GSBS Student Publications

Drosophila sensory neurons require Dscam for dendritic self-avoidance and proper dendritic field organization

Peter Soba, University of California
Sijun Zhu, University of California
Kazuo Emoto, University of California
Susan Younger, University of California
Shun-Jen Yang, University of Massachusetts Medical School
Hung-Hsiang Yu, University of Massachusetts Medical School
Tzumin Lee, University of Massachusetts Medical School
Lily Yeh Jan, University of California
Yuh-Nung Jan, University of California

Document Type Article

Abstract

A neuron's dendrites typically do not cross one another. This intrinsic self-avoidance mechanism ensures unambiguous processing of sensory or synaptic inputs. Moreover, some neurons respect the territory of others of the same type, a phenomenon known as tiling. Different types of neurons, however, often have overlapping dendritic fields. We found that Down's syndrome Cell Adhesion Molecule (Dscam) is required for dendritic self-avoidance of all four classes of Drosophila dendritic arborization (da) neurons. However, neighboring mutant class IV da neurons still exhibited tiling, suggesting that self-avoidance and tiling differ in their recognition and repulsion mechanisms. Introducing 1 of the 38,016 Dscam isoforms to da neurons in Dscam mutants was sufficient to significantly restore self-avoidance. Remarkably, expression of a common Dscam isoform in da neurons of different classes prevented their dendrites from sharing the same territory, suggesting that coexistence of dendritic fields of different neuronal classes requires divergent expression of Dscam isoforms.