FUNCTIONALLY RELATED MOTOR-NEURON POOL AND MUSCLE SENSORY AFFERENT SUBTYPES DEFINED BY COORDINATE ETS GENE-EXPRESSION

Motor function depends on the formation of selective connections betwe en sensory and motor neurons and their muscle targets. The molecular b asis of the specificity inherent in this sensory-motor circuit remains unclear. We show that motor neuron pools and subsets of muscle sensor y afferents can be defined by the expression of ETS genes, notably PEA 3 and ER81. There is a matching in PEA3 and ER81 expression by functio nally interconnected sensory and motor neurons. ETS gene expression by motor and sensory neurons fails to occur after limb ablation, suggest ing that their expression is coordinated by signals from the periphery . ETS genes may therefore participate in the development of selective sensory-motor circuits in the spinal cord.