Light Stimulates a Transducin-Independent Increase of Cytoplasmic Ca super(2+) and Suppression of Current in Cones from the Zebrafish Mutant nof

Transducins couple visual pigments to cGMP hydrolysis, the only recognized phototransduction pathway in vertebrate photoreceptors. Here we describe a zebrafish mutant, no optokinetic response f super(w21) (nof), with a nonsense mutation in the gene encoding the alpha subunit of cone transducin. Reti...

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Bibliographic Details
Published in:The Journal of neuroscience 2003-01, Vol.23 (2), p.470-480
Main Authors: Brockerhoff, SE, Rieke, F, Matthews, H R, Taylor, M R, Kennedy, B, Ankoudinova, I, Niemi, G A, Tucker, CL, Xiao, Ming, Cilluffo, M C, Fain, G L, Hurley, J B
Format: Article
Language:English
Subjects:
Danio rerio
Freshwater
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Summary:Transducins couple visual pigments to cGMP hydrolysis, the only recognized phototransduction pathway in vertebrate photoreceptors. Here we describe a zebrafish mutant, no optokinetic response f super(w21) (nof), with a nonsense mutation in the gene encoding the alpha subunit of cone transducin. Retinal morphology and levels of phototransduction enzymes are normal in nof retinas, but cone transducin is undetectable. Dark current in nof cones is also normal, but it is insensitive to moderate intensity light. The nof cones do respond, however, to bright light. These responses are produced by a light-stimulated, but transducin-independent, release of Ca super(2+) into the cone cytoplasm. Thus, in addition to stimulating transducin, light also independently induces release of Ca super(2+) into the photoreceptor cytoplasm.
ISSN:0270-6474