Expression of lipoprotein lipase during differentiation of cultured L6 muscle cells.
The presence of lipoprotein lipase (LPL) in L6 muscle cells is equivocal. Analysis of a 21-day time course indicates that these cells express both LPL activity and mRNA. Lipase activity peaked at 4 days after plating and decreased to a nadir at day 21 after plating. Characterization of lipase activity at 4 and 19 days after plating, corresponding to myoblasts and myotubes, respectively, indicated that most of the enzyme activity had the properties of LPL, including an alkaline pH optimum, a serum requirement, and inhibition by NaCl. LPL mRNA expression peaked at 7 days after plating and fell slightly (24%) at day 21. The primary LPL mRNA species in these cells is 3.7 kb in length. Lipase activity and LPL mRNA were highly correlated during the nine course (r = +0.82), suggesting transcriptional regulation of the enzyme. These data clearly demonstrate that L6 cells express LPL during differentiation.
LaDu
M J
MJ
Exercise Research Division, College of Kinesiology, University of Illinois at Chicago 60680.
Palmer
W K
WK
D000818:Animals; D001345:Autoradiography; D015152:Blotting, Northern; D002454:Cell Differentiation; D002478:Cells, Cultured; D015342:DNA Probes; D008071:Lipoprotein Lipase / Q000235:genetics / Q000502:physiology*; D009132:Muscles / Q000166:cytology* / Q000201:enzymology*; D012313:RNA / Q000032:analysis; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics; D051381:Rats
D015342:DNA Probes; D012333:RNA, Messenger; D012313:RNA; D008071:Lipoprotein Lipase