CLONING AND EXPRESSION OF FROG RHODOPSIN CDNA

The cDNA encoding the putative rhodopsin of frog (Rana catesbeiana) wa s cloned and expressed in cultured cells. The deduced amino acid seque nce (354 residues) has more than 90% identity with the rhodopsins of t wo other frogs (Rana pipiens and Xenopus laevis) and 80% identity with other vertebrate rhodopsins. The isoelectric point calculated from th e sequence was about 8.2, which is intermediate between rhodopsins and the cone visual pigments of higher vertebrates. The cloned cDNA was e xpressed in cultured mammalian cells. The difference absorbance maximu m before and after photobleaching was about 500 nm, the same as that o bserved in the retina, demonstrating that the cloned cDNA does indeed encode functional rhodopsin.