%0 Journal Article
%T Rostral growth of commissural axons requires the cell adhesion molecule MDGA2
%A Pascal Joset
%A Andrin Wacker
%A R¨¦gis Babey
%A Esther A Ingold
%A Irwin Andermatt
%A Esther T Stoeckli
%A Matthias Gesemann
%J Neural Development
%D 2011
%I BioMed Central
%R 10.1186/1749-8104-6-22
%X MDGA2, a recently discovered cell adhesion molecule of the IgCAM superfamily, is highly expressed in dorsolaterally located (dI1) spinal interneurons. Functional studies inactivating MDGA2 by RNA interference (RNAi) or function-blocking antibodies demonstrate that either treatment results in a lack of commissural axon growth along the longitudinal axis. Moreover, results from RNAi experiments targeting the contralateral side together with binding studies suggest that homophilic MDGA2 interactions between ipsilaterally projecting axons and post-crossing commissural axons may be the basis of axonal growth along the longitudinal axis.Directed axonal growth of dorsal commissural interneurons requires an elaborate mixture of instructive (guidance) and permissive (outgrowth supporting) molecules. While Wnt and Sonic hedgehog (Shh) signalling pathways have been shown to specify the growth direction of post-crossing commissural axons, our study now provides evidence that homophilic MDGA2 interactions are essential for axonal extension along the longitudinal axis. Interestingly, so far each part of the complex axonal trajectory of commissural axons uses its own set of guidance and growth-promoting molecules, possibly explaining why such a high number of molecules influencing the growth pattern of commissural interneurons has been identified.For its function the mammalian central nervous system depends on precisely organized neuronal circuits. Synaptic connections between the cells of a circuit are established during development when axonal growth cones grow along specific pathways, reaching even very distant targets with exceptionally high precision. A combination of cell adhesion molecules, surface receptors and axon guidance molecules enables the growth cone to invade permissive areas and grow along specific molecular gradients [1,2]. Long distances are covered by splitting the entire trajectory into smaller segments with intermediate targets [3]. Such intermediate targets
%U http://www.neuraldevelopment.com/content/6/1/22