Fig. 2.

Abnormalities of Stac3 KO mice. (A) Complete paralysis, wrist drop, and abnormally rounded lunar appearance of a newborn Stac3 KO mouse. (B) Alveoli of KO lungs are not inflated, as shown by Masson’s trichrome staining. (C) Whole-mount E18.5 skeletons prepared with alcian blue, a cartilage stain, and alizarin red S, a bone stain, show numerous abnormalities in KOs, including abnormal spinal curvature, growth defects in costal cartilages, and decreased bone formation at muscle insertion sites. (D) H&E sagittal paraffin sections of E16.5 heads show decreased muscle mass of the tongue and abnormal clustering of nuclei in KOs. KO fibers also have fewer observable striations, and most have a vacuolated appearance. (E) Electron microscopy of E15.5 tongues shows that sarcomeres are present in KO fibers as seen here but overall, sarcomeres appear more disorganized (Fig. S7). (Scale bars, 1 μm.)