Amphibian melanophores become photosensitive when treated with retinal

Rollag, Mark D.

doi:10.1002/(sici)1097-010x(19960501)275:1<20::aid-jez4>3.0.co;2-c

Cited by 28 publications

(28 citation statements)

References 28 publications

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“…Melanopsin, a molecule found originally in frog skin lightsensitive melanophore cells was an early leading candidate for the mammalian circadian photopigment, since it is expressed in anatomical areas where a nonvisual photoreceptor is likely to be present (Rollag, 1996;Provencio et al, 1998). Melanopsin also shares predicted structural similarities with all known opsins, including seven transmembrane proteins.…”

Section: The Discovery Of Melanopsin and Intrinsically Photosensitivementioning

confidence: 99%

Photoreception for Circadian, Neuroendocrine, and Neurobehavioral Regulation

Hanifin

Brainard

2007

J Physiol Anthropol

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In the art and science of lighting, four traditional objectives have been to provide light that: 1) is optimum for visual performance; 2) is visually comfortable; 3) permits aesthetic appreciation of the space; and 4) conserves energy. Over the past 25 years, it has been demonstrated that there are nonvisual, systemic effects of light in healthy humans. Furthermore, light has been used to successfully treat patients with selected affective and sleep disorders as well as healthy individuals who have circadian disruption due to shift work, transcontinental jet travel, or space flight. Recently, there has been an upheaval in the understanding of photoreceptive input to the circadian system of humans and other mammals. Analytical action spectra in rodents, primates, and humans have identified 446-484 nm (predominantly the blue part of the spectrum) as the most potent wavelength region for neuroendocrine, circadian, and neurobehavioral responses. Those studies suggested that a novel photosensory system, distinct from the visual rods and cones, is primarily responsible for this regulation. Studies have now shown that this new photosensory system is based on a small population of widely dispersed retinal ganglion cells that are intrinsically responsive to light, and project to the suprachiasmatic nuclei and other nonvisual centers in the brain. These light-sensitive retinal ganglion cells contain melanopsin, a vitamin A photopigment that mediates the cellular phototransduction cascade. Although light detection for circadian and neuroendocrine phototransduction seems to be mediated principally by a novel photosensory system in the eye, the classic rod and cone photoreceptors appear to play a role as well. These findings are important in understanding how humans adapt to lighting conditions in modern society and will provide the basis for major changes in future architectural lighting strategies.

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Section: The Discovery Of Melanopsin and Intrinsically Photosensitivementioning

confidence: 99%

Photoreception for Circadian, Neuroendocrine, and Neurobehavioral Regulation

Hanifin

Brainard

2007

J Physiol Anthropol

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“…Unlike tail melanophores of later-stage tadpoles, melanophores derived from embryos of anuran species, including Xenopus lae6is, disperse their pigment under illumination and aggregate it in darkness (21,22,29,30), whereas melanophores from embryos of urodeles, Ambystoma mexicanum (axolotl) and Pleurodeles waltlii, do not exhibit a similar response (29 2 ), maximum dispersion of the pigment granules occurs after 15-20 min of illumination, with a peak at 460 nm. The photosensitivity of cultured melanophores derived from Xenopus embryos is activated by treatment with all-trans retinal, but the cells fail to disperse their pigment granules under illumination when maintained in retinoid-free medium, suggesting the possible involvement of an opsin in melanophore photosensitivity (30).…”

Section: Light Sensitivity Of Amphibian and Reptilian Chromatophoresmentioning

confidence: 99%

“…The photosensitivity of cultured melanophores derived from Xenopus embryos is activated by treatment with all-trans retinal, but the cells fail to disperse their pigment granules under illumination when maintained in retinoid-free medium, suggesting the possible involvement of an opsin in melanophore photosensitivity (30).…”

Section: Light Sensitivity Of Amphibian and Reptilian Chromatophoresmentioning

confidence: 99%

Direct Reception of Light by Chromatophores of Lower Vertebrates

Oshima

2001

Pigment Cell Research

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Rapid color changes of lower vertebrates are caused by the motile activities of pigment cells (chromatophores) present in the skin tissue. Chromatophore motility is generally regulated by neural and/or by endocrine systems. However, in some cases, light also induces pigment aggregation or dispersion directly, which suggests the existence of visual pigments in chromatophores. In fact, some opsins, including melanopsin, have been identified. This article reviews light‐sensitive chromatophores of lower vertebrates. Photoreceptive molecules (visual pigments) and signal transduction of light via a GTP‐binding protein (G protein) are also discussed.

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“…The melanophore response to these agents has led to the development of innovative systems for studying functional interactions between ligands and their receptors (4,5). Melanophore photosensitivity is reversibly activated by retinaldehydes (6) and has an action spectrum characteristic of opsinlike photopigments (2). In an effort to identify an opsin that may regulate melanosome migration, we have analyzed protein extracts of cultured melanophores for opsin immunoreactivity and screened a melanophore cDNA library for opsin-like nucleotide sequences.…”

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confidence: 99%

Melanopsin: An opsin in melanophores, brain, and eye

Provencio

Jiang

Grip

et al. 1998

Proc. Natl. Acad. Sci. U.S.A.

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We have identified an opsin, melanopsin, in photosensitive dermal melanophores of Xenopus laevis. Its deduced amino acid sequence shares greatest homology with cephalopod opsins. The predicted secondary structure of melanopsin indicates the presence of a long cytoplasmic tail with multiple putative phosphorylation sites, suggesting that this opsin's function may be finely regulated. Melanopsin mRNA is expressed in hypothalamic sites thought to contain deep brain photoreceptors and in the iris, a structure known to be directly photosensitive in amphibians. Melanopsin message is also localized in retinal cells residing in the outermost lamina of the inner nuclear layer where horizontal cells are typically found. Its expression in retinal and nonretinal tissues suggests a role in vision and nonvisual photoreceptive tasks, such as photic control of skin pigmentation, pupillary aperture, and circadian and photoperiodic physiology.Photopigments consist of an integral membrane apoprotein, opsin, that is covalently linked to a retinaldehyde chromophore. Upon illumination, the chromophore is photoisomerized, forcing a conformational change in the surrounding opsin and subsequently initiating an intracellular signaling cascade. The conversion of light into neural signals within photoreceptor cells of the retina is the best studied example of opsin-mediated signaling.Dermal melanophores of Xenopus laevis, like retinal photoreceptors, are photosensitive (1). When maintained in vitro, the melanosomes in dermal melanophores migrate to the cellular periphery in response to illumination (2) or the activation of a wide variety of G protein-coupled receptors (3). The melanophore response to these agents has led to the development of innovative systems for studying functional interactions between ligands and their receptors (4, 5). Melanophore photosensitivity is reversibly activated by retinaldehydes (6) and has an action spectrum characteristic of opsinlike photopigments (2). In an effort to identify an opsin that may regulate melanosome migration, we have analyzed protein extracts of cultured melanophores for opsin immunoreactivity and screened a melanophore cDNA library for opsin-like nucleotide sequences. MATERIALS AND METHODSWestern Blot. Approximately 10 5 cultured Xenopus laevis dermal melanophores were washed twice with 1ϫ calcium-and magnesium-free Dulbecco's phosphate buffer and lysed with lysis buffer [1% IGEPAL CA-630 (Sigma)͞0.2 M NaBH 3 CN͞1 mM phenylmethylsulfonyl fluoride͞aprotinin (0.1 trypsin inhibitor unit͞ml)͞5 mM EDTA͞0.086 M NaC 2 H 3 O 2 , pH 5.0, 4°C]. A homogenate of one early postmetamorphic adult eye was also extracted as above. Lysates were centrifuged and the supernatants subjected to SDS͞PAGE analysis and subsequent electroblotting onto a poly(vinylidene difluoride) membrane. The blot was probed with a 1:2,000 dilution of antisera (CERN 886) raised against bovine rhodopsin and detected by enhanced chemiluminescence.cDNA Library Screen. A X. laevis dermal melanophore oligo(dT) cDNA library was...

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Amphibian melanophores become photosensitive when treated with retinal

Cited by 28 publications

References 28 publications

Photoreception for Circadian, Neuroendocrine, and Neurobehavioral Regulation

Photoreception for Circadian, Neuroendocrine, and Neurobehavioral Regulation

Direct Reception of Light by Chromatophores of Lower Vertebrates

Melanopsin: An opsin in melanophores, brain, and eye

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