Figure 8.

Expression of the dominant-negative mutant Rac1N17 accelerates maturation of sarcomeres. QMb-LA29 transiently transfected with expression vectors encoding for β-galactosidase (A and B) and the myc epitope–tagged Rac1N17 (C and D) were allowed to differentiate for 2 d at 41°C in DM and then processed for immunofluorescence. Confocal micrographs of myotubes double labeled with antibodies to myosin (A and C) and either β-galactosidase (B) or the myc epitope (D) show that the cross-striations due to the organization of the A bands are more prominent in myotubes expressing Rac1N17 than in controls expressing β-galactosidase. Bar, 25 μm.