biostudies-literatureUnknown98(3)von Lintig JVisual pigments (rhodopsins) are composed of a chromophore (vitamin A derivative) bound to a protein moiety embedded in the retinal membranes. Animals cannot synthesize the visual chromophore de novo but rely on the uptake of carotenoids, from which vitamin A is formed enzymatically by oxidative cleavage. Despite its importance, the enzyme catalyzing the key step in vitamin A formation resisted molecular analyses until recently, when the successful cloning of a cDNA encoding an enzyme with beta,beta-carotene-15,15'-dioxygenase activity from Drosophila was reported. To prove its identity with the key enzyme for vitamin A formation in vivo, we analyzed the blind Drosophila mutant ninaB. In two independent ninaB alleles, we found mutations in the gene encoding the beta,beta-carotene-15,15'-dioxygenase. These mutations lead to a defect in vitamin A formation and are responsible for blindness of these flies.Proceedings of the National Academy of Sciences of the United States of America1130-5https://www.ebi.ac.uk/biostudies/studies/S-EPMC14720biostudies-literatureAnalysis of the blind Drosophila mutant ninaB identifies the gene encoding the key enzyme for vitamin A formation invivo.PMC14720Kiefer CDreher AWernet MFVogt Kvon Lintig JfalseAnalysis of the blind Drosophila mutant ninaB identifies the gene encoding the key enzyme for vitamin A formation invivo.Visual pigments (rhodopsins) are composed of a chromophore (vitamin A derivative) bound to a protein moiety embedded in the retinal membranes. Animals cannot synthesize the visual chromophore de novo but rely on the uptake of carotenoids, from which vitamin A is formed enzymatically by oxidative cleavage. Despite its importance, the enzyme catalyzing the key step in vitamin A formation resisted molecular analyses until recently, when the successful cloning of a cDNA encoding an enzyme with beta,beta-carotene-15,15'-dioxygenase activity from Drosophila was reported. To prove its identity with the key enzyme for vitamin A formation in vivo, we analyzed the blind Drosophila mutant ninaB. In two independent ninaB alleles, we found mutations in the gene encoding the beta,beta-carotene-15,15'-dioxygenase. These mutations lead to a defect in vitamin A formation and are responsible for blindness of these flies.2001-01-01T00:00:00Z2001 Jan2025-04-26T23:35:55.942Z2019-03-26T23:45:17ZS-EPMC147201115860610.1073/pnas.98.3.1130