The N-terminal region of CEP290 restores vision in a zebrafish model of human blindness

The gene coding for Centrosomal Protein 290 (CEP290), a large multi-domain protein, is the most frequently mutated gene underlying the non-syndromic blinding disorder Leber's congenital amaurosis (LCA). CEP290 has also been implicated in several cilia related syndromic disorders including Meckel-Gruber syndrome, Joubert syndrome, Senor-Loken syndrome and Bardet-Biedl Syndrome (BBS). In this study we characterize the developmental and functional roles of cep290 in the zebrafish. An antisense oligonucleotide (Morpholino, MO) designed to generate an altered cep290 splice product that models the most common LCA mutation was used for gene knockdown. We show that cep290 MO-injected embryos have reduced Kupffer's vesicle size and delays in melanosome transport, phenotypes that are also seen when bbs genes are knocked down in zebrafish. Consistent with roles in cilia function, the cep290 MO-injected embryos exhibited a curved body axis. Patients with LCA caused by mutations in CEP290 have reduced visual perception although they present with a fully laminated retina. Similarly, histological examination of retinas from cep290 MO-injected zebrafish revealed no gross lamination defects, yet the embryos had a statistically significant reduction in visual function. Finally, we demonstrate that the vision impairment caused by disruption of cep290 can be rescued by expressing only the N-terminal region of the human CEP290 protein. These data reveal that a specific region of the CEP290 protein is sufficient to restore visual function and this region may be a viable gene therapy target for LCA patients with mutations in CEP290.