My lab research focuses on the molecular genetic mechanisms underlying the development and function of the nervous system, as well as those underlying adult axon regeneration. Our work is carried out in the nematode Caenorhabditis elegans, whose entre cell lineage and connectome are known. The transparency, defined anatomy, and rapid life cycle of this organism greatly facilitate the molecular genetic dissection in living animals at the subcellular resolution. Through forward genetic screening, in combination with multi-layered molecular and cellular manipulations, we have discovered key molecules that play conserved roles in axon pathfinding, synapse formation and function. Recently, we have established an adult axon regeneration model in C. elegans. Using an ultrafast laser-based microsurgery procedure to perform axotomy in C. elegans neurons (Yanik et al., Nature 2004), we have identified several pathways regulating the rate and accuracy of adult axon regeneration (Chen et al., 2011). Among them, we have investigated the mechanisms underlying the conserved MAPKKK DLK-1 in axon regeneration (Yan et al., Cell 2009; Ghosh-Roy et al., Dev Cel, 2012; Yan and Jin, Neuron, 2012). By advancing our knowledge of intrinsic signaling pathways, we hope to develop new strategies to enhance regrowth ability of injured axons.