Brown fat cells are specialized to dissipate energy and can counteract obesity; however, the transcriptional basis of their determination is largely unknown. We show here that the zinc-finger protein PRDM16 is highly enriched in brown fat cells compared to white fat cells. When expressed in white fat cell progenitors, PRDM16 activates a robust brown fat phenotype including induction of PGC-1α, UCP1, and type 2 deiodinase (Dio2) expression and a remarkable increase in uncoupled respiration. Transgenic expression of PRDM16 at physiological levels in white fat depots stimulates the formation of brown fat cells. Depletion of PRDM16 through shRNA expression in brown fat cells causes a near total loss of the brown characteristics. PRDM16 activates brown fat cell identity at least in part by simultaneously activating PGC-1α and PGC-1β through direct protein binding. These data indicate that PRDM16 can control the determination of brown fat fate.
