Millet L, Vidal H, Larrouy D, Andreelli F, Laville M, Langin D
INSERM U317, Institut Louis Bugnard, Université Paul Sabatier, Hôpital Rangueil, Toulouse, France.
Diabetologia. 1998 Jul;41(7):829-32. doi: 10.1007/s001250050994.
Uncoupling protein-3 (UCP3) is a mitochondrial protein expressed in skeletal muscle, an important site of thermogenesis in humans. By uncoupling respiration from ATP synthesis, UCP3 might be involved in the control of energy expenditure. Two transcripts encoding long (UCP3L) and short (UCP3S) form are generated from the human UCP3 gene. UCP3S is predicted to encode a protein which lacks the C-terminus of UCP3L, a region which contains motifs critical for uncoupling activity. We have investigated the regulation of UCP3L and UCP3S mRNAs in lean and obese humans. A specific reverse transcription-competitive polymerase chain reaction assay was developed to separately quantify the two mRNAs. Each transcript represents half of total UCP3 mRNA in 16 vastus lateralis muscle samples. The amounts of UCP3L and UCP3S mRNAs did not differ between obese and lean subjects. The effect of fasting was studied in six lean and seven obese subjects maintained on a hypocaloric diet (1045 kJ/d) for 5 days. Calorie restriction results in an approximately threefold increase of UCP3L and UCP3S mRNA levels. The induction was similar in lean and obese subjects. The data suggest that there is no major alteration of UCP3 gene expression and regulation at the level of transcription and alternative splicing in skeletal muscle of obese subjects.
解偶联蛋白3（UCP3）是一种在骨骼肌中表达的线粒体蛋白，骨骼肌是人体产热的重要部位。通过使呼吸与ATP合成解偶联，UCP3可能参与能量消耗的控制。人类UCP3基因产生两种编码长型（UCP3L）和短型（UCP3S）的转录本。预测UCP3S编码的蛋白质缺少UCP3L的C末端，该区域包含对解偶联活性至关重要的基序。我们研究了瘦人和肥胖人群中UCP3L和UCP3S mRNA的调控情况。开发了一种特异性逆转录竞争聚合酶链反应测定法来分别定量这两种mRNA。在16个股外侧肌样本中，每种转录本占UCP3 mRNA总量的一半。肥胖和瘦人受试者之间UCP3L和UCP3S mRNA的量没有差异。对6名瘦人和7名肥胖受试者进行了研究，他们维持低热量饮食（1045千焦/天）5天，以观察禁食的影响。热量限制导致UCP3L和UCP3S mRNA水平增加约三倍。瘦人和肥胖受试者中的诱导情况相似。数据表明，肥胖受试者骨骼肌中UCP3基因在转录和可变剪接水平上的表达和调控没有重大改变。
