP1 to PRC2 complexes
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DOI：
10.1038/emboj.2013.145
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发表时间：
2013-07-17
期刊：
影响因子：
11.4
通讯作者：
Hennig, Lars
中科院分区：
文献类型：
--
作者：
Derkacheva, Maria;Steinbach, Yvonne;Hennig, Lars
Polycomb group（PcG）蛋白质在植物和动物的发育过程中形成控制基因表达的基本表观遗传记忆系统。然而，植物PcG蛋白的功能机制仍然知之甚少。本文探讨了植物多梳阻遏复合物2（Polycomb repressive complex 2，PRC 2）的组成和功能。这项工作确立了这样一个事实，即所有已知的植物PRC 2复合物都含有果蝇p55的同源物MSI 1。虽然p55对于PRC 2的体外酶活性不是必需的，但是植物MSI 1对于胚胎花和春化PRC 2复合物的功能是必需的，包括靶染色质处的组蛋白H3 Lys 27（H3 K27）的三甲基化，以及基因阻遏和花的感受态的建立。我们发现MSI 1用于将PRC 2连接到LIKE异染色质蛋白1（LHP 1），LHP 1是一种在体外和体内结合H3 K27 me 3的蛋白，并且是功能性植物PcG系统所需的。LHP 1-MSI 1相互作用形成正反馈环以将PRC 2募集到携带H3 K27 me 3的染色质。因此，这可以提供一种机制，通过复制的地方表观遗传信息的忠实继承。
Polycomb group (PcG) proteins form essential epigenetic memory systems for controlling gene expression during development in plants and animals. However, the mechanism of plant PcG protein functions remains poorly understood. Here, we probed the composition and function of plant Polycomb repressive complex 2 (PRC2). This work established the fact that all known plant PRC2 complexes contain MSI1, a homologue of Drosophila p55. While p55 is not essential for the in vitro enzymatic activity of PRC2, plant MSI1 was required for the functions of the EMBRYONIC FLOWER and the VERNALIZATION PRC2 complexes including trimethylation of histone H3 Lys27 (H3K27) at the target chromatin, as well as gene repression and establishment of competence to flower. We found that MSI1 serves to link PRC2 to LIKE HETEROCHROMATIN PROTEIN 1 (LHP1), a protein that binds H3K27me3 in vitro and in vivo and is required for a functional plant PcG system. The LHP1-MSI1 interaction forms a positive feedback loop to recruit PRC2 to chromatin that carries H3K27me3. Consequently, this can provide a mechanism for the faithful inheritance of local epigenetic information through replication.