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Fig. 9 High magnification images of retinal sections from adult Tg(nrd:egfp)/albino zebrafish over a time course of light treatment.
Sections were immunolabeled with EGFP (green) to visualize the nrd:egfp transgene and Zpr-3 (red) to visualize rod photoreceptors. (A) Prior to light treatment (0 hr), EGFP co-labels with Zpr-3 and is observed in rod photoreceptor soma, rod inner segments (RIS) and rod outer segments (ROS). (B) At 48 hours after light onset, the ROS and RIS are almost completely destroyed and only a few EGFP-positive cells remain in the ONL. (C) At 72 hours after light onset, newly-formed rod progenitor cells are present in the ONL. These could be readily discerned from existing rod photoreceptors due to their comparably weak expression of the transgene (inset shows new rod progenitor on the left). (D) At 96 hours after light onset, a greater number of new regenerated cells are present in the ONL, although it still somewhat disorganized. (E) At 7 days after light onset, newly differentiated rod photoreceptors appear more organized and greater in abundance. (F) At 11 days after light onset, EGFP is expressed in the newly formed rod photoreceptors and co-labels with Zpr-3-positive and newly-formed RIS and R0S. Scale bar: 50 microns (A–F).