Specificity of Monosynaptic Sensory-Motor Connections Imposed by Repellent Sema3E-PlexinD1 Signaling

• DOI: 10.1016/j.celrep.2013.10.005
• Publication Date: 2013-11-07T12:01:33Z
• Authors: Kaori Fukuhara; Fumiyasu Imai; David R. Ladle; Kei-ichi Katayama; Jennifer R. Leslie; Silvia Arber; Thomas M. Jessell; Yutaka Yoshida
• Keywords: Motor Neurons; 0303 health sciences; Membrane Glycoproteins; Sensory Receptor Cells; QH301-705.5; Intracellular Signaling Peptides and Proteins; Membrane Proteins; Nerve Tissue Proteins; Semaphorins; Substrate Specificity; Cytoskeletal Proteins; Mice; 03 medical and health sciences; Neural Pathways; Animals; Biology (General); Glycoproteins; Signal Transduction

In mammalian spinal cord, group Ia proprioceptive afferents form selective monosynaptic connections with a select group of motor pool targets. The extent to which sensory recognition of motor neurons contributes to the selectivity of sensory-motor connections remains unclear. We show here that proprioceptive sensory afferents that express PlexinD1 avoid forming monosynaptic connections with neurons in Sema3E(+) motor pools yet are able to form direct connections with neurons in Sema3E(off) motor pools. Anatomical and electrophysiological analysis of mice in which Sema3E-PlexinD1 signaling has been deregulated or inactivated genetically reveals that repellent signaling underlies aspects of the specificity of monosynaptic sensory-motor connectivity in these reflex arcs. A semaphorin-based system of motor neuron recognition and repulsion therefore contributes to the formation of specific sensory-motor connections in mammalian spinal cord.