Effect of misexpressed Ptf1a on the formation of different retinal cell types. (A-X) Sections from retinas electroporated with pCIG or pCIG-Ptf1a DNA were double-immunostained with an anti-GFP antibody and antibodies against the indicated cell type-specific markers. Misexpressed Ptf1a resulted in overt increase in the number of amacrine cells immunoreactive for Pax6, GLYT1, calretinin, Tfap2b or TH (A-H, O, P), and smaller increase in the number of amacrine cells immunoreactive for GABA, Gad67, Gad65, or calbindin (I-N, Q, R). However, it suppressed the formation of bipolar cells immunoreactive for Chx10 (S, T), photoreceptor cells immunoreactive for recoverin (U, V), and Müller cells immunoreactive for GS (W, X). Arrows point to representative colocalized cells and insets show corresponding outlined regions at a higher magnification. (Y) Quantitation of GFP+ cells that become immunoreactive for a series of cell type-specific markers. Each histogram represents the mean ± SD for three 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-N, Q-T, W, X, 39.7 μm; O, P, 30.2 μm; U, V, 23.8 μm.