Figure 6.

Disruption of mitochondrial fusion by knockdown of Opa1 does not alter mitochondrial axonal transport. To assess whether disrupting mitochondrial fusion is itself sufficient to alter mitochondrial transport, we used siRNA to knock down Opa1 in DRG neurons. A, B, Embossed images of representative axons and the corresponding kymographs showing Opa1 knockdown (>90%) did not alter mitochondrial movement patterns. C, Mitochondrial size–frequency histogram showed that loss of Opa1 significantly decreased mitochondrial length similar to that seen in Mfn2^−/− cultures, reflective of decreased mitochondrial fusion. D, E, Pause times between anterograde or retrograde movements (D) and velocity of movements (E) were not altered by Opa1 knockdown (n is the number of axons from which kymographs were generated), unlike loss of Mfn2, indicating that loss of mitochondrial fusion alone does not alter mitochondrial transport.