Effect of misexpressed Tfap2b on the differentiation of different retinal cell types. (A-T) Sections from retinas electroporated with pCIG or pCIG-Tfap2b DNA were double-immunostained with an anti-GFP antibody and antibodies against the indicated cell type-specific markers. Misexpressed Tfap2b caused a significant increase of amacrine cells immunoreactive for Pax6, GLYT1, GABA, Gad65, Gad67, or calbindin (A-J, M, N), no change in the number of TH-immunoreactive amacrine cells or GS-immunoreactive Müller cells (K, L, S, T), and a significant decrease in the number of recoverin-immunoreactive photoreceptor cells (Q, R). Arrows point to representative colocalized cells and insets show corresponding outlined regions at a higher magnification. (U) Quantitation of GFP+ cells that become immunoreactive for various cell type-specific markers. Each histogram represents the mean ± SD for 3–5 retinas. More than 500 GFP+ cells were scored in each retina. Abbreviations: GCL, ganglion cell layer; INL, inner nuclear layer; IPL, inner plexiform layer; ONL, outer nuclear layer. Scale bar: A-J, M-P, S, T, 39.7 μm; K, L, 30.2 μm; Q, R, 23.8 μm.