Anhui Provincial Key Laboratory of the Conservation and Exploitation of Biological Resources, Anhui Normal University, Wuhu, 241000, China.
BMC Genomics. 2019 Apr 1;20(1):256. doi: 10.1186/s12864-019-5633-1.
Histone methylation mainly occurs on the lysine residues and plays a crucial role during flowering and stress responses of plants, through changing the methylation status or ratio of lysine residues. Histone lysine residues of plants can arise in three forms of methylation (single, double and triple) and the corresponding demethylation can also ensue on certain occasions, by which the plants can accommodate the homeostasis of histone methylation by means of lysine methyltransferase and demethylase. The JmjC domain-containing proteins, an important family of histone lysine demethylases, play a vital role in maintaining homeostasis of histone methylation in vivo.
In this study, we have identified 19 JmjC domain-containing histone demethylase (JHDM) proteins in maize. Based on structural characteristics and a comparison of phylogenetic relationships of JHDM gene families from Arabidopsis, rice and maize, all 19 JHDM proteins in maize were categorized into three different subfamilies. Furthermore, chromosome location and schematic structure revealed an unevenly distribution on chromosomes and structure features of ZmJMJ genes in maize, respectively. Eventually, the 19 ZmJMJ genes displayed different expression patterns at diverse developmental stages of maize based on transcriptome analysis. Further, quantitative real-time PCR analysis showed that all 19 ZmJMJ genes were responsive to heat stress treatment, suggesting their potential roles in heat stress response.
Overall, our study will serve to present an important theoretical basis for future functional verification of JHDM genes to further unravel the mechanisms of epigenetic regulation in plants.
组蛋白甲基化主要发生在赖氨酸残基上，在植物的开花和应激反应中起着至关重要的作用，通过改变赖氨酸残基的甲基化状态或比例。植物的组蛋白赖氨酸残基可以以三种形式（单、双和三）甲基化，并且在某些情况下也可以发生相应的去甲基化，通过这种方式，植物可以通过赖氨酸甲基转移酶和去甲基酶来适应组蛋白甲基化的内稳态。JmjC 结构域蛋白是组蛋白赖氨酸去甲基酶的一个重要家族，在体内维持组蛋白甲基化的内稳态中起着至关重要的作用。
在这项研究中，我们在玉米中鉴定了 19 个含有 JmjC 结构域的组蛋白去甲基酶（JHDM）蛋白。根据结构特征和拟南芥、水稻和玉米 JHDM 基因家族的系统发育关系比较，玉米中的所有 19 个 JHDM 蛋白被分为三个不同的亚家族。此外，染色体定位和示意结构分别揭示了玉米中 ZmJMJ 基因在染色体上的不均匀分布和结构特征。最终，基于转录组分析，19 个 ZmJMJ 基因在玉米不同发育阶段表现出不同的表达模式。进一步的定量实时 PCR 分析表明，所有 19 个 ZmJMJ 基因都对热应激处理有反应，表明它们在热应激反应中可能具有潜在的作用。
总的来说，我们的研究将为进一步揭示植物表观遗传调控机制提供重要的理论基础，为未来 JHDM 基因的功能验证提供参考。
