Perlecan morphants display a complex muscular dystrophy phenotype. (A, D, and F) Ultrastructural analysis of control skeletal muscle from a 5-dpf embryo. Parasagittal (A) and cross sections (D and F) of trunk muscle show typical muscular architecture with alignment of z bands, abundant glycogen (Gly) and mitochondria (Mi), and typical hexagonal arrays of thick and thin filaments (D). High magnification view shows thick filaments surrounded by six thin filaments (circle in F). In contrast, perlecan morphants induced by either translation-blocking (B) or splice-blocking (C, E, and G) morpholinos show disarray of muscular architecture with loss of filaments and irregular filaments traversing the sarcomeres at variable angles (arrows in B and C). Also notice the presence of areas with reduced thin filaments (asterisks in E) adjacent to more normal-appearing hexagonal structures (E). The sarcoplasmic reticulum (SR) appears to be normal (E). High magnification of the area labeled by the asterisk in E shows abnormal arrangement of thin and thick filaments (circle in G). Bars, 1 μm.