Light-elicited and age-dependent accumulation of apoptotic nuclei selectively in photoreceptors is substantially reduced in RanBP2 haploinsufficient mice. TUNEL staining reflecting the nucleosomal DNA fragmentation of nuclei of photoreceptors show comparable cell-death between 12-week old RanBP2+/+ and RanBP2+/− mice (a, b), while there is a substantial increase in apoptosis in 24-week old RanBP2+/+, but not RanBP2+/− mice (c-f). a, b, e and f are high power micrographs of the central region of the retina. c and d are low power micrographs of the whole retina attached to the eyecup (white arrows point to the outer nuclear layer of photoreceptors). Legend: ONL, outer nuclear layer (nuclei of photoreceptors); INL, inner outer nuclear layer (nuclei of second-order neurons); GC, ganglion cell layer. Scale bar in a, b, e and f, 100 μm; scale bar in c and d, 500 μm.