Figure 7.

Nebulin deficiency reduces thin filament length. (A) Longitudinal sections of EDL and Sol muscles fluorescently labelled with phalloidin to stain actin filaments (top), Tmod (middle) to label the pointed end of actin filaments and α-actinin (bottom) to label the Z-disks. Calibration bar: 5 µm. (B) Measurements obtained from phalloidin-labeled sarcomeres show that thin filament length is significantly reduced in both muscle types. (C) The force-sarcomere length relation (Sol muscle) has a descending limb that is shifted to the left. (Note that the force is normalized to the maximal force at optimal length; for absolute force values, see Table 1.)