FUNCTIONAL-CHARACTERIZATION OF VISUAL AND NONVISUAL PIGMENTS OF AMERICAN CHAMELEON (ANOLIS-CAROLINENSIS)

Using only 11-cis 3, 4-dehydroretinal as a chromophore in the pure-con e retina, American chameleon (Anolis carolinensis) detects a wide rang e of color from ultraviolet (UV) to infrared. We previously characteri zed its visual opsin genes sws1(Ac), sws2(Ac), rh1(Ac), rh2(Ac), and l ws(Ac) that encode SWS1(Ac), SWS2(Ac), RH1(Ac), RH2(Ac), and LWSAc ops ins, respectively, and the pineal gland-specific opsin (P-Ac) gene. He re we present the light absorption profiles of the visual pigments obt ained by expressing these opsins and reconstituting them with 11-cis r etinal using the COS1 cell cDNA expression system. The purified SWS1(A c), SWS2(Ac), RH1(Ac), RH2(Ac), LWSAc, and P-Ac pigments have the wave lengths of maximal absorption at 358, 437, 491, 495, 560, and 482 mn, respectively. SWS1(Ac) is the first vertebrate UV opsin whose spectral sensitivity has been directly evaluated. RH1 pigments, orthologous to the rod pigments of other vertebrates, are sensitive to hydroxylamine in the dark, exhibiting a cone pigment-like characteristic, probably reflecting their adaptation to the pure cone retina. Interestingly, th e blue-sensitive SWS2(Ac) pigment shows an exceptionally low level of sensitivity to hydroxylamine, possessing a rod pigment-like characteri stic. (C) 1997 Elsevier Science Ltd.