A group led by Michael Hengartner, from the University of Zurich in Switzerland, cloned and characterised UNC-69, a previously known protein that had never been characterised. By studying mutants lacking unc-69 they show that the protein is widely expressed in the C.elegans nervous system and is required for normal axon development.
Hengartner and colleagues then show that UNC-69 physically interacts with another protein expressed in the nervous system, UNC-76. Through experiments on double mutant combinations, the authors show that the two proteins cooperate to regulate axon development. The authors also show that UNC-69 is needed for the formation or maintenance of new synapses.
It is known that UNC-76 binds to molecular 'motor' proteins called kinesins that transport vesicles along growing axons. Hengartner and colleagues propose that the UNC-69/UNC-76 complex may be implicated in vesicle trafficking, a process that is necessary for axon growth and new synapse formation.