Bovine fast-twitch myosin light chain 1: cloning and mRNA amount in muscle of cattle treated with clenbuterol. Academic Article uri icon


  • The cDNA clone encoding the fast-twitch isoform of myosin light chain 1 (MLC-1f) was isolated from bovine longissimus dorsi muscle and sequenced in M13 and pUC8. An 0.8-kb subclone, produced by digestion of the cDNA with EcoRI, contained the portion of the molecule common to MLC-1f and MLC-3f. The cDNA in pUC8 contained an additional 81 bp upstream of the EcoR I digestion site, which was unique to MLC-1f. The cDNA clone was used to measure MLC-1f mRNA in longissimus dorsi muscle of cattle chronically administered the beta-adrenergic agonist clenbuterol. Treatment with clenbuterol for 50 days increased succinic dehydrogenase negative (type IIB) and positive (types I and IIA) myofiber cross-sectional areas by 25%. After the 50-day treatment period, the amount of MLC-1f mRNA was 90% greater in longissimus dorsi muscle of treated animals than in the initial group. This effect was lost when clenbuterol treatment was withdrawn for a 78-day period, during which time muscle growth in the treated animals stopped completely. We conclude that we have cloned the bovine cDNA for MLC-1f, which has provided additional evidence that beta-adrenergic agonists increase myofibrillar gene expression.

published proceedings

  • Am J Physiol

author list (cited authors)

  • Smith, S. B., Davis, S. K., Wilson, J. J., Stone, R. T., Wu, F. Y., Garcia, D. K., Lunt, D. K., & Schiavetta, A. M.

citation count

  • 14

complete list of authors

  • Smith, SB||Davis, SK||Wilson, JJ||Stone, RT||Wu, FY||Garcia, DK||Lunt, DK||Schiavetta, AM

publication date

  • May 1995