Figure 3.

Phox2b^wt overexpression inhibits the proliferation of E7 sympathetic neurons, whereas Phox2b mutants Phox2b^R100L, Phox2b^R141G, Phox2b^K155X, Phox2b^676delG show no antiproliferative effect. Sympathetic neurons, transfected before plating with expression vectors for GFP, or cotransfected with Phox2b^wt or Phox2b^R100L, Phox2b^R141G, Phox2b^K155X and Phox2b^676delG, were labeled and immunostained for BrdU (red), GFP (green) and cell nuclei (DAPI) after 2 d in culture. Expression of Phox2b^wt, but not of Phox2b variants caused a decrease in the proportion of BrdU-labeled, GFP-positive transfected neurons. A, Effect of Phox2b^wt and Phox2b^R100L is shown. BrdU-labeled transfected neurons are indicated by arrowheads. Scale bar, 20 μm. B, The proportion of transfected GFP-positive neurons labeled by BrdU was determined after transfection with GFP only (control) or after cotransfection with Phox2b^wt or the Phox2b mutants indicated. Data are the mean ± SEM (n = 3, independent experiments). ***p < 0.001, significantly reduced compared with control.