Functional Analysis of Promoters of Genes in Lipid Metabolism and Their Transcriptional Response to STAT3 under Leptin Signals.

We characterized the promoters of target genes of the signal transducer and activator of transcription 3, STAT3 (carnitine palmitoyltransferase I, , acetyl-CoA carboxylase alpha, ; fatty acid synthase, ; and peroxisome proliferator-activated receptor gamma, ) in a teleost . Binding sites of STAT3 were predicted on these promoters, indicating that STAT3 probably mediated their transcriptional activities. Leptin had no effect on the activity of and promoters, but increased promoter activity and decreased promoter activity. The −979/−997 STAT3 binding site of and the −794/−812 STAT3 binding site of were functional binding loci responsible for leptin-induced transcriptional activation. The study provided direct evidence that STAT3 regulated the expression of and at the transcription level, and determined the STAT3 response element on promoters of and under leptin signal.