Fluorescence image of myotubes at their (A) spreading ends and in their (B) central regions previously transfected with plasmids encoding different Z-band proteins: (a) myotilin, (b) telethonin, (c) FATZ, (d) cypher-1s, and (e) cypher-2s. The transfected myotubes were fixed and stained with sarcomeric alpha-actinin antibodies (a′–e′). Myotilin, FATZ and cypher are localized in the Z-bodies at the ends of myotubes, but telethonin is not. All the proteins are co-localized with alpha-actinin in the Z-bands of mature myofibrils in the central regions of the myotubes. (Bar = 5 μm.)