Arabidopsis YAF9 histone readers modulate flowering time through NuA4‐complex‐dependent H4 and H2A.Z histone acetylation at FLC chromatin

First author: Pedro Crevillén; Affiliations: Universidad Politécnica de Madrid (马德里理工大学): Pozuelo de Alarcón, Spain

Corresponding author: José A. Jarillo

Posttranslational histone modifications and the dynamics of histone variant H2A.Z are key mechanisms underlying the floral transition. In yeast, SWR1‐C and NuA4‐C mediate the deposition of H2A.Z and the acetylation of histone H4, H2A and H2A.Z, respectively. Yaf9 is a subunit shared by both chromatin‐ emodeling complexes. The significance of the two Arabidopsis YAF9 homologues, YAF9A and YAF9B, is unknown. To get an insight into the role of Arabidopsis YAF9 proteins in plant developmental responses, we followed physiological, genetic, genomic, epigenetic, proteomics and cell biology approaches. Our data revealed that YAF9A and YAF9B are histone H3 readers with unequally redundant functions. Double mutant yaf9a yaf9b plants display pleiotropic developmental phenotypic alterations as well as misregulation of a wide variety of genes. We demonstrated that YAF9 proteins regulate flowering time by both FLC‐dependent and independent mechanisms that work in parallel with SWR1‐C. Interestingly, we show that YAF9A binds FLC chromatin and that YAF9 proteins regulate FLC expression by modulating the acetylation levels of H2A.Z and H4 but not H2A.Z deposition. Our work highlights the key role exerted by YAF9 homologues in the posttranslational modification of canonical histones and variants that regulate gene expression in plants to control development.

翻译后的组蛋白修饰和组蛋白变体H2A.Z的动态变化是植物成花转变的关键机制。在酵母中，SWR1‐C和NuA4‐C介导H2A.Z的沉积以及组蛋白H4、H2A和H2A.Z的乙酰化。Yaf9是两个染色质重塑复合物共同享有的一个亚基。拟南芥的两个YAF9同源物YAF9A和YAF9B的功能还不清楚。为了研究YAF9蛋白在拟南芥生长发育中的作用，作者采用了生理、遗传、基因组学、表观组学、蛋白组学以及细胞生物学的方法。本文的研究显示YAF9A和YAF9B是组蛋白H3的识别蛋白，并且二者之间功能存在冗余，但重要性不一样。yaf9a yaf9b双突的植株表现出多向性的的发育表型改变，同时引起了广泛的基因表达错误调控。作者揭示了YAF9蛋白通过依赖于FLC和独立于FLC的机制与SWR1‐C平行发挥作用，调控植物的开花时间。有趣的是，作者的研究显示YAF9A能够结合FLC染色质，YAF9蛋白通过改变H2A.Z和H4的乙酰化水平来调控FLC的表达，而不是通过H2A.Z的沉积。本文的研究揭示了YAF9同源物通过对组蛋白及组蛋白变体翻译后的修饰调控相关基因的表达，从而影响植物的发育进程。

通讯：José A. Jarillo (http://www.cbgp.upm.es/index.php/es/informacion-cientifica/desarrollo-de-plantas/phase-transitions)

研究方向：调控植物发育状态转变的分子机制。

doi: https://doi.org/10.1111/nph.15737

Journal: New Phytologist

Published online: March 13, 2019