Nuclear Receptor Corepressor-Histone Deacetylase 3 Governs Circadian Metabolic Physiology

Rhythmic changes in histone acetylation at circadian clock genes suggest that temporal modulation of gene expression is regulated by chromatin modifications1–3. Furthermore, recent studies demonstrate a critical relationship between circadian and metabolic physiology4–7. The Nuclear Receptor Co-Repressor 1 (NCoR) functions as an activating subunit for the chromatin modifying enzyme histone deacetylase 3 (HDAC3)8. Lack of NCoR is incompatible with life, and hence it is unknown whether NCoR, and particularly its regulation of HDAC3, is critical for adult mammalian physiology9. Here we show that specific, genetic disruption of the NCoR-HDAC3 interaction in mice causes aberrant regulation of clock genes and results in abnormal circadian behavior. These mice are also leaner and more insulin sensitive due to increased energy expenditure. Unexpectedly, loss of a functional NCoR-HDAC3 complex in vivo does not lead to sustained elevations of known catabolic genes, but rather significantly alters the oscillatory patterns of several metabolic genes, demonstrating that circadian regulation of metabolism is critical for normal energy balance. These findings indicate that activation of HDAC3 by NCoR is a nodal point in the epigenetic regulation of circadian and metabolic physiology.