The ubiquitin ligase PHR promotes directional regrowth of spinal zebrafish axons

After a spinal cord injury, axons need to regrow robustly and directionally to reconnect. This study uses zebrafish, which have a high capacity for spinal axon regrowth, to understand how this process works. The researchers found that a protein called PHR is important for directing regrowing axons along the correct path after injury. Without PHR, the axons tend to grow in the wrong direction. PHR appears to work by helping to correct misdirected sprouts that initially grow in the wrong direction after the axon is cut. This correction process involves other proteins like cyfip2 and JNK.

• 1
  PHR directs regrowing axons along the pre-lesional trajectory and across the transection site in zebrafish spinal axons.
• 2
  PHR is required for directional regrowth across the transection site and along the pre-lesional trajectory.
• 3
  PHR controls directional Mauthner axonal regrowth through cyfip2- and JNK-dependent pathways.