Uncoupling protein 1 (Ucp1) contributes to thermogenesis, and its expression is regulated at the transcriptional level. Here, we show that Ucp1 expression is also regulated post-transcriptionally. In inguinal white adipose tissue (iWAT) of mice fed a high-fat diet (HFD), Ucp1 level decreases concomitantly with increases in Cnot7 and its interacting partner Tob. HFD-fed mice lacking Cnot7 and Tob express elevated levels of Ucp1 mRNA in iWAT and are resistant to diet-induced obesity. Ucp1 mRNA has an elongated poly(A) tail and persists in iWAT of Cnot7−/− and/or Tob−/− mice on a HFD. Ucp1 3′-UTR-containing mRNA is more stable in cells expressing mutant Tob that is unable to bind Cnot7 than in WT Tob-expressing cells. Tob interacts with BRF1, which binds to an AU-rich element in the Ucp1 3′-UTR. BRF1 knockdown partially restores the stability of Ucp1 3′-UTR-containing mRNA. Thus, the Cnot7-Tob-BRF1 axis inhibits Ucp1 expression and contributes to obesity. Takahashi et al. show that the BRF1-Tob-Cnot7 axis exacerbates obesity by post-transcriptionally suppressing Ucp1 mRNA in iWAT of obese mice. BRF1, which recognizes AU-rich elements, binds to the Ucp1 3′-UTR and interacts with Tob. Tob recruits Cnot7 to deadenylate the Ucp1 mRNA poly(A) tail, resulting in Ucp1 mRNA degradation.
ASJC Scopus subject areas
- Biochemistry, Genetics and Molecular Biology(all)