PT - JOURNAL ARTICLE AU - Susan E. Brockerhoff AU - Fred Rieke AU - Hugh R. Matthews AU - Michael R. Taylor AU - Breandan Kennedy AU - Irina Ankoudinova AU - Gregory A. Niemi AU - Chandra L. Tucker AU - Ming Xiao AU - Marianne C. Cilluffo AU - Gordon L. Fain AU - James B. Hurley TI - Light Stimulates a Transducin-Independent Increase of Cytoplasmic Ca<sup>2+</sup> and Suppression of Current in Cones from the Zebrafish Mutant <em>nof</em> AID - 10.1523/JNEUROSCI.23-02-00470.2003 DP - 2003 Jan 15 TA - The Journal of Neuroscience PG - 470--480 VI - 23 IP - 2 4099 - http://www.jneurosci.org/content/23/2/470.short 4100 - http://www.jneurosci.org/content/23/2/470.full SO - J. Neurosci.2003 Jan 15; 23 AB - Transducins couple visual pigments to cGMP hydrolysis, the only recognized phototransduction pathway in vertebrate photoreceptors. Here we describe a zebrafish mutant, no optokinetic response fw21 (nof), with a nonsense mutation in the gene encoding the α 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. Thenof cones do respond, however, to bright light. These responses are produced by a light-stimulated, but transducin-independent, release of Ca2+ into the cone cytoplasm. Thus, in addition to stimulating transducin, light also independently induces release of Ca2+ into the photoreceptor cytoplasm.