Fig. 6.

Aberrant cell cycle reentry of cones in the p27 knockout (KO) retinas. a Immunofluorescence for Ki67 in the WT and KO retinas at P6 and later stages showing proliferating cells only in the KO retinas. Arrowheads indicate Ki67+ cells in the outer nuclear layer (ONL) of the KO retina at P12. INL, inner nuclear layer. b The ONL of the KO retina at P12 immunolabeled for Ki67 in combination with the photoreceptor marker recoverin, rod marker NR2E3, and cone marker S-opsin. Note colocalization of Ki67 with recoverin and S-opsin, but not with NR2E3 (arrowheads). c Double immunofluorescence for Ki67 and S-opsin in the KO retinas at P6 and later stages. Ki67+/S-opsin + cones are shown by arrowheads. d Quantification of Ki67+ cones in the KO retinas. Graph data represent the means ± SEM (n = 3 per stage). e Cones identified by S-opsin or M-opsin immunoreactivity express proliferation markers PCNA, phospho-Rb, and MCM6 in the KO retinas at P12. Scale bars = 20 μm