The circadian clock acts at the genomic level to coordinate internal behavioral and physiologic rhythms via the CLOCK-BMAL transcriptional heterodimer. Although the nuclear receptors REV-ERBα and β have been proposed to contribute to clock function, their precise roles and importance remain unresolved. To establish their regulatory potential we generated comparative cistromes of both Rev-erb isoforms, which revealed shared recognition at over ~50% of their total sites and extensive overlap with the master clock regulator Bmal. While Rev-erbα has been shown to directly regulate Bmal expression, the cistromic analysis reveals a more profound connection between Bmal and Rev-erbα and β regulatory circuits than previously suspected. Genes within the intersection of the Bmal and Rev-erb cistromes are highly enriched for both clock and metabolic functions. As predicted by the cistromic analysis, dual depletion of Rev-erbα/β function by creating double-knockout mice (DKOs) profoundly disrupted circadian expression of core clock and lipid homeostatic genes. As a result, DKOs show strikingly altered circadian wheel-running behavior and deregulated lipid metabolism. These data reveal an integral role of Rev-erbα/β in clock function as well as provide a cistromic basis for the integration of circadian rhythm and metabolism.
Total RNA was obtained from livers of wild-type and Liver-specific Reverb alpha/beta double knockout mice at ZT 0, 4, 8, 12, 16, and 20.