Jones Matthew A, Morohashi Kengo, Grotewold Erich, Harmer Stacey L
School of Biological Sciences, University of Essex, Colchester, United Kingdom.
Department of Plant Biology, University of California, Davis, Davis, CA, United States.
Front Plant Sci. 2019 Feb 1;10:57. doi: 10.3389/fpls.2019.00057. eCollection 2019.
The circadian system ensures that plants respond appropriately to environmental change by predicting regular transitions that occur during diel cycles. In order to be most useful, the circadian system needs to be compensated against daily and seasonal changes in temperature that would otherwise alter the pace of this biological oscillator. We demonstrate that an evening-phased protein, the putative histone demethylase JMJD5, contributes to temperature compensation. is co-expressed with components of the Evening Complex, an agglomeration of proteins including EARLY FLOWERING3 (ELF3), ELF4, and LUX ARRHYTHYMO (LUX), which also integrates temperature changes into the molecular clockwork. One role of the Evening Complex is to regulate expression of () and , important components of the temperature compensation mechanism. Surprisingly we find that LUX, but not other Evening Complex components, is dispensable for clock function at low temperatures. Further genetic analysis suggests JMJD5 acts in a parallel pathway to LUX within the circadian system. Although an intact JMJD5 catalytic domain is required for its function within the clock, our findings suggest JMJD5 does not directly regulate H3K36 methylation at circadian loci. Such data refine our understanding of how JMDJ5 acts within the Arabidopsis circadian system.
昼夜节律系统通过预测昼夜循环中发生的规律性转变，确保植物对环境变化做出适当反应。为了发挥最大作用，昼夜节律系统需要针对温度的每日和季节性变化进行补偿，否则这些变化会改变这个生物振荡器的节奏。我们证明，一种傍晚表达的蛋白质，即假定的组蛋白去甲基化酶JMJD5，有助于温度补偿。它与傍晚复合体的组分共同表达，傍晚复合体是一种蛋白质聚集体，包括早花3（ELF3）、ELF4和LUX ARRHYTHYMO（LUX），该复合体也将温度变化整合到分子生物钟机制中。傍晚复合体的一个作用是调节温度补偿机制的重要组分（）和的表达。令人惊讶的是，我们发现在低温下，LUX而非其他傍晚复合体组分对于生物钟功能是可有可无的。进一步的遗传学分析表明，JMJD5在昼夜节律系统中与LUX处于平行途径发挥作用。虽然完整的JMJD5催化结构域是其在生物钟内发挥功能所必需的，但我们的研究结果表明，JMJD5并不直接调节昼夜节律位点处的H3K36甲基化。这些数据完善了我们对JMDJ5在拟南芥昼夜节律系统中作用方式的理解。
