Benegiamo Giorgia, Brown Steven A, Panda Satchidananda
Institute of Pharmacology and Toxicology, University of Zürich, Winterthurerstrasse 190, Zürich, 8057, Switzerland.
Salk Institute for Biological Studies, 10010, North Torrey Pines Road, La Jolla, CA, 92037, USA.
Adv Exp Med Biol. 2016;907:107-22. doi: 10.1007/978-3-319-29073-7_5.
The circadian oscillator is based on transcription-translation feedback loops that generate 24 h oscillations in gene expression. Although circadian regulation of mRNA expression at the transcriptional level is one of the most important steps for the generation of circadian rhythms within the cell, multiple lines of evidence point to a disconnect between transcript oscillation and protein oscillation. This can be explained by regulatory RNA-binding proteins acting on the nascent transcripts to modulate their processing, export, translation and degradation rates. In this chapter we will review what is known about the different steps involved in circadian gene expression from transcription initiation to mRNA stability and translation efficiency. The role of ribonucleoprotein particles in the generation of rhythmic gene expression is only starting to be elucidated, but it is likely that they cooperate with the basal transcriptional machinery to help to maintain the precision of the clock under diverse cellular and environmental conditions.
昼夜节律振荡器基于转录-翻译反馈环，该反馈环在基因表达中产生24小时振荡。虽然转录水平上mRNA表达的昼夜节律调节是细胞内产生昼夜节律的最重要步骤之一，但多条证据表明转录本振荡与蛋白质振荡之间存在脱节。这可以通过作用于新生转录本以调节其加工、输出、翻译和降解速率的调节性RNA结合蛋白来解释。在本章中，我们将综述从转录起始到mRNA稳定性和翻译效率等昼夜节律基因表达所涉及的不同步骤的已知情况。核糖核蛋白颗粒在节律性基因表达产生中的作用才刚刚开始被阐明，但它们可能与基础转录机制协同作用，以帮助在不同的细胞和环境条件下维持生物钟的精度。
