CAS Center for Excellence in Molecular Plant Sciences, School of Life Sciences, University of Science and Technology of China, Hefei 230027, China.
CAS Center for Excellence in Molecular Plant Sciences, School of Life Sciences, University of Science and Technology of China, Hefei 230027, China
Plant Cell. 2017 Sep;29(9):2197-2213. doi: 10.1105/tpc.17.00266. Epub 2017 Aug 8.
Phosphorylation of histone H3 affects transcription, chromatin condensation, and chromosome segregation. However, the role of phosphorylation of histone H2A remains unclear. Here, we found that MUT9P-LIKE-KINASE (MLK4) phosphorylates histone H2A on serine 95, a plant-specific modification in the histone core domain. Mutations in caused late flowering under long-day conditions but no notable phenotype under short days. MLK4 interacts with CIRCADIAN CLOCK ASSOCIATED1 (CCA1), which allows MLK4 to bind to the () promoter. CCA1 interacts with YAF9a, a co-subunit of the Swi2/Snf2-related ATPase (SWR1) and NuA4 complexes, which are responsible for incorporating the histone variant H2A.Z into chromatin and histone H4 acetylase activity, respectively. Importantly, loss of function led to delayed flowering by decreasing phosphorylation of H2A serine 95, along with attenuated accumulation of H2A.Z and the acetylation of H4 at , thus reducing expression. Together, our results provide insight into how phosphorylation of H2A serine 95 promotes flowering time and suggest that phosphorylation of H2A serine 95 modulated by MLK4 is required for the regulation of flowering time and is involved in deposition of the histone variant H2A.Z and H4 acetylation in Arabidopsis.
组蛋白 H3 的磷酸化会影响转录、染色质凝聚和染色体分离。然而，组蛋白 H2A 的磷酸化作用尚不清楚。在这里，我们发现 MUT9P-LIKE-KINASE（MLK4）在组蛋白核心结构域中的丝氨酸 95 上对组蛋白 H2A 进行磷酸化修饰，这是一种植物特有的修饰。突变导致长日照条件下开花时间延迟，但短日照条件下没有明显表型。MLK4 与 CIRCADIAN CLOCK ASSOCIATED1（CCA1）相互作用，使 MLK4 能够结合到（）启动子上。CCA1 与 YAF9a 相互作用，YAF9a 是 Swi2/Snf2 相关 ATP 酶（SWR1）和 NuA4 复合物的一个共同亚基，它们分别负责将组蛋白变体 H2A.Z 纳入染色质和组蛋白 H4 的乙酰化。重要的是，缺失功能会通过降低组蛋白 H2A 丝氨酸 95 的磷酸化，以及减弱 H2A.Z 的积累和 H4 在 的乙酰化，从而降低的表达，导致开花时间延迟。综上所述，我们的研究结果为组蛋白 H2A 丝氨酸 95 的磷酸化如何促进开花时间提供了深入的了解，并表明由 MLK4 调节的组蛋白 H2A 丝氨酸 95 的磷酸化对于调节开花时间以及涉及组蛋白变体 H2A.Z 和 H4 乙酰化在拟南芥中的沉积是必需的。
