Current understanding of plant Polycomb group proteins and the repressive histone H3 Lysine 27 trimethylation.
Current understanding of plant Polycomb group proteins and the repressive histone H3 Lysine 27 trimethylation.
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DOI：
10.1042/bst20200192
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发表时间：
2020-07
影响因子：
3.9
通讯作者：
Huijun Jiao;Yu Xie;Zicong Li
中科院分区：
文献类型：
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作者：
Huijun Jiao;Yu Xie;Zicong Li
Polycomb group（PcG）蛋白是一类高度保守的染色质修饰复合物，在高等真核生物中起着基因沉默的作用。PcG蛋白调控着成千上万的基因和多种发育过程。甲基转移酶卷曲叶（CLF）及其催化的组蛋白H3赖氨酸27三甲基化（H3K27me3）作为第一个在模式植物拟南芥中发现的染色质修饰因子，已成为植物表观遗传学研究的重要范式。与动物一样，PcG蛋白通过拮抗三胸组蛋白介导植物发育并抑制同源异型基因表达。近年来，人们对植物PcG蛋白的研究取得了很大进展，包括PcG蛋白复合物中植物特异性组分的存在、与转录因子和非编码RNA的时空特异性联系、抑制性标记H3K27me3的动态调控以及PcG蛋白介导的染色质构象改变等。本文综述了PcG抑制基因表达的分子机制，并讨论了H3K27me3与另一种抑制基因表达的标志物H2A121ub的关系。
Polycomb group (PcG) proteins are highly conserved chromatin-modifying complexes that implement gene silencing in higher eukaryotes. Thousands of genes and multiple developmental processes are regulated by PcG proteins. As the first chromatin modifier been identified in model plant Arabidopsis thaliana, the methyltransferase CURLY LEAF (CLF) and its catalyzed histone H3 Lysine 27 trimethylation (H3K27me3) have already become well-established paradigm in plant epigenetic study. Like in animals, PcG proteins mediate plant development and repress homeotic gene expression by antagonizing with trithorax group proteins. Recent researches have advanced our understanding on plant PcG proteins, including the plant-specific components of these well-conserved protein complexes, the close association with transcription factors and noncoding RNA for the spatial and temporal specificity, the dynamic regulation of the repressive mark H3K27me3 and the PcG-mediated chromatin conformation alterations in gene expression. In this review, we will summarize the molecular mechanisms of PcG-implemented gene repression and the relationship between H3K27me3 and another repressive mark histone H2A Lysine 121 mono-ubiquitination (H2A121ub) will also be discussed.