Functional recovery associated with dendrite regeneration in PVD neuron ofC. elegans

PVD neuron of C. elegans is a highly polarized cell with well-defined axonal, and dendritic compartments. PVD neuron operates in multiple sensory modalities controlling both nociceptive touch sensation and body posture. Although both axon and dendrites of this neuron show regeneration response following laser-assisted injury, it is rather unclear how the behavior associated with this neuron is affected by the loss of these structures. It is also unclear whether neurite regrowth would lead to functional restoration in these neurons. Upon axotomy, using a femtosecond laser, we saw that harsh touch response was specifically affected leaving the body posture unperturbed. Subsequently, recovery in the touch response is highly correlated to the axon regrowth, which was dependent on DLK-1 MAP Kinase. Dendrotomy of both major and minor primary dendrites affected the wavelength and amplitude of sinusoidal movement without any apparent effect on harsh touch response. We further correlated the recovery in posture behavior to the type of dendrite regeneration events. We found that dendrite regeneration with the fusion and reconnection between the proximal and distal branches of the injured dendrite corresponded to improved recovery of posture. Our data revealed that the axons and dendrites differentially regulate the functions of PVD neurons. It also revealed that dendrite and axon regeneration are both functionally and molecularly distinct.