MicroRNA-1 and microRNA-133a expression are decreased during skeletal muscle hypertrophy

J Appl Physiol (1985). 2007 Jan;102(1):306-13. doi: 10.1152/japplphysiol.00932.2006. Epub 2006 Sep 28.


MicroRNAs (miRNAs) are a class of highly conserved, noncoding RNAs involved in posttranscriptional gene regulation. A small number of muscle-specific miRNAs have been identified and shown to have a role in myoblast proliferation and differentiation as well as embryonic muscle growth. The primary objective of the present study was to determine the expression level of the muscle-specific miRNAs in the soleus and plantaris muscles and whether their expression in the plantaris was altered in response to functional overload. Of the miRNAs examined, only miRNA-206 was differentially expressed between soleus and plantaris muscles, as reflected by the sevenfold higher expression in the soleus for both the primary miRNA (pri-miRNA) and mature miRNA (miR). Following 7 days of functional overload, transcript levels for both pri-miRNA-1-2 and pri-miRNA-133a-2 increased by approximately 2-fold, whereas pri-miRNA-206 levels were elevated 18.3-fold. In contrast, expression of miR-1 and miR-133a were downregulated by approximately 50% following overload. The discrepancy between pri-miRNA and miR expression following overload was not explained by a change in the expression of components of the miRNA biogenesis pathway, since Drosha and Exportin-5 transcript levels were significantly increased by 50% in response to functional overload, whereas Dicer expression remained unchanged. These results are the first to report alterations in expression of muscle-specific miRNAs in adult skeletal muscle and suggest miRNAs may have a role in the adaptation to functional overload.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Gene Expression Regulation
  • Hypertrophy / metabolism
  • Hypertrophy / pathology
  • Hypertrophy / physiopathology
  • Karyopherins / genetics
  • Karyopherins / metabolism
  • Male
  • Mice
  • Mice, Inbred C57BL
  • MicroRNAs / genetics
  • MicroRNAs / metabolism*
  • Muscle, Skeletal / metabolism*
  • Muscle, Skeletal / pathology*
  • Phenotype
  • Physical Conditioning, Animal / physiology
  • Ribonuclease III / genetics
  • Ribonuclease III / metabolism


  • Karyopherins
  • MicroRNAs
  • Mirn1 microRNA, mouse
  • Mirn133 microRNA, mouse
  • Xpo5 protein, mouse
  • Drosha protein, mouse
  • Ribonuclease III