Fig. 6.

In mice, CLDN19 is expressed in the retinal pigment epithelium (RPE), newborn retina, and overexpression of human CLDN19 mutants reduced the light response. a Quantitative-real-time RT-PCR (qRT²-PCR) detected endogenous CLDN19 messenger RNA (mRNA) in RPE and in the developing retina from postnatal days 0 to 21 (PN0 to PN21). Total RNA was isolated from the retinae, or RPE sheets, and pooled from 3 mice; n = 3 experiments. b Immunostaining of the neurosensory retina revealed endogenous claudin-19 initially present throughout the retina and later enriched in retinal ganglion cells (white arrowheads) on PN3. Claudin-19 was undetected on PN30 in the neurosensory retina. The inner plexiform layer was revealed by N-cadherin (NCAD; magenta) on PN3, and zonula occludens-1 (ZO-1; magenta) revealed the inner and outer retinal vascular beds (rightward arrows) on PN30. A vessel connects the two beds (leftward arrow). Scale bar, 20 µm. c RPE monolayer on P30 demonstrates that endogenous claudin-19 and ZO-1 co-localize in the tight junction. The XZ plane is at the top of the XY plane and the YZ plane is at the right. Blue arrowheads indicate location of the XY plane; cyan arrowheads indicate location of the XZ plane; magenta arrowheads indicate location of the YZ plane. Scale bar, 20 µm. d Adeno-associated virus (AAV) viral vectors that express exogenous CLDN19^WT, CLDN19^R81W, or CLDN19^G20D were injected into the subretinal space at PN0. Fundus (posterior retina) imaging was acquired on PN30, PN60, and PN90. Magenta arrows indicate hypo- or hyper- dense areas caused by the expression of mutated CLDN19; blue arrowheads show optic nerve head; blue arrow indicates a branch (or tributary) of the central ophthalmic artery (or vein). Scale bar, 500 µm. e Quantification of multifocal-electroretinogram P1 amplitudes at PN30, PN60, and PN90. Data were acquired from 9 different loci in 3 mice at each time point. Error bars ± SEM; ***P < 0.001