title: Clonal derivation of a rat muscle cell strain that forms contraction-competent myotubes.
abstract: A muscle cell strain capable of forming contracting myotubes was isolated from an established rat embryo cell line. The myogenic cells, termed rat myoblast omega or RMo cells, have a diploid complement of chromosomes (n = 42). In the presence of mitogen-containing growth medium, RMo cells proliferated with a cell generation time of about 12 hours. In mitogen-depleted medium, RMo cells withdrew from the cell cycle and formed myotubes that spontaneously contracted. Differentiated RMo cells produced creatine kinase isozymes in a ratio characteristic of skeletal muscle cells. RMo cells were easy to cultivate. Cells proliferated and differentiated equally well on gelatin-coated or noncoated culture dishes, at clonal or mass culture densities, and in all basal media tested. In most experiments, growth medium consisted of horse serum-containing medium supplemented with either chicken embryo extract or FGF activity; cells proliferated equally well in medium containing unsupplemented calf serum. RMo cells differentiated if growth medium was not replenished regularly. Alternatively, differentiation was induceable by incubation in mitogen-depleted medium consisting of basal medium supplemented either with 10(-6) M insulin, 0.5% serum, or 50% conditioned growth medium. RMo cells were competently transformed with cloned exogenous genes. Because it forms functional myofibrils, the RMo cell line constitutes a useful model system for studying the cell biology and biochemistry of proteins involved in contractile apparatus assembly and muscle disease.
authors.affiliation: Department of Biochemistry and Biophysics, Oregon State University, Corvallis 97331.
authors.forename: G F
authors.initials: GF
authors.lastname: Merrill
mesh_terms: D000818:Animals; D002455:Cell Division; D002460:Cell Line; D002461:Cell Line, Transformed; D002478:Cells, Cultured; D002999:Clone Cells; D004247:DNA / Q000032:analysis; D005786:Gene Expression Regulation; D009119:Muscle Contraction; D009124:Muscle Proteins / Q000235:genetics / Q000378:metabolism; D009132:Muscles / Q000166:cytology* / Q000378:metabolism / Q000502:physiology; D011003:Ploidies; D051381:Rats
chemical_list: D009124:Muscle Proteins; D004247:DNA