Molecular cloning and characterization of olive flounder (Paralichthys olivaceus) peroxisome proliferator-activated receptor γ

Peroxisome proliferator-activated receptors (PPARs) are nuclear hormone receptors that play key roles in lipid and energy homeostasis. Olive flounder (Paralichthys olivaceus) PPAR gamma cDNA (olPPAR gamma) was isolated by reverse transcription-polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends (RACE). The full-length cDNA is 1667-bp long and encodes a polypeptide with 532 amino acids containing a C4-type zinc finger and a ligand-binding domain. Quantitative RT-PCR revealed that olPPAR gamma transcription was detected from 7 days post-hatching, and its expression was increased under a starved condition. Overexpression of olPPAR gamma stimulated PPAR response element (PPRE) activity, and treatment with rosiglitazone, a PPAR gamma agonist, augmented olPPAR gamma-stimulated PPRE activity in HINAE olive flounder cells. Cotransfection of olPPAR gamma and olRXR beta, in the absence or presence of rosiglitazone and ciglitazone, produced a synergistic effect on PPRE transactivation in 3T3L1 adipocytes. Moreover, olPPAR gamma, in the presence or absence of rosiglitazone, regulated the expression of lipid synthesis- and adipogenesis-related proteins in NIH3T3 and 3T3L1 cells. Taken together, these results suggest that olPPAR gamma is functionally and evolutionarily conserved in olive flounder and mammals. (C) 2009 Published by Elsevier Inc.