Fig. 8

hel mutant myocytes that are not subject to contractile signals in culture retain sarcomere organization. Dissociated blastomeres from individual WT (left) and hel mutant (right) embryos were cultured on laminin substrate to induce myogenesis for 5 days prior to fixation. Individual cultures were genotyped by PCR to confirm the identity of mutants and siblings. Immunofluorescent staining for myosin (green, A and B) and actin (red, C and D) demonstrated relatively normal sarcomere patterning in mutants as compared with WT (compare banding patterns in A with B and in C with D), with only a mild effect on sarcomere organization in mutants, although myosin A-band patterning with a standard sarcomere period could be readily discerned (B and D). There was little variability between cultures of the same time-point (n=64 total cultures examined).