University of Heidelberg Biochemistry Center (BZH), Im Neuenheimer Feld 328, 69120 Heidelberg, Germany.
FEBS Lett. 2011 May 20;585(10):1443-9. doi: 10.1016/j.febslet.2011.04.008. Epub 2011 Apr 7.
Circadian clocks allow a temporal coordination and segregation of physiological, metabolic, and behavioural processes as well as their synchronization with the environmental cycles of day and night. Circadian regulation thereby provides a vital advantage, improving an organisms' adaptation to its environment. The molecular clock can be synchronized with environmental cycles of day and night, but is able to maintain a self-sustained molecular oscillation also in the absence of environmental stimuli. Interlocked transcriptional-translational feedback loops were shown to form the basis of circadian clock function in all phyla from bacteria, fungi, plants, insects to humans. More recently post-translational regulation was identified to be equally important, if not sufficient for molecular clock function and accurate timing of circadian transcription. Here we review recent insights into post-translational timing mechanisms that control the circadian clock, with a particular focus on Drosophila. Analogous to transcriptional feedback regulation, circadian clock function in Drosophila appears to rely on inter-connected post-translational timers. Post-translational regulation of clock proteins illustrates mechanisms that allow a precise temporal control of transcription factors in general and of circadian transcription in particular.
生物钟使生理、代谢和行为过程具有时间协调性和分隔性,并使其与昼夜环境周期同步。因此,生物钟调节提供了至关重要的优势,提高了生物体对环境的适应能力。分子钟可以与昼夜环境周期同步,但即使在没有环境刺激的情况下,也能够维持自身持续的分子振荡。已经表明,转录-翻译反馈环的互锁构成了从细菌、真菌、植物、昆虫到人类所有生物门类的生物钟功能的基础。最近发现,翻译后调控对于分子钟功能和生物钟转录的精确计时同样重要,如果不是充分的话。在这里,我们回顾了控制生物钟的最新的翻译后定时机制的见解,特别关注果蝇。类似于转录反馈调节,果蝇的生物钟功能似乎依赖于相互连接的翻译后定时器。生物钟蛋白的翻译后调控说明了允许一般转录因子和特定的生物钟转录进行精确时间控制的机制。