Bovine fast-twitch myosin light chain 1: cloning and mRNA amount in muscle of cattle treated with clenbuterol.
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 This effect was lost when clenbuterol treatment was withdrawn for a 78-day period, during which time muscle growth in the treated animals stopped completely.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.
Smith
S B
SB
Department of Animal Science, Texas A&M University, College Station 77843, USA.
Davis
S K
SK
Wilson
J J
JJ
Stone
R T
RT
Wu
F Y
FY
Garcia
D K
DK
Lunt
D K
DK
Schiavetta
A M
AM
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002417:Cattle; D002976:Clenbuterol / Q000494:pharmacology*; D003001:Cloning, Molecular; D007527:Isoenzymes / Q000235:genetics* / Q000378:metabolism*; D008969:Molecular Sequence Data; D018656:Muscle Fibers, Fast-Twitch / Q000378:metabolism*; D009218:Myosins / Q000235:genetics* / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism*
D007527:Isoenzymes; D012333:RNA, Messenger; D009218:Myosins; D002976:Clenbuterol