Figure 1.

Cardiomyopathy is induced upon constitutive Mcl-1 deletion in cardiac and skeletal muscle. (A) Survival of muscle-specific Mcl-1-deleted mice. (**) P < 0.01 by log-rank test when compared with controls. (B) Constitutive Mcl-1 deletion in heart and skeletal muscle. All tissues were harvested at P1 and immunoblotted with MCL-1 and Actin. (C) Hematoxylin and eosin (H&E)-stained longitudinal sections of the heart indicate dilated cardiomyopathy and a loss of myofibrils. Connective tissue indicative of fibrosis stained blue with the Masson's trichrome stain. Hearts were harvested at P7. Magnifications: top, 2×; middle and bottom, 40×. (D) H&E-stained longitudinal sections of the tongue skeletal muscle indicate swollen fragmented fibers with hyaline necrosis. Magnification, 40×. (E) Cardiac-specific deletion of Mcl-1 induced cell death. Caspase-3- and Caspase-7-stained sections of the heart indicate positive cells in constitutively Mcl-1-deleted hearts (harvested at P7). Magnification, 40×.