Fig. 2. Wnt2b inhibits the differentiation of retinal progenitor cells. Retinal explants were prepared from E6 retinas electroporated with control (A,D,G,J), Wnt2b-expressing (B,E,H,K), or Delta1-expressing (C,F,I,L) provirus plasmids. They were cultured for 2 days, and sections were prepared and stained for molecular markers shown in the left column: visinin (green) and Hu (purple) in A-C, Pax6 (green) and Chx10 (purple) in D-F, glutamine synthetase (green) in G-I, and BrdU (green) and phosphorylated histone H3 (purple) in J-L. Note the decrease in the number of visinin- or Hu-expressing cells (B,C) and uniform co-expression of progenitor markers Pax6 and Chx10 (E,F) in Wnt2b- or Delta1-expressing retinal explants compared with the marker levels in the control explants. A number of cells incorporated BrdU in Wnt2b-expressing retinal explants (K), whereas few cells were positive for the proliferation markers in control (J) or Delta1-expressing (L) explants. (M) Percentage of BrdU+ cells in the explants expressing each construct (n=4). (N) Thickness of the retinal explants expressing each construct (n=4). ^**P<0.01, ^*P<0.05. Scale bars: 30 µm.