Figure 1

Runx proteins control the diversification of sensory neurons. (a) Proprioceptive (TrkC⁺) and mechanoreceptive (TrkB⁺) DRG neurons are derived from the common precursors (TrkB⁺, TrkC⁺). During segregation of two complementary sensory populations, Runx3 represses trkB expression in TrkC⁺ neurons. (b) During early postnatal periods, TrkA⁺ DRG neurons differentiate into two nociceptive subpopulations; TrkA⁺ peptidergic neurons, and Ret⁺ non-peptidergic neurons that repress trkA. In Ret⁺ non-peptidergic neurons, Runx1 represses trkA and neuropeptide CGRP. Runx1 also activates a number of nociceptor-specific G protein coupled receptors, ATP channels, and TRPV channels. (c) G protein coupled receptor MrgA, B and C are under dynamic transcriptional regulation in DRG neurons. A carboxy-terminal VWRPY motif of Runx proteins is critical for binding to Groucho corepressor. Runx1, which lacks VWRPY, fails to repress MrgA, B and C in DRG neurons.