Related Experiment Video
Updated: Aug 6, 2026
07:59
Tracking Cells in GFP-transgenic Zebrafish Using the Photoconvertible PSmOrange System
Published on: February 5, 2016
Pinopsin is a chicken pineal photoreceptive molecule
T Okano1, T Yoshizawa, Y Fukada
1Department of Pure and Applied Sciences, College of Arts and Sciences, University of Tokyo, Japan.
Nature
|November 3, 1994
Summary
Researchers identified a novel light-sensing molecule, pinopsin, in chicken pinealocytes. This discovery sheds light on the molecular mechanisms of the avian biological clock and melatonin production.
Area of Science:
- * Molecular Biology
- * Chronobiology
- * Vision Science
Background:
- * Avian pinealocytes regulate circadian rhythms and melatonin production via light signals.
- * The pineal phototransduction pathway is crucial for understanding the biological clock.
- * Similarities exist between retinal rod cells and pinealocytes in phototransduction.
Purpose of the Study:
- * To identify the photoreceptive molecule in avian pinealocytes.
- * To elucidate the molecular mechanism of the avian biological clock.
- * To characterize the cloned pineal photoreceptor.
Main Methods:
- * Cloning of chicken pineal cDNA encoding a photoreceptive molecule.
- * Transfection of complementary DNA into cultured cells.
- * Reconstitution of the expressed protein with 11-cis-retinal.
Main Results:
- * A novel opsin, named pinopsin, was cloned from chicken pineal cDNA.
- * Chicken pineal opsin shares 43-48% amino acid identity with vertebrate retinal opsins.
- * Expressed pinopsin reconstituted with 11-cis-retinal formed a blue-sensitive pigment (λmax ≈ 470 nm).
- * The gene encoding pinopsin is specifically expressed in the pineal gland.
Conclusions:
- * Pinopsin functions as the primary photosensor in the avian pineal gland.
- * This finding reveals a key molecular component of the avian circadian clock.
- * The study provides functional evidence for pinopsin's role in phototransduction.
Related Concept Videos
01:32The Retina
The retina is a layer of nervous tissue at the back of the eye that transduces light into neural signals. This process, called phototransduction, is carried out by rod and cone photoreceptor cells in the back of the retina.
02:00Photoreceptors and Plant Responses to Light
Light plays a significant role in regulating the growth and development of plants. In addition to providing energy for photosynthesis, light provides other important cues to regulate a range of developmental and physiological responses in plants.
02:45Biological Clocks and Seasonal Responses
The circadian—or biological—clock is an intrinsic, timekeeping, molecular mechanism that allows plants to coordinate physiological activities over 24-hour cycles called circadian rhythms. Photoperiodism is a collective term for the biological responses of plants to variations in the relative lengths of dark and light periods. The period of light-exposure is called the photoperiod.
01:11Channel Rhodopsins
Most organisms use photoreceptors to sense and respond to light. Examples of photoreceptors include bacteriorhodopsins and bacteriophytochromes in some bacteria, phytochromes in plants, and rhodopsins in the photoreceptor cells of the vertebral retina. The light-sensitive property of these receptors is because of the bound chromophores, such as bilin in the phytochromes and retinal in the rhodopsins.
Rhodopsins belong to the family of cell surface proteins called G-protein coupled receptors,...
Rhodopsins belong to the family of cell surface proteins called G-protein coupled receptors,...
01:20Anatomy of the Eyeball
The eye is a spherical, hollow structure composed of three tissue layers. The outer layer — the fibrous tunic, comprises the sclera — a white structure — and the cornea, which is transparent. The sclera encompasses some of the ocular surface, most of which is not visible. However, the 'white of the eye' is distinctively visible in humans compared to other species. The cornea, a clear covering at the front of the eye, enables light penetration. The eye's middle layer, the vascular tunic,...
01:22Photoreceptors and Visual Pathways
At the molecular level, visual signals trigger transformations in photopigment molecules, resulting in changes in the photoreceptor cell's membrane potential. The photon's energy level is denoted by its wavelength, with each specific wavelength of visible light associated with a distinct color. The spectral range of visible light, classified as electromagnetic radiation, spans from 380 to 720 nm. Electromagnetic radiation wavelengths exceeding 720 nm fall under the infrared category, whereas...