MOLECULAR-CLONING, EXPRESSION AND CHARACTERIZATION OF HUMAN PEROXISOME PROLIFERATOR ACTIVATED RECEPTORS GAMMA-1 AND GAMMA-2

We describe the molecular cloning and expression of cDNAs encoding hum an PPAR gamma 1 and PPAR gamma 2. Our sequences are distinct from the published sequence at 3 positions, resulting in nonconservative amino acid substitutions. In humans, PPAR gamma mRNA is expressed in spleen, bone marrow, liver, testis, skeletal muscle and brain, in addition to fat. Three thiazolidinediones were found to 1) displace a radiolabele d thiazolidinedione from both receptors with essentially the same IC(5 0)s and 2) to transactivate both PPAR gamma isoforms with similar EC(5 0)s in transient cotransfection assays utilizing the adipocyte-specifi c aP2 promoter. Saturating concentrations of these 3 thiazolidinedione s altered the conformation of in vitro synthesized PPAR gamma protein producing a 27 kDa protease-resistant fragment. These results indicate that the antidiabetic effects of thiazolidinediones in humans are lik ely to be mediated via binding to and transactivation of PPAR gamma 1 and gamma 2. (C) 1996 Academic Press, Inc.