Circadian post-transcriptional control of metabolism

Circadian clocks control thousands of genes, which ultimately generate rhythms in signaling pathways, metabolism, tissue physiology and behavior. Although rhythmic transcription plays a critical role in generating these rhythmic gene expression patterns, recent evidence has shown that post-transcriptional mechanisms are also important. Here we describe studies showing that regulation of mRNA poly(A) tail length is under circadian control and that these changes contribute to rhythmic protein expression independently of transcription. Nocturnin, a circadian deadenylase that shortens poly(A) tails, contributes to this type of circadian post-transcriptional regulation. The importance of tail-shortening by Nocturnin is evident from the phenotype of mice lacking Nocturnin, which exhibit resistance to diet-induced obesity and other metabolic changes.