Figure 5.

Growth inhibition and differential gene expression of cultured muscle cells lacking MNF. (a) Muscle cells isolated from 3-day-old wild-type (+/+), heterozygous (+/−), and Mnf null (−/−) neonates were cultured in growth medium (myoblasts) and differentiation medium (myotubes). Mnf mutant myoblasts are capable of forming differentiated myotubes under low serum conditions. (b) Cell proliferation assays were performed on muscle cells isolated from 3-day-old neonatal wild-type (+/+), Mnf-heterologous (+/−), and Mnf-null (−/−) mice (performed in triplicate). (c) Semiquantitative RT-PCR/Southern blot analysis of MNF isoforms and MyoD family members in wild-type myoblasts (MB) and myotubes (MT) compared with Mnf−/− myoblasts (MB) and myotubes (MT) (performed in quadruplicate).