Hughes, M.E., Bortnick, R., Tsubouchi, A., Bäumer, P., Kondo, M., Uemura, T., Schmucker, D. (2007). Homophilic Dscam interactions control complex dendrite morphogenesis.  Neuron 54(3): 417--427.

FBrf0200472

Research paper

Alternative splicing of the Drosophila gene Dscam results in up to 38,016 different receptor isoforms proposed to interact by isoform-specific homophilic binding. We report that Dscam controls cell-intrinsic aspects of dendrite guidance in all four classes of dendrite arborization (da) neurons. Loss of Dscam in single neurons causes a strong increase in self-crossing. Restriction of dendritic fields of neighboring class III neurons appeared intact in mutant neurons, suggesting that dendritic self-avoidance, but not heteroneuronal tiling, may depend on Dscam. Overexpression of the same Dscam isoforms in two da neurons with overlapping dendritic fields forced a spatial segregation of the two fields, supporting the model that dendritic branches of da neurons use isoform-specific homophilic interactions to ensure minimal overlap. Homophilic binding of the highly diverse extracellular domains of Dscam may therefore limit the use of the same "core" repulsion mechanism to cell-intrinsic interactions without interfering with heteroneuronal interactions.

PMC1963440 (PMC) (EuropePMC)