NCBE is expressed in bipolar cells and amacrine cells.
A, NCBE (green) is expressed in axon terminals (arrowheads) and somata (arrows) of type 1 and/or 2 OFF bipolar cells, labeled with NK3R (magenta). B, HCN4-labeled type 3A OFF bipolar cells (magenta) showed NCBE (green) distributed on dendrites (arrows) and axon terminals (arrowheads). C, D, PKARIIβ-labeled type 3B OFF bipolar cells (C, magenta) and CSEN-labeled type 4 OFF bipolar cells (D, magenta) with NCBE (green). Only proximal (arrows) but not distal dendrites (arrowheads) of type 3B OFF bipolar cells showed NCBE expression (C). Dendrites (arrows) and somata (arrowheads) of CSEN-labeled type 4 OFF bipolar cells were also positive for NCBE (D). E, Gα0-labeled dendrites (magenta, arrows) of ON bipolar cells did not show NCBE expression (green). However, some ON bipolar cell somata (arrowheads) were NCBE-positive. F, G, PKCα-labeled rod bipolar cells dendrites (magenta) showed no NCBE expression (F, green, arrows), whereas axon terminals strongly express NCBE (G, arrows). H, ZNP-1-labeled axon terminals (magenta) of type 6 ON bipolar cells showed NCBE expression (green, arrows). I, J, Retinal sections of NCBE WT mice were stained for NCBE (I, J, green) and ChAT (J, magenta). Merging the NCBE channel (I) with the ChAT channel (J) revealed that somata (arrows) and dendrites (arrowheads) of ChAT-labeled starburst amacrine cells express NCBE. K, L, NCBE- (K, L, green) and calretinin-labeled retinal sections (L, magenta). NCBE expression was found on calretinin-labeled dendrites (arrowheads) and somata (arrows) of amacrine cells in the retina. M, N, Calbindin-labeled horizontal cells (arrows) do not express NCBE, but calbindin-labeled somata (arrowheads) of amacrine cells do. All images represent projections (3 µm) of confocal stacks. Numbers 1–5 are labeling the IPL strata, scale bars (A–H) = 5 µm; (I–M) = 10 µm.