Transcriptional regulation of uncoupling protein-2 gene expression in L6 myotubes

Int J Obes Relat Metab Disord. 2001 Nov;25(11):1619-24. doi: 10.1038/sj.ijo.0801812.


Objective: To increase the understanding of the transcriptional regulation of UCP2 gene expression in skeletal muscle cells, we examined the effect of all-trans-retinoic acid (tRA), a ligand (after the conversion to 9-cis-RA) of the retinoid X receptor (RXR), and linolenic acid, a polyunsaturated fatty acid and peroxisome proliferator-activated receptors (PPARs) ligand, on the expression of UCP2 mRNA in cultured L6 myotubes.

Research methods and procedures: UCP2 gene expression in L6 myotubes was confirmed by Northern blot analysis. The time- and concentration-dependency of tRA and linolenic acid on UCP2 gene expression was assessed by dot blot quantification. The mRNA levels of PPAR subtypes (alpha, gamma and delta) were determined by RT-PCR.

Results: tRA induced UCP2 gene expression in a time- and concentration-dependent manner. Similar to tRA, UCP2 mRNA was markedly increased by 0.5 mM linolenic acid. In L6 myotubes, PPARdelta mRNA was abundant, whereas PPARalpha mRNA was lower and PPARgamma mRNA was minimal.

Conclusions: UCP2 mRNA expression in L6 myotubes is up-regulated by tRA and linolenic acid, possibly through a mechanism involving PPAR and RXRs.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Blotting, Northern
  • Cells, Cultured
  • DNA Primers
  • Dose-Response Relationship, Drug
  • Gene Expression Regulation
  • Ion Channels
  • Membrane Transport Proteins*
  • Mitochondrial Proteins*
  • Muscle, Skeletal / cytology*
  • Proteins / genetics*
  • RNA, Messenger / drug effects
  • RNA, Messenger / genetics
  • Rats
  • Receptors, Cytoplasmic and Nuclear / administration & dosage
  • Receptors, Retinoic Acid / drug effects
  • Receptors, Retinoic Acid / genetics
  • Retinoid X Receptors
  • Reverse Transcriptase Polymerase Chain Reaction
  • Transcription Factors / administration & dosage
  • Transcription Factors / drug effects
  • Transcription Factors / genetics
  • Transcription Factors / pharmacology
  • Transcription, Genetic
  • Tretinoin / administration & dosage
  • Tretinoin / pharmacology
  • Uncoupling Protein 2
  • alpha-Linolenic Acid / administration & dosage
  • alpha-Linolenic Acid / pharmacology


  • DNA Primers
  • Ion Channels
  • Membrane Transport Proteins
  • Mitochondrial Proteins
  • Proteins
  • RNA, Messenger
  • Receptors, Cytoplasmic and Nuclear
  • Receptors, Retinoic Acid
  • Retinoid X Receptors
  • Transcription Factors
  • Ucp2 protein, rat
  • Uncoupling Protein 2
  • alpha-Linolenic Acid
  • Tretinoin