The reporter assay was performed as described elsewhere (55 (link), 56 (link)). On day 0, HEK293T cells were set up for experiments in 0.5 mL of DMEM (10-013-CV; Corning) supplemented with 10% FBS (16000044; Thermo Fisher Scientific) at a density of 30,000 cells per well in 24-well plates. On day 1, cells were cotransfected with 0.125 ng of pTK-Renilla luciferase, 12.5 ng of pLE1-firefly luciferase or pLE2-firefly luciferase, 162.7 ng of pCMV-PPARγ, and 162.7 ng of pCMV-RXRα. Fugene 6 was used as the transfection agent. For each transfection, the total amount of DNA was adjusted to 338 ng per dish by the addition of pcDNA mock vector. On day 2, the cells were treated with 1 μM rosiglitazone (Sigma) in DMSO, 1 μM 9-cis-Retinoic acid (Sigma–Aldrich) in DMSO, or DMSO alone. On day 3, the cells were washed with PBS, after which luciferase activity was read on a CLARIOstar (BMG Labtech) using the Dual-Luciferase Reporter Assay System (Promega). The amount of LE1 (or LE2) luciferase activity in each dish was normalized to the amount of Renilla luciferase activity in the same dish. A relative luciferase activity of 1 represents the normalized luciferase value in dishes transfected with pcDNA mock vector with DMSO treatment. All values are the average of duplicate assays.