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. Author manuscript; available in PMC: 2015 Aug 18.
Published in final edited form as: Dev Biol. 2009 Nov 13;337(2):396–404. doi: 10.1016/j.ydbio.2009.11.015

Fig. 5.

Fig. 5

Foxj3 is essential for the determination of adult myofiber identity. (A) Metachromatic ATPase staining of EDL and soleus skeletal muscles of WT and Foxj3m/m mice. Foxj3m/m muscles have decreased numbers of Type 1 oxidative slow-twitch fibers and increased numbers of Type IIa/b fast twitch fibers. (B) Quantitation of Type 1 fibers in wild type and Foxj3m/m EDL muscles (n=4 separate muscles; 3 littermate pairs; *p<0.05) reveals decreased Type 1 fibers compared to WT control. (C) Quantitation of Type 1 fibers in wild type and Foxj3m/m soleus muscles (n=4 separate muscles; 3 littermate pairs; *p<0.05) reveals decreased Type 1 fibers compared to WT control. (D and E) Isolated wild type and Foxj3m/m EDL (D) and soleus (E) skeletal muscle stress-frequency responses. Both the EDL and soleus muscles of the Foxj3 mutant mice showed a right shift in the stress–frequency relationship compared to their wild type littermates (n=4 separate muscles; 3 littermate pairs; *p<0.05).