Proliferation of Müller glia and rod precursor cells is not activated by light-induced damage, but by TNFα in gosh mutants at 3 wpf. Wild-type and gosh mutant retinas at 3 wpf are labeled with anti-PCNA antibody. Nuclei are stained with DAPI. The transgene Tg(gnat2:GFP) visualizes cone photoreceptors. In wild-type, undamaged controls, PCNA is expressed in the CMZ, and PCNA-positive cells are observed in the INL and ONL (A). However, the PCNA signal is almost absent in gosh mutant retinas (B). Treatment for 18 h under intense light damages photoreceptors (C,D). Wild-type sibling retinas showed an increase in the number of PCNA-positive cells located in the INL and ONL. On the other hand, the PCNA signal is still absent in gosh mutant retinas. TNFα intravitreal injections increase the number of PCNA-positive cells in wild-type sibling and gosh mutant retinas (E,F). Histogram depicting the number of PCNA-positive cells (G). Bars and lines indicate mean ± SEM, n: 6–11. Black and red bars, wild-type siblings and gosh mutants. Filled bars, no treatment; Open bars, photodamaged samples; Dotted bars, TNFα-injected sample (ns, p > 0.05; ∗p < 0.05; ∗∗p < 0.01).
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