(A) Immunohistochemical staining with cellular retinaldehyde-binding protein (CRALBP) antiserum (CRALBPas, magenta) and RPE65 (cyan) and glutamine synthetase (GS, yellow) as counterstain for RPE and Müller glia, respectively, on cryosections of adult retinas. In rlbp1a−/−, the layer containing RPE and outersegments is reduced in thickness and very disturbed, the white arrow indicates a remaining RPE65-positive cell. Bottom row showing CRALBPas channel, only. (B, C) Relative normalized expression of rlbp1a and rlbp1b in the eyes of the respective single-KO lines. Individual samples are shown with mean ± standard deviation (SD). (B) rlbp1a expression was reduced in rlbp1a−/− eyes [t(4) = 7.39, p = 0.003], while rlbp1b mRNA levels were comparable to wild type [t(4) = −0.06, p = 0.955]. (C) In rlbp1b−/−, rlbp1a expression was similar to wild type [t(4) = 0.849, p = 0.444], but rlbp1b mRNA levels were twofold reduced [t(4) = 2.84, p = 0.094]. Statistics: t-test comparing KO vs. wild type for each target with Benjamini–Hochberg correction for multiple testing. Significance: **p < 0.01. Abbreviations: double-knockout (dbKO), retinal pigment epithelium (RPE), outer segment (OS), outer nuclear layer (ONL), outer plexiform layer (OPL), and inner nuclear layer (INL). See Figure 1—source data 1 for expression data.
