Targeted deletion of Nmnat1 in mouse retina leads to early severe retinal dystrophy

Mutations in NMNAT1 can lead to a very severe type of retinal dystrophy, Leber congenital amaurosis, in human patients, characterized by infantile-onset or congenital retinal dystrophy and childhood blindness. The loss-of-function mouse models of Nmnat1 have not been well-established, since the complete knock-out (KO) of Nmnat1 in mice results in embryonic lethality. Here, we generated retina-specific KO by using the Crxpromotor-driving Cre combined with the flox allele. By a panel of histological and functional analyses, we found that Nmnat1 conditional KO (cKO) mice have early severe retinal dystrophy. Specifically, the photoreceptors of Nmnat1 cKO mice are almost diminished and the retinal functions also become completely abolished. Our results established a loss-of-function model for Nmnat1 in mice, which will be useful for studying the detailed functions of NMNAT1 in the retina.