An Extracellular Adhesion Molecule Complex Patterns Dendritic Branching and Morphogenesis

• Published in: Cell 2013-10, Vol.155 (2), p.296-307
• Main Authors: Dong, Xintong, Liu, Oliver W., Howell, Audrey S., Shen, Kang
• Format: Article
• Language: English
• Subjects: adhesion; Animals; Caenorhabditis elegans; Caenorhabditis elegans - metabolism; Caenorhabditis elegans Proteins - genetics; Caenorhabditis elegans Proteins - metabolism; complexing; dendrites; Dendrites - metabolism; Fibronectins - metabolism; in vitro studies; ligands; Membrane Proteins - genetics; Membrane Proteins - metabolism; morphogenesis; mutation; Neural Cell Adhesion Molecules - genetics; Neural Cell Adhesion Molecules - metabolism; Neurogenesis; Phylogeny; receptors; sensory neurons
• ISSN: 0092-8674; 1097-4172
• DOI: 10.1016/j.cell.2013.08.059

Robust dendrite morphogenesis is a critical step in the development of reproducible neural circuits. However, little is known about the extracellular cues that pattern complex dendrite morphologies. In the model nematode Caenorhabditis elegans, the sensory neuron PVD establishes stereotypical, highly branched dendrite morphology. Here, we report the identification of a tripartite ligand-receptor complex of membrane adhesion molecules that is both necessary and sufficient to instruct spatially restricted growth and branching of PVD dendrites. The ligand complex SAX-7/L1CAM and MNR-1 function at defined locations in the surrounding hypodermal tissue, whereas DMA-1 acts as the cognate receptor on PVD. Mutations in this complex lead to dramatic defects in the formation, stabilization, and organization of the dendritic arbor. Ectopic expression of SAX-7 and MNR-1 generates a predictable, unnaturally patterned dendritic tree in a DMA-1-dependent manner. Both in vivo and in vitro experiments indicate that all three molecules are needed for interaction. [Display omitted] •SAX-7/L1CAM acts as a spatially patterned guidance cue in the hypodermis•SAX-7/L1CAM and MNR-1 guide the outgrowth, branching, and stability of dendrites•DMA-1 acts as the neuronal receptor for SAX-7 and MNR-1 A receptor-ligand complex located at the membrane instructs the spatial morphogenesis of dendrites.