Gene expression data from differentiating 3T3-L1 cells

The MED1 subunit has been shown to mediate ligand-dependent binding of the Mediator coactivator complex to multiple nuclear receptors, including the adipogenic PPARγ, and to play an essential role in ectopic PPARγ-induced adipogenesis of mouse embryonic fibroblasts. However, the precise roles of MED1, and its various domains, at various stages of adipogenesis and in adipose tissue have been unclear. Here, after establishing requirements for MED1, including specific domains, for differentiation of 3T3L1 cells and both primary white and brown preadipocytes, we used multiple genetic approaches to assess requirements for MED1 in adipocyte formation and function in mice. We show that MED1 is indeed essential for the differentiation and/or function of both brown and white adipocytes, as its absence in these cells leads to, respectively, defective brown fat function and lipodystrophy. This work establishes MED1 as an essential transcriptional coactivator that ensures the formation and homeostatic functions of adipocytes. MED1-KO 3T3-L1 clones were generated using CRISPR/Cas9, and differentiated along with their parental WT 3T3-L1 cells. Pools of RNA fro individual KO clones at Day0 and Day2 of differentiation were subjected to microarray analysis together with the WT 3T3-L1 cells to identify MED1-dependent transcriptional events during early phase of adipogenesis in culture. The role of MED1 in brown adipose tissue formation and function was also examined using microarray in Myf5-Cre as well as AdipoqCre- based Med1 conditional knockout models.