Molecular cloning and characterization of peroxisome proliferator‐activated receptor‐¥ã from olive flounder, Paralichthys olivaceus

Peroxisome proliferator‐activated receptor‐gamma (PPARγ) is a ligand‐activated transcription factor of the nuclear receptor superfamily that regulates genes involved in differentiation, metabolism and immunity. The cDNA sequences of PPARγ was isolated from olive flounder, Paralichthys olivaceus using reverse transcription‐polymerase chain reaction (RT‐PCR) and rapid amplification of cDNA ends (RACE). The full length of cDNA sequence is 1667 bp long and encodes a polypeptide with 532 amino‐acid residues containing C4‐type zinc finger and ligand binding domain. Semi‐quantitative RT‐PCR analysis revealed PPARγ mRNAs were broadly expressed in various tissues except muscle and heart. In addition, PPARγ expressions were detected from the early stage of development. In olive flounder embryonic cell line HINAE, overexpression of olive flounder PPARγ stimulated PPAR response element (PPRE)‐minimum promoter in a ligand‐dependent manner and the treatment of rosiglitazone, PPARγ agonist, elevated the mRNA levels of PPARγ but decreased that of PPARα. In mammalian cells, olive flounder PPARγ either alone or in conjunction with rosiglitazone induced expression of lipid synthesis‐related genes. Taken together, these results suggest that PPARγ may be present in olive flounder.