The G protein messages in Octopus vulgaris photoreceptor were isolated and characterized with molecular biological techniques. Four classes of G protein α subunit cDNA were isolated from an octopus eye cDNA library: OvGαi, OvGαo, OvGαq and OvGαs. Northern blot analysis of octopus tissues showed abundant expression of OvGαq in the eye, and specific expression of OvGαo in neural tissues. OvGαi was expressed in all tissues studied. In situ hybridization revealed that OvGαq message was expressed in almost all photoreceptor cells. Based on these results, a possible phototransduction pathway in the octopus visual cells is discussed.
