To test the hypothesis that a temporal delay in the onset of transcriptional programs is crucial for the control of appropriate neuronal maturation, we studied the development of proprioceptive DRG neurons, since transcriptional effectors regulated by target-derived signals, as well as some of their downstream biological actions, have been identified for these neurons. Er81 controls proprioceptive afferent connectivity [14], and we therefore sought to identify an ETS transcriptional regulator that, when expressed over the normal time course of Er81 expression, is able to substitute for Er81 function within group Ia afferent sensory neurons. With this reference point, we then designed experiments to examine the effects of precocious post-mitotic expression of the same ETS transcription factor on sensory neuron differentiation.