Lee Hong Gil, Hong Cheljong, Seo Pil Joon
Department of Chemistry, Seoul National University, Seoul, South Korea.
Plant Genomics and Breeding Institute, Seoul National University, Seoul, South Korea.
Front Plant Sci. 2019 Feb 18;10:171. doi: 10.3389/fpls.2019.00171. eCollection 2019.
The circadian clock synchronizes endogenous rhythmic processes with environmental cycles and maximizes plant fitness. Multiple regulatory layers shape circadian oscillation, and chromatin modification is emerging as an important scheme for precise circadian waveforms. Here, we report the role of an evolutionarily conserved Sin3-histone deacetylase complex (HDAC) in circadian oscillation in . () and , which are key components of Sin3-HDAC complex, are circadianly-regulated and possibly facilitate the temporal formation of the Sin3-HDAC complex at dusk. The evening-expressed AFR proteins bind directly to the () and () promoters and catalyze histone 3 (H3) deacetylation at the cognate regions to repress expression, allowing the declining phase of their expression at dusk. In support, the and genes were de-repressed around dusk in the double mutant. These findings indicate that periodic histone deacetylation at the morning genes by the Sin3-HDAC complex contributes to robust circadian maintenance in higher plants.
生物钟将内源性节律过程与环境周期同步，从而使植物适应性最大化。多个调控层次塑造了昼夜节律振荡，而染色质修饰正成为精确昼夜节律波形的重要机制。在此，我们报道了一种进化上保守的Sin3-组蛋白去乙酰化酶复合体（HDAC）在[具体植物名称未给出]昼夜节律振荡中的作用。Sin3-HDAC复合体的关键组分[具体基因名称未给出]和[具体基因名称未给出]受昼夜节律调控，且可能在黄昏时促进Sin3-HDAC复合体的适时形成。傍晚表达的AFR蛋白直接结合到[具体基因名称未给出]和[具体基因名称未给出]的启动子上，并催化同源区域的组蛋白3（H3）去乙酰化以抑制表达，使其在黄昏时表达量下降。作为证据，在[具体双突变体名称未给出]双突变体中，[具体基因名称未给出]和[具体基因名称未给出]基因在黄昏前后去抑制。这些发现表明，Sin3-HDAC复合体对早晨基因进行周期性组蛋白去乙酰化作用，有助于高等植物维持稳健的昼夜节律。
