Pineal Opsin: A Nonvisual Opsin Expressed in Chick Pineal

• Published in: Science (American Association for the Advancement of Science) Vol. 267; no. 5203; pp. 1502 - 1506
• Main Authors: Max, Marianna, McKinnon, Peter J., Seidenman, Kenneth J., Barrett, R. Keith, Applebury, Meredithe L., Takahashi, Joseph S., Margolskee, Robert F.
• Format: Journal Article
• Language: English
• Published: Washington, DC American Society for the Advancement of Science 10-03-1995; American Association for the Advancement of Science; The American Association for the Advancement of Science
• Subjects: Amino Acid Sequence; Amino acids; Animals; Avian Proteins; Base Sequence; Biological and medical sciences; Biological Evolution; Brain Chemistry; Cell culture techniques; Chickens; Cloning, Molecular; Coding; Complementary DNA; Fundamental and applied biological sciences. Psychology; Hypothalamus. Hypophysis. Epiphysis. Urophysis; Introns; Libraries; Light; Molecular Sequence Data; Morphology. Functional localizations; Nerve Tissue Proteins - analysis; Nerve Tissue Proteins - chemistry; Nerve Tissue Proteins - genetics; Nerve Tissue Proteins - physiology; Opsins; Photoreceptors; Physiological aspects; Pineal gland; Pineal Gland - chemistry; Polymerase chain reaction; Protein Structure, Secondary; Proteins; Retina; Retina - chemistry; RNA; RNA, Messenger - analysis; Rod Opsins - analysis; Rod Opsins - chemistry; Rod Opsins - genetics; Rod Opsins - physiology; Sequence Homology, Amino Acid; Transcripts (Written Records); Vertebrates; Vertebrates: endocrinology; Vertebrata; Endocrine gland; Molecular structure; Pigments; Pineal body; Opsin; Chicken; Aves; Gene expression; Aminoacid sequence
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.7878470

Pineal opsin (P-opsin), an opsin from chick that is highly expressed in pineal but is not detectable in retina, was cloned by the polymerase chain reaction. It is likely that the P-opsin lineage diverged from the retinal opsins early in opsin evolution. The amino acid sequence of P-opsin is 42 to 46 percent identical to that of the retinal opsins. P-opsin is a seven-membrane spanning, G protein-linked receptor with a Schiff-base lysine in the seventh membrane span and a Schiff-base counterion in the third membrane span. The primary sequence of P-opsin suggests that it will be maximally sensitive to ∼500-nanometer light and produce a slow and prolonged phototransduction response consistent with the nonvisual function of pineal photoreception.