Fig. 6.

Loss of PRDM8 alters AC-subtype identity. Confocal micrographs of retinal cryosections from adult Prdm8^EGFP/EGFP mice and WT littermates stained for AC markers. (A and B) Fewer GAD65⁺ ACs in the INL and decreased GAD65 IPL staining were present in the Prdm8^EGFP/EGFP retina, specifically of the middle and innermost GAD65⁺ bands of the IPL. (A–A″) PRKCA⁺ ACs colocalized with a subset of weakly positive GAD65⁺ cells in WT retina (arrows). (B–B″) In the Prdm8^EGFP/EGFP retina, PRKCA⁺ AC numbers were significantly increased; some PRKCA⁺ cells were GAD65⁺ (arrows), whereas others expressed very low intensity or no GAD65 (arrowheads). (C) CHAT⁺ cholinergic AC bodies and their processes did not coexpress PRKCA in WT retina. (D) In Prdm8^EGFP/EGFP retina, both CHAT⁺ and PRKCA⁺ ACs were increased in number, but the two populations remained distinct. (E–F′) VGLUT1 labels axon terminals of BP cells, and calretinin labels a subset of ACs, which together help to define the five sublaminae of the IPL. (E and F) Lamination was maintained in Prdm8^EGFP/EGFP retina, but the density of VGLUT1 staining in each sublamina was reduced, and the layers appeared to be thinner. (E′ and F′) Enlargement of IPL areas described in E and F.