Figure 6.

Egr-1 is sufficient to induce DARPP-32 expression in striatal primary neurons in vitro. Primary striatal neurons derived from E15–E17 embryos were transfected with empty vector (EV) GFP (a–c) or Egr-1–EGFP plasmid (d, e). After 24 h, cells were fixed with 4% paraformaldehyde and immunostained with α-GFP (green) and α-DARPP-32 (red). Single- and double-labeled cells were counted. Numbers were derived from 20 fields from two separate platings and transfections (***p < 0.001). Scale bars: a–f, 2.0 mm; d′–f′, 1.2 mm. Error bars indicate SEM.