Discrete Functions of Rev-erba Couple Metabolism to the Clock [array]

Circadian and metabolic physiology are intricately intertwined, as illustrated by Rev-erb , a transcription factor (TF) that functions both as a core repressive component of the cell autonomous clock and as a regulator of metabolic genes. Here we show that Rev-erb modulates the clock and metabolism by different genomic mechanisms. Clock control requires Rev-erb to bind directly to the genome at its cognate sites, where it competes with activating ROR TFs. By contrast, Rev-erb regulates metabolic genes primarily by recruiting the HDAC3 corepressor to sites to which it is tethered by cell type-specific transcription factors. Thus, direct competition between Rev-erb and ROR TFs provides a universal mechanism for self-sustained control of molecular clock across all tissues, whereas Rev-erb utilizes lineage-determining factors to convey a tissue-specific epigenomic rhythm that regulates metabolism tailored to the specific need of that tissue. Gene expressions in wild type and RORs depleted mouse livers were compared using Affymetrix MoGene2.0st array. Four biological replicates were used for each condition.