Figure 2.

Quantification of mitochondrial characteristics in Opa1-deficient murine skeletal muscle myoblasts and Mfn2-deficient or Opa1-deficient murine skeletal muscle myotubes. Ultrastructure of A) control and B) Opa1-deficient primary skeletal muscle myoblasts. Quantification of C) mitochondrial area, D) cristae score, E) cristae number, F) cristae volume, and G) cristae surface area in control and Opa1-deficient primary skeletal muscle myoblasts. H) Percentage of tubular and lamellar cristae in control and Opa1-deficient primary skeletal muscle myoblasts. Ultrastructure of I,J) control and K,L) Mfn2-deficient primary skeletal muscle myotubes. Quantification of M) cristae number, N) cristae volume, O) mitochondrial area, P) number of mitochondria per μm², Q) circularity index, and R) cristae surface area in control and Mfn2-deficient skeletal muscle myotubes. Ultrastructure of S,T) control and U,V) Opa1-deficient primary skeletal muscle myotubes. W) Quantification of area, X) cristae number, Y) cristae area, Z) cristae score, and AA) cristae volume in control and Opa1-deficient skeletal muscle myotubes. Scale bars: A,B,I–L) 2 μm; S,U) 10 μm; T,V) 500 nm. Recombinant eGFP adenovirus (Ad-GFP) serves as a control while adenovirus-cre represents the experimental knockout. Opa1^fl/fl represents a control while Opa1^fl/fl-cre represents floxed deletion of Opa1. Blue arrows indicate mitochondria; orange arrows indicate cristae. Significance was determined using Welch’s t-test. **p < 0.01, ***p < 0.001, ****p < 0.0001.