Figure 9  Progressive Neuronal Specification Is Paralleled by a Developmental Shift in Response to ETS Transcription Factor Signaling
Schematic summary diagram illustrating the importance of temporally appropriate upregulation of transcription factor expression during specification of DRG neurons for late aspects of neuronal differentiation and circuit assembly.
(A–D) Expression of EWS-Pea3 from the endogenous Er81 locus can rescue anatomical defects observed in Er81−/− mice, and no change in expression of TrkC (green) or Calretinin (CR; grey) is observed in proprioceptive afferents (A, B, and D). In contrast, precocious ETS signaling leads to severe defects in the establishment of DRG neuronal projections accompanied by inappropriate gene expression changes (C; upregulation of CR (red) and downregulation of TrkC [grey]).
(E) Precocious ETS signaling (red) during progressive specification of proprioceptive sensory neurons leads to aberrant neuronal differentiation (red dashed line). In contrast, the isochronic, target-induced (green; peripheral signal) onset of ETS transcription factor signaling (black) induces appropriate terminal neuronal differentiation (blue).