Résumé :
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Communication n° 252. We previously observed that cadherin-11, a type II cadherin, is expressed in growing motor and sensory axons in the mouse embryo. Here, we assessed its functional involvement in the regulation of axon elongation and fasciculation, by evaluating the activity of a specific cadherin-11 homophilic ligand, cad11-Fc (cadherin-11 extracellular region fused to Fc fragment of IgG), on the length and organization of motor axons outgrowing from embryonic ventral spinal cord explants. Cad11-Fc substrate enhanced axon growth and prevented interactions occurring between growing axons, providing evidences for a role of cadherin-11 in the control of growth cone progression. Comparison of cadherin-11 with N-cadherin, a type I cadherin concomitantly expressed by motor axons, revealed similarities in their functional properties, including the ability to reorganize the actin cytoskeleton through interactions with catenins. However, differences in their axon growth-promoting activity argue for subtle differences in their contributions to peripheral nerve elongation. We are currenty studying the mechanisms of action of these adhesion receptors during axonal elongation, focussing in particular on the dynamics of cadherins and associated proteins within the growth cone of spinal neurons in relation to their anchoring to the cytoskeleton. - Padilla F.; Broders F.; Nicolet M and Mège R.M. Mol. Cell. Neurosci. 1998, 11: 217-233. - Lambert M.; Padilla F. and Mège R.M. J. Cell Sci. 2000;113: 2207-2219. - Marthiens V.; Gavard J.; Padilla F.; Monnet C.; Castellani V.; Lambert M. and Mège R.M. Mol. Cell. Neurosci (In press).
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