Fig. 2

Conditional knockout of XBP1 in the retina through the use of Chx10-Cre does not affect retinal development. a Western blot of whole retina at P4 reveals a significant decrease is XBP1s protein in XBP1 f/f; Chx10-cre (cKO) retina, compared to WT. b Cryosection of P4 retina after alkaline phosphatase staining (blue, arrow) reveals Cre-recombinase activity in all retinal layers, but not all retinal cells, at this age. c Cryosection through P15 retina counterstained with DAPI demonstrating that the Chx10 GFP-Cre recombinase fusion protein is localized to bipolar cells at this age (arrowhead). d PCR with primers specific for the non-recombined XBP1 floxed (fl) and recombined (Δ) XBP1 alleles reveals that Cre-mediated recombination is specific to retina. e Graph of measurements of retinal layers at P15 showing no statistically significant differences in the outer nuclear layer (ONL), inner nuclear layer (INL), and inner plexiform layer (IPL) between WT (n = 5) and XBP1 cKO (n = 7) at this age. f Cryosection through central retina of an XBP1 cKO mouse labeled with antibodies against the RGC marker Brn3a (red) and counterstained with DAPI (blue) at P15. Inset is higher magnification view of the boxed area. Lower panel is the same section showing the GFP-cre fusion protein is present in bipolar cells throughout retina at this age. g The number of Brn3a-positive and Brn3a-negative cells within the ganglion cell layer (GCL) at P15 are not statistically different between WT (n = 5) and XBP1 cKO (n = 6). OD, optic disk. Scale bar = 200 μm in B, 50 μm in C, 350 μm in F, and 150 μm in F, inset