Figure 5 of Kassen, Mol Vis 2008; 14:951-963.

Figure 5. Enhanced green fluorescent protein expression in the light-damaged Tg(ccnb1:EGFP)nt18 zebrafish retina. To initiate the regeneration response, dark-adapted adult Tg(ccnb1:EGFP)nt18 zebrafish were exposed to constant, high-intensity light to induce photoreceptor apoptosis. At 48 h of constant light exposure, enhanced green fluorescent protein (EGFP) is expressed in proliferating cell nuclear antigen (PCNA)-positive inner nuclear layer (INL) cells (A-C). EGFP expression is also observed in Müller glial cell processes (arrows). At 48 h of light damage, Müller glia are labeled with glutamine synthetase (GS; D, F). All the EGFP-positive cells co-label with glutamine synthetase expressing Müller glia (D-F). At 72 h of light damage, there are clusters of PCNA-positive neuronal progenitor cells associated with and migrating along Müller glia (G-I). These cells express EGFP at a high intensity. (J-L) A higher magnification of the migrating progenitor cells at 72 h of light damage reveals that EGFP is expressed throughout the glial cell (J, K). This is evident by labeling in the glial cell processes (arrows). There are multiple PCNA-positive progenitors that are also expressing EGFP (arrowheads). Abbreviations: GS represents glutamine synthetase; PCNA represents proliferating cell nuclear antigen; EGFP represents enhanced green fluorescent protein; ONL represents outer nuclear layer; INL represents inner nuclear layer; and GCL represents ganglion cell layer.