Previous reports of a loss of two other Vps proteins in zebrafish, Vps18 and Vps39, showed deleterious effects on RPE and photoreceptor viability.
35,36 To determine whether loss of Vps11 resulted in retinal pathology, we examined retinas from wild-type and
platinum mutants at 5 dpf for the presence of proteins associated with specific retinal cell types, the total number of retinal nuclei per nuclear layer and overall eye size. Immunolocalization of Pax6a revealed that both the wild-type (
Fig. 6A) and
platinum mutant retinas (
Fig. 6B) contained amacrine and ganglion cells at 5 dpf. The
platinum mutant retinas also exhibited persistent Pax6a expression in the retinal progenitors located in the ciliary marginal zone (
Fig. 6B). Immunolocalization of glutamine synthetase revealed that the
platinum mutant retinas contained a normal contingent of Müller glial cells (
Fig. 6D). However, many of the Müller glial cell bodies were hypertrophied (
Fig. 6D). Immunolocalization of zpr3 (
Figs. 6E,
6F) and zpr1 (
Figs. 6G,
6H) revealed the presence of both rod and double cone photoreceptors, respectively, in the
platinum mutant retinas. Although the
platinum mutants were slightly microphthalmic at 5 dpf (94% of wild-type;
n = 5;
Supplementary Fig. S2), the reduction in eye size was not significant (
P = 0.3), nor was there a significant difference in the total number of nuclei present in each nuclear layer (Supplementary Fig. S2D). However, pyknotic nuclei were observed in each retinal layer in the
platinum mutants, concentrated primarily near the margins (
Fig. 6J; Supplementary Fig. S2). Co-labeling with zpr3 revealed an average of 17 pyknotic rod nuclei per retinal section in the
platinum mutant retinas (
Fig. 6J; Supplementary Fig. S2). Thus, even though retinal cell types formed normally in the
platinum mutants, retinal disease was present at 5 dpf.