Fig. 5. Decreased genesis of Type 2 cone bipolar, GABAergic and displaced amacrine cells. (A-H) Immunolabeling of retinal sections at P6 with bipolar subtype-specific markers reveals a dramatic drop in the genesis of CB cells immunoreactive for Vsx1 (A,E), recoverin (B,F, white arrowheads) and NK3R (C,G, white arrowheads) in Bhlhb5-null mice, whereas the total number of bipolar cells labeled by Chx10 is unchanged (D,H). (I,J,M,N) Anti-Prox1 labeling of retinal sections at P0 (I,M) and P6 (J,N) demonstrates the absence of displaced amacrine genesis in the GCL (white arrowheads) in Bhlhb5-null mice, whereas the Prox1⁺ horizontal cells (red arrowheads) in Bhlhb5-null mice are formed normally. (K,L,O,P) Anti-Pax6 (K,O) and anti-GAD65 (L,P) labeling also demonstrate a significant decrease in the genesis of amacrine cells in the INL. Scale bar: 100 µm.