In mouse 3T3-L1 cells, the PPARG:RXRA heterodimer binds specific the PPRE element, two 6-bp DR-1 motifs separated by 1 nucleotide, in the promoters of target genes such as aP2/Fabp4 even in the absence of fatty acid ligands that activate PPARG (IJpenberg et al. 1997, Okuno et al. 2001). When activating ligands of PPARG are absent PPARG:RXRA recruits corepressors such as Smrt, NCoR, and Hdac33 to maintain the target gene in an inactive state (Tontonoz et al. 1994, Yu et al. 2005, Yoo et al. 2006).