Circadian Clock Regulates Dynamic Chromatin Modifications Associated with Arabidopsis CCA1/LHY and TOC1 Transcriptional Rhythms
Circadian Clock Regulates Dynamic Chromatin Modifications Associated with Arabidopsis CCA1/LHY and TOC1 Transcriptional Rhythms
复制标题
DOI：
10.1093/pcp/pcs148
复制
发表时间：
2012-12-01
影响因子：
4.9
通讯作者：
Chua, Nam-Hai
中科院分区：
文献类型：
--
作者：
Hemmes, Hans;Henriques, Rossana;Chua, Nam-Hai
生物钟使生物体能够适应24小时的昼夜循环，并预测环境的节律变化。拟南芥的中央振荡器包含三个基因编码的核心时钟组件。昼夜节律相关基因1（CCA 1）/晚伸长下胚轴（LHY）和CAB表达时间1（TOC 1）共同抑制彼此编码的基因，并且对于控制许多时钟输出的昼夜节律的产生至关重要。因此，转录事件的精确调节对于适当的昼夜节律功能至关重要。在这里，我们研究了组蛋白3（H3）尾部修饰的CCA 1，LHY和TOC 1在各种条件下。我们发现只有H3 K4 Me 3和H3 K9/14 Ac与这三个基因的翻译起始位点特异性相关。这些H3标记在不同光周期和自由运行条件下在转录增加的昼夜节律时间点富集，表明H3修饰的昼夜节律调节。对时钟受损的CCA 1过表达株系的分析提供了证据，证明亮/暗光周期信号建立了这些由时钟门控的染色质变化。
Circadian clocks enable organisms to adapt to a 24 h diurnal cycle and anticipate rhythmic changes in the environment. The Arabidopsis central oscillator contains three genes encoding core clock components. CIRCADIAN CLOCK ASSOCIATED 1 (CCA1)/LATE ELONGATED HYPOCOTYL (LHY) and TIMING OF CAB EXPRESSION 1 (TOC1) reciprocally repress genes encoding each other and are critical for the generation of circadian rhythms controlling many clock outputs. A precise regulation of transcriptional events is, therefore, essential for proper circadian function. Here, we investigated histone 3 (H3) tail modifications of CCA1, LHY and TOC1 under various conditions. We found specific association of only H3K4Me3 and H3K9/14Ac with the translational start site of these three genes. These H3 marks were enriched at circadian time points of their increased transcription at different photoperiods and under free-running conditions, suggesting circadian regulation of H3 modifications. Analysis of clock-compromised CCA1-overexpressing lines provided evidence that light/dark photoperiods signal the establishment of these chromatin changes which are gated by the clock.