Feng Jing, Chen Donghong, Berr Alexandre, Shen Wen-Hui
Institut de Biologie Moléculaire des Plantes, Unité Propre de Recherche 2357 Centre National de la Recherche Scientifique, Université de Strasbourg, 67084 Strasbourg cedex, France (J.F., D.C., A.B., W.-H.S.); and.
Hunan Provincial Key Laboratory of Crop Germplasm Innovation and Utilization, College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha 410128, China (D.C.).
Plant Physiol. 2016 Nov;172(3):1746-1759. doi: 10.1104/pp.16.00193. Epub 2016 Sep 14.
Histone H2A monoubiquitination (H2Aub1), catalyzed by Polycomb-Repressive Complex1 (PRC1), is a key epigenetic mark in Polycomb silencing. However, little is known about how H2Aub1 is read to exert downstream physiological functions. The animal ZUOTIN-RELATED FACTOR1 (ZRF1) has been reported to bind H2Aub1 to promote or repress the expression of varied target genes. Here, we show that the Arabidopsis (Arabidopsis thaliana) ZRF1 homologs, AtZRF1a and AtZRF1b, are key regulators of multiple processes during plant growth and development. Loss of function of both AtZRF1a and AtZRF1b in atzrf1a atzrf1b mutants causes seed germination delay, small plant size, abnormal meristem activity, abnormal flower development, as well as gametophyte transmission and embryogenesis defects. Some of these defects overlap with those described previously in the PRC1-defective mutants atbmi1a atbmi1b and atring1a atring1b, but others are specific to atzrf1a atzrf1b In line with this, 4,519 genes (representing more than 14% of all genes) within the Arabidopsis genome are found differentially expressed in atzrf1a atzrf1b seedlings, and among them, 114 genes are commonly up-regulated in atring1a atring1b and atbmi1a atbmi1b Finally, we show that in both atzrf1a atzrf1b and atbmi1a atbmi1b seedlings, the seed developmental genes ABSCISIC ACID INSENSITIVE3, CRUCIFERIN3, and CHOTTO1 are derepressed, in association with the reduced levels of H2Aub1 and histone H3 lysine-27 trimethylation (H3K27me3). Collectively, our results indicate that AtZRF1a/b play both PRC1-related and PRC1-unrelated functions in regulating plant growth and development and that AtZRF1a/b promote H2Aub1 and H3K27me3 deposition in gene suppression. Our work provides novel insight into the mechanisms of function of this family of evolutionarily conserved chromatin regulators.
由多梳抑制复合物1（PRC1）催化的组蛋白H2A单泛素化（H2Aub1）是多梳沉默中的一种关键表观遗传标记。然而，关于H2Aub1如何被解读以发挥下游生理功能，人们了解甚少。据报道，动物的左亭相关因子1（ZRF1）可结合H2Aub1以促进或抑制多种靶基因的表达。在此，我们表明拟南芥（Arabidopsis thaliana）的ZRF1同源物AtZRF1a和AtZRF1b是植物生长和发育过程中多个进程的关键调节因子。atzrf1a atzrf1b突变体中AtZRF1a和AtZRF1b的功能丧失导致种子萌发延迟、植株矮小、分生组织活性异常、花发育异常以及配子体传递和胚胎发生缺陷。其中一些缺陷与之前在PRC1缺陷突变体atbmi1a atbmi1b和atring1a atring1b中描述的缺陷重叠，但其他缺陷则是atzrf1a atzrf1b特有的。与此一致的是，在拟南芥基因组中发现有4519个基因（占所有基因的14%以上）在atzrf1a atzrf1b幼苗中差异表达，其中有114个基因在atring1a atring1b和atbmi1a atbmi1b中共同上调。最后，我们表明在atzrf1a atzrf1b和atbmi1a atbmi1b幼苗中，种子发育基因脱落酸不敏感3、十字花科蛋白3和CHOTTO1均被去抑制，这与H2Aub1和组蛋白H3赖氨酸-27三甲基化（H3K27me3）水平降低有关。总体而言，我们的结果表明AtZRF1a/b在调节植物生长和发育过程中发挥与PRC1相关和不相关的功能，并且AtZRF1a/b在基因抑制中促进H2Aub1和H3K27me3沉积。我们的工作为这一进化保守的染色质调节因子家族的功能机制提供了新的见解。
