Fig. 1.

Delayed increase in the AChR ε-subunit mRNA by neuregulin in C2C12 myotubes. Stimulation of C2C12 myotubes was started by the addition of neuregulin (NRG) to a final concentration of 1 nm or an equal volume of vehicle (as a control). Cells were harvested for RNA isolation at the indicated times. Twenty micrograms of total RNA were resolved on a 1% agarose gel, transferred to nitrocellulose, and hybridized with [³²P]-labeled DNA probes specific for the ε-subunit. The loading was uniform as evidenced by an equal amount of GAPDH mRNA. A, Representative Northern blot radiograms.B, Histograms showing mean ± SD of two different samples. The mRNA levels at 0 min were considered to be 100%. **p < 0.01.