Figure 6: β-catenin is dispensable for sensory axon regeneration.

(a) Representative immunoblots of DRG lysates from naive or injured mice. To induce injury, mice were subjected to sciatic nerve transection and DRGs were collected after 3 days. Actin antibodies were used as a loading control. Quantification of β-catenin level normalized against actin is presented (right). (b) Representative immunoblots from DRG neurons cultured for either 3 h or 3 days. For the 3 day cultures, neurons were grown in the presence of LY294002 (LY, 10 μM) or vehicle control (DMSO), as indicated. Actin antibodies were used as a loading control. Quantification of β-catenin level normalized against actin is presented (right). Error bars represent s.e.m. n.s., statistically insignificant difference, unpaired two-tailed Student’s t-test. (c) Representative blots for validating the efficacy of the siRNA against β-catenin (si-β-catenin) after in vivo electroporation into DRGs. Actin antibodies were used as a loading control. (d,e) L4 and L5 DRGs of an adult mouse were electroporated in vivo with either EGFP alone (control) or together with si-β-catenin, followed by sciatic nerve crush at 2 days after the electroporation. Axon regeneration was assessed by whole-mount analysis at 3 days after nerve injury. In vivo electroporation and investigation of axon regeneration were performed as depicted in Fig. 3a. Using whole-mount nerve segments, the lengths of all identifiable regenerating axons were measured from the crush site (arrowheads) to the distal axon tips. For quantification, lengths of a total of 145 axons from six control mice and 140 axons from six si-β-catenin-transfected mice were measured. Quantification (d) and representative images of axon regeneration (e) are shown. Scale bar, 500 μm. Error bars represent s.e.m. Original immunoblot images are shown in Supplementary Fig. S11.