Abstract：
Plants can sense temperature changes and adjust their development and morphology accordingly in a process called thermomorphogenesis. This phenotypic plasticity implies complex mechanisms regulating gene expression reprogramming in response to environmental alteration. Histone variants often associate with specific chromatin states; yet, how their deposition/eviction modulates transcriptional changes induced by environmental cues remains elusive. In Arabidopsis thaliana, temperature elevation-induced transcriptional activation at thermo-responsive genes entails the chromatin eviction of a histone variant H2A.Z by INO80, which is recruited to these loci via interacting with a key thermomorphogenesis regulator PIF4. Here, we show that both INO80 and the deposition chaperones of another histone variant H3.3 associate with ELF7, a critical component of the transcription elongator PAF1 complex. H3.3 promotes thermomorphogenesis and the high temperature-enhanced RNA Pol II transcription at PIF4 targets, and it is broadly required for the H2A.Z removal-induced gene activation. Reciprocally, INO80 and ELF7 regulate H3.3 deposition, and are necessary for the high temperature-induced H3.3 enrichment at PIF4 targets. Our findings demonstrate close coordination between H2A.Z eviction and H3.3 deposition in gene activation induced by high temperature, and pinpoint the importance of histone variants dynamics in transcriptional regulation.
摘要：
植物可以感知温度变化，并在称为热形态发生的过程中相应地调整其发育和形态。这种表型可塑性暗示了调节基因表达重编程以响应环境改变的复杂机制。组蛋白变体通常与特定的染色质状态相关，然而，它们的沉积/驱逐如何调节由环境线索引起的转录变化仍然难以捉摸。在拟南芥中，温度升高诱导的热响应基因的转录激活需要组蛋白变体H2A的染色质驱逐。Z通过INO80，通过与关键的热形态发生调节因子PIF4相互作用被招募到这些基因座。这里,我们表明INO80和另一个组蛋白变体H3.3的沉积伴侣都与ELF7相关，ELF7是转录延伸子PAF1复合物的关键成分。H3.3在PIF4靶标处促进热形态发生和高温增强的RNAPolII转录，H2A广泛需要它。Z去除诱导的基因激活。相互,INO80和ELF7调节H3.3沉积，并且是高温诱导的PIF4靶标上H3.3富集所必需的。我们的发现证明了H2A之间的密切协调。高温诱导的基因激活中的Z驱逐和H3.3沉积，并指出组蛋白变体动力学在转录调控中的重要性。
