Figure 5.

Continually proliferative cells in regions of retinal dysplasia in ptc2^−/− mutants. A BrdU/EdU double-labeling experiment was performed on wild-type gfap:GFP (B) and ptc2^−/−;gfap:GFP mutant retinas (C, D, D1–3). The fish were exposed to BrdU for 8 hours at 40 dpf, returned to their tanks for 2 days, injected with EdU at 42 dpf (6 weeks), and fixed for BrdU and EdU immunohistochemistry and detection (A). In wild-type retinas, cells that were proliferative at the time of fixation (EdU⁺) were mostly confined to the CMZ, whereas cells that were proliferative 2 days before fixation (BrdU⁺) had incorporated into the retina. In addition, a few GFP⁺ Müller glia were also either BrdU⁺ or EdU⁺ (B). In ptc2^−/−;gfap:GFP retinas, in addition to BrdU⁺/GFP⁺ or EdU⁺/GFP⁺ Müller glia, BrdU⁺/EdU⁺ double-labeled cells were detected in the peripheral retina, and these did not express GFP (C, and white arrows in high magnification of boxed region in D and in D1–3, n = 3/3). Scale bars: (B, C) 100 μm; (D, D1–3) 20 μm.