Functional characterization of the 5 '-flanking and the promoter region ofthe human UCP3 (hUCP3) gene

Uncoupling protein-3 (UCP3) is considered as an important regulator of ener gy expenditure and thermogenesis in humans. To get insight into the mechani sms regulating its expression we have cloned and characterized about 5 kb o f the 5'-flanking region of the human UCP3 (hUCP3) gene. 5'-RACE analysis s uggested a single transcription initiation site 187 bp upstream from the tr anslational start site. The promoter region contains both TATA and CAAT box es as well as consensus motifs for PPRE, TRE, CRE and muscle-specific facto rs like MyoD and MEF2 sites. Functional characterization of a 3 kb hUCP3 pr omoter fragment in multiple cell lines using a CAT-ELISA identified a cl-ac ting negative regulatory element between -2983 and -982 while the region be tween -982 and -284 showed greatly increased basal promoter activity sugges ting the presence of a strong enhancer element. Promoter activity was parti cularly enhanced in the murine skeletal muscle cell line C2C12 reflecting t he tissue-selective expression pattern of UCP3. (C) 2000 Elsevier Science I nc. All rights reserved.