G protein alpha subunit genes in octopus photoreceptor cells

The G protein messages in Octopus vulgaris photoreceptor were isolated and characterized with molecular biological techniques. Four classes of G prote in a subunit cDNA were isolated from an octopus eye cDNA library: OvG alpha (l), OvG alpha(o), OvG alpha(q) and OvG alpha(s). Northern blot analysis of octopus tissues showed abundant expression of OvG alpha(q) in the eye, and specific expression of OvG alpha(o), in neural tissues. OvG alpha(i) was e xpressed in all tissues studied. In situ hybridization revealed that OvG al pha(q) message was expressed in almost all photoreceptor cells. Based on th ese results, a possible phototransduction pathway in the octopus visual cel ls is discussed.