Fig. 7. Detachment of myofilaments at the MTJ. Electron micrographs of tibialis (A-E), diaphragm (F-J) and soleus (K,L) muscles collected from 1-month-old (A-C,H,I) and 6-month-old (D-G,J-L) wild-type (WT) and Tln1 mutant (MT) mice. In wild-type mice, myofilaments connected to junctional electron-dense plaques are visible (arrowheads in A,D,F). In 1-month-old Tln1HSA-CREko mice, most MTJs were intact (B), but detachment of myofibers from MTJs was occasionally observed (C). In 6-month-old mutant animals, detachment of the myofibers was observed very frequently (E). Necrotic material was present where myofibers detached (asterisks in C,E,G). The thickness of the junctional plaque was reduced, and gaps were present where myofilaments failed to attach (arrows in G). Degeneration (I) and accumulation (K,L) of mitochondria were observed. Necrotic areas were observed in mutant fibers (J,K, asterisk) next to abnormal myofilaments (K, arrows). Scale bars: 3 µm in A-E,H,I; 1 µm in F,G; 10 µm in J-L.