Fragile axons forge the path to gene discovery: a MAP kinase pathway regulates axon regeneration

Abstract

The nematode Caenorhabditis elegans is emerging as a promising model for studying the molecular control of axon regeneration. A forward genetic screen identified the DLK-1 (dual leucine zipper-bearing kinase 1) MAP (mitogen-activated protein) kinase pathway as a positive regulator of growth cone formation during axon regeneration. Although DLK-1 pathway mutant animals display a dramatic defect in regeneration, their axons have no apparent defects in initial outgrowth. The DLK-1 pathway also plays a role in synaptogenesis, but this role appears to be separate from its function in regeneration. Understanding how the DLK-1 pathway acts in development, plasticity, and regeneration may shed light on the evolution of mechanisms regulating axon regeneration.