for chromatin immunoprecipitation ( chip ) , 5 month - old male c57bl/6j mice were euthanized by co2 asphyxiation at zt 8 .
tamoxifen - induction of cre recombinase activity was accomplished by daily intraperitoneal injection of 2 mg tamoxifen ( sigma ) in 100l corn oil ( sigma ) for 7 days .
3 month - old tamoxifen - treated animals were subjected to wheel running assays for 7 days after the end of treatment . for gene expression analysis
, 56 month - old males were euthanized by cervical dislocation at indicated zt points for rapid dissection and snap - freezing of the tissues . during the dark cycle , procedures were performed under red light .
 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 - erb and  have been proposed to form an accessory feedback loop that contributes to clock function1,2 , 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 circadian regulator bmal1 . while rev - erb has been shown to directly regulate bmal1 expression1,2 , the cistromic analysis reveals a direct connection between bmal1 and rev - erb and  regulatory circuits than previously suspected . 
 genes within the intersection of the bmal1 , rev - erb and rev - erb cistromes are highly enriched for both clock and metabolic functions . 
 as predicted by the cistromic analysis , dual depletion of rev - erb/ function by creating double - knockout mice ( dkos ) profoundly disrupted circadian expression of core circadian clock and lipid homeostatic gene networks . 
 as a result , dkos show strikingly altered circadian wheel - running behavior and deregulated lipid metabolism . 
 these data now ally rev - erb/ with per , cry and other components of the principal feedback loop that drives circadian expression and suggest a more integral mechanism for the coordination of circadian rhythm and metabolism . 
Methods Summary
Supplementary Material