EBS is a bivalent histone reader that regulates floral phase transition in Arabidopsis

First author: Zhenlin Yang; Affiliations: Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences (中科院上海生命科学研究院): Shanghai, China

Corresponding author: Xuehua Zhong

The ability of cells to perceive and translate versatile cues into differential chromatin and transcriptional states is critical for many biological processes. In plants, timely transition to a flowering state is crucial for successful reproduction. EARLY BOLTING IN SHORT DAY (EBS) is a negative transcriptional regulator that prevents premature flowering (早花) in Arabidopsis thaliana. We found that EBS contains bivalent bromo-adjacent homology (BAH)-plant homeodomain (PHD) reader modules that bind H3K27me3 and H3K4me3, respectively. We observed co-enrichment of a subset of EBS-associated genes with H3K4me3, H3K27me3, and Polycomb repressor complex 2 (PRC2; 多梳抑制复合物). Notably, EBS adopted an autoinhibition mode to mediate its switch in binding preference between H3K27me3 and H3K4me3. This binding balance was critical because disruption (瓦解) of either EBS-H3K27me3 or EBS-H3K4me3 interaction induced early floral transition. Our results identify a bivalent chromatin (二价染色质) reader capable of recognizing two antagonistic histone marks, and we propose a distinct mechanism of interaction between active and repressive chromatin states.

细胞感知信号并翻译成不同染色质和转录状态的能力对于生物的生物学进程是十分重要的。在植物中，适时过渡到开花状态对于植物的生殖是至关重要的。EBS是负转录调控子，防止拟南芥中的提前开花。作者发现EBS包含一个BAH和PHD阅读模块，分别结合H3K27me3和H3K4me3。作者还观察到EBS相关基因H3K4me3，H3K27me3和多梳抑制复合物PRC2的共富集。有趣的是，EBS采用了一种自动抑制模式调控其在与H3K27me3和H3K4me3结合时的优先性。这种结合平衡是非常重要的，因为破坏掉EBS-H3K27me3或者EBS-H3K4me3中任何一个互作都会诱导拟南芥的提早开花。本文的研究鉴定了一个二价染色质阅读器，能够识别两种相互拮抗的组蛋白标记，并且作者提出了一个激活和抑制染色质状态之间互作的分子机制。

p.s. 二价染色质(bivalent chromatin)是指同时存在抑制(H3K27me3)和激活(H3K4me3)的组蛋白标记。

通讯：Xuehua Zhong (https://wid.wisc.edu/people/xuehua-zhong/)

个人简介：武汉大学，学士；俄亥俄州立大学，博士；加利福利亚大学，博士后。

研究方向：植物生长发育的表观调控。

doi: https://doi.org/10.1038/s41588-018-0187-8

Journal: Nature Genetics

First Published:06 August, 2018

（P.S. 原文下载：链接:https://pan.baidu.com/s/1qFiSsqwlF_7JjmGMbedfhQ  密码:dmu6）