rolsAD328 mutant embryos display defects in the fusion of longitudinal visceral muscle founder cells but the migration of the founder cells is unaffected. The fusion-defective phenotype is most severe in the anterior part of the gut, which is covered mostly in just mononucleated muscles at the end of embryogenesis.
Mutant embryos show severe disruption of the somatic muscles and unfused myoblasts are seen. Myoblasts are closely apposed to each other and a morphologically indistinguishable from wild type in early stage 13 mutant embryos. However, by stage 14, precursor cells and myoblasts have lost their close alignment and have scattered throughout the mesoderm.
