TUNEL-positive cells were observed in some cone and rod nuclei and BrdU incorporation were not changed in EYS-deficient retina. TUNEL staining and 1D4 immunostaining were carried out on retinal sections of 4, 8, and 14 mpf wild-type and EYS-deficient zebrafish retinas. BrdU-labeled nuclei were detected by immunofluorescence staining. (A) TUNEL staining of wild-type retina at 4 mpf. (B) TUNEL staining of EYS-deficient retina at 4 mpf. (C) TUNEL staining of wild-type retina at 14 mpf. (D) TUNEL staining of EYS-deficient retina at 14 mpf. (E) 1D4 immunostaining of wild-type retina. (F) 1D4 immunostaining of EYS-deficient retina. (G,H) Quantification of TUNEL-positive nuclei at 8 and 14 mpf, respectively. Error bars indicate s.e.m. (I,K) BrdU labeling at the ciliary margin of wild-type and EYS-deficient retina, respectively. (L,M) BrdU labeling at the central retina of wild-type and EYS-deficient retina, respectively. Note the presence of TUNEL-positive cone nuclei (asterisks in B), TUNEL-positive rod nuclei (asterisks in D), and 1D4 immunoreactive long double cone soma (asterisks in F) in EYS-deficient retinas. Also note absence of BrdU-labeled nuclei in the central retina of EYS-deficient animals. Scale bar: 20 µm.