Publication Date

Spring 2012

Degree Type


Degree Name

Master of Science (MS)


Biological Sciences


Miri VanHoven

Subject Areas

Genetics; Neurosciences; Developmental biology


Organisms receive, process, and respond to environmental cues via intricate neural circuits that form during development. Proper development of neuronal circuits is therefore critical to brain function. To form these circuits, a neuron must first extend its axons to the appropriate target. After reaching this target region, it must recognize its correct synaptic partners from multiple incorrect partners and form appropriate synapses. It is well understood how axons reach their target regions, but little is known about how neurons select the correct partners once there, a process called synaptic partner

recognition (SPR). Our work aims to elucidate the genetic programs that specify correct SPR in sensory circuits in the nematode Caenorhabditis elegans. We used the fluorescent trans-synaptic marker, Neuroligin 1-mediated GFP Reconstitution Across Synaptic Partners (NLG-1 GRASP). Using this marker, we discovered a role for an UNC-6/Netrin and UNC-40/DCC-mediated axon guidance pathway gene that functions in SPR. Interestingly, synaptic component localization in mutants of this gene is normal, indicating that the reduced SPR is not the result of a secondary defect in cell polarity or protein trafficking. Finally, we found that this gene functions in the UNC-6/Netrin and UNC-40/DCC SPR pathway previously described by our laboratory. Most remarkably, we found that the function of this gene in the SPR pathway is molecularly distinct from its previously characterized signaling pathways. The characterization of the novel role of this gene may give insights into the mechanism of sensory circuit formation.