Department of Plant Physiology, Umea Plant Science Centre, Umea University, SE-901 87 Umea, Sweden.
Plant Physiol. 2011 Apr;155(4):2108-22. doi: 10.1104/pp.110.167155. Epub 2011 Feb 7.
The circadian clock of the model plant Arabidopsis (Arabidopsis thaliana) is made up of a complex series of interacting feedback loops whereby proteins regulate their own expression across day and night. early bird (ebi) is a circadian mutation that causes the clock to speed up: ebi plants have short circadian periods, early phase of clock gene expression, and are early flowering. We show that EBI associates with ZEITLUPE (ZTL), known to act in the plant clock as a posttranslational mediator of protein degradation. However, EBI is not degraded by its interaction with ZTL. Instead, ZTL counteracts the effect of EBI during the day and increases it at night, modulating the expression of key circadian components. The partnership of EBI with ZTL reveals a novel mechanism involved in controlling the complex transcription-translation feedback loops of the clock. This work highlights the importance of cross talk between the ubiquitination pathway and transcriptional control for regulation of the plant clock.
模式植物拟南芥（Arabidopsis thaliana）的生物钟由一系列复杂的相互作用反馈环组成，蛋白质在昼夜之间调节自身的表达。早期鸟（ebi）是一种生物钟突变，导致生物钟加速：ebi 植物的生物钟周期短，时钟基因表达的早期阶段早，并且开花早。我们表明，EBI 与 ZEITLUPE（ZTL）相关联，已知在植物生物钟中作为蛋白质降解的翻译后中介物发挥作用。然而，EBI 并没有通过与 ZTL 的相互作用而降解。相反，ZTL 在白天抵消 EBI 的作用，晚上增加其作用，调节关键生物钟成分的表达。EBI 与 ZTL 的伙伴关系揭示了一种控制时钟复杂转录-翻译反馈环的新机制。这项工作强调了泛素化途径和转录控制之间的相互作用对于植物生物钟调控的重要性。
