Functional organization of the human uncoupling protein-2 gene, and juxtaposition to the uncoupling protein-3 gene

Human and mouse UCP2 genes were cloned and sequenced. Transcriptional start sites were identified using primer extension analysis. The transcription u nit of UCP2 gene is made of 2 untranslated exons followed by 6 exons encodi ng UCP2. In vitro translation analysis demonstrated that an open-reading-fr ame for a putative peptide of 36 residues present in exon 2 did not prevent UCP2 translation and confirmed that the initiation site of translation was in exon 3 as predicted from sequencing data. Short (bp -125 to +93) and lo ng (bp -1383 and +93) CAT-constructs containing DNA upstream of the transcr iptional start site of the human gene were made and transfected in adipocyt es or HeLa cells allowing characterization of a potent promoter. Analysis o f several genomic clones encompassing UCP2 and/or UCP3 genes demonstrated t hat the 2 genes are adjacent, the human UCP2 gene being located 7 kb downst ream of the UCP3 gene. (C) 1999 Academic Press.