Fig. 5

Bipolar cells in XBP1 fl/fl; Chx10-Cre retina extend dendrites into ONL and have more ectopic synapses than in age-matched WT. (a to d) Cryosections of retina labeled with antibodies against PKC-α (green), Ribeye (red) for XBP1 fl/fl (WT) at a 13 months and at c 21 months of age and XBP1 fl/fl; Chx10-cre positive (cKO; b and d) at 13 months of age. (b and d) XBP1 fl/fl; Chx10-Cre (cKO) at 13 months of age showing multiple extensions from bipolar cells into the outer nuclear layer (ONL; arrowheads) as well as the ectopic synapses outside the outer plexiform layer (OPL) in the ONL (arrows). c Similarly, WT retina at 21 months has multiple extensions from bipolar cells into ONL (arrowheads) and ectopic synapses in the ONL (arrows). e Graphs depict the number of ectopic synapses in the ONL. There are more than twice as many ectopic synapses in the XBP1 cKO (n = 4) than in WT (n = 5) at 13 months of age. Similarly, there are more than twice as many ectopic synapses in WT (n = 4) at age 22 months than at WT at age 13 months. f There are significantly more extensions from PKC-α positive bipolar cells into the ONL in XBP1 cKO compared to WT retina at 13 months. Similarly, there are significantly more extensions from PKC-α positive bipolar cells into the ONL in WT retina at 22 months of age compared to WT retina at 13 months of age. Scale bar = 20 μm. INL, inner nuclear layer. *, p < 0.05