Figure 6. Rosette formations in the photoreceptor layer of P20 animals heterozygous or homozygous for the Rosa26-floxSTOP/SRF-VP16 transgene. Histological sections are provided displaying rosette formations in the photoreceptor layers of Rosa26- floxSTOP/SRF-VP16 heterozygous or homozygous P20 animals. A-C: Hematoxylin and eosin–stained sections are shown of retinas obtained from wild-type, heterozygous, and homozygous P20 animals. Scale bar represents 200 μm. A: Normal wild-type retina is displayed and compared to those of heterozygous (B) and homozygous (C) transgenic animals, showing the localization of rosette formation around the vicinity of the optic nerve. D-F: Magnifications are shown of regions of the retinas displaying normal (D) or dyslaminated (E, F) retinal layers. Normal mislamination in wild-type retinas (D) with the ganglion cell layer (GCL), inner plexiform layer (IPL), inner nuclear layer (INL), outer nuclear layer (ONL), inner and outer segments (IS/OS), and retinal pigment epithelium (RPE). Rosette formations to a varying extents are shown in heterozygous (E) and homozygous (F) P20 retinas. Scale bars represent 50 μm. G: Quantification of rosette formation is shown. Retinas displaying rosette formations were categorized as positive for rosette formation. Eighty-seven percent of the heterozygous animals showed rosette formation, while 100% homozygous animals displayed rosette structures.