Isolation of Genes Regulated by Peroxisome Proliferator-Activated Receptor γ (PPARγ) by Two-Dimensional Electrophoresis and Mass Spectrometry

Abstract

To isolate the genes regulated by peroxisome proliferator-activated receptor γ (PPARγ), we first developed a stable transformant expressing PPARγ. Using cytosol and nuclear fractions prepared from this cell line, we performed two-dimensional electrophoresis. A comparison of the electrophoretic patterns with those from control cells revealed many spots to be up-regulated or down-regulated proteins. Some spots were subjected to mass spectrometric analyses, and triosephosphate isomerase and galectin-3 were identified as proteins down-regulated by PPARγ. Moreover, Northern blot analyses revealed that the expression level of both genes decreased in PPARγ-expressing cells. These results strongly suggest that triosephosphate isomerase and galectin-3 are target genes whose expression is mediated by PPARγ.