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Differential Contribution of Rod and Cone Circadian Clocks in Driving Retinal Melatonin Rhythms in Xenopus
BACKGROUND: Although an endogenous circadian clock located in the retinal photoreceptor layer governs various physiological events including melatonin rhythms in Xenopus laevis, it remains unknown which of the photoreceptors, rod and/or cone, is responsible for the circadian regulation of melatonin...
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Formato: | Texto |
Lenguaje: | English |
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Public Library of Science
2010
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3004937/ https://www.ncbi.nlm.nih.gov/pubmed/21187976 http://dx.doi.org/10.1371/journal.pone.0015599 |
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author | Hayasaka, Naoto LaRue, Silvia I. Green, Carla B. |
author_facet | Hayasaka, Naoto LaRue, Silvia I. Green, Carla B. |
author_sort | Hayasaka, Naoto |
collection | PubMed |
description | BACKGROUND: Although an endogenous circadian clock located in the retinal photoreceptor layer governs various physiological events including melatonin rhythms in Xenopus laevis, it remains unknown which of the photoreceptors, rod and/or cone, is responsible for the circadian regulation of melatonin release. METHODOLOGY/PRINCIPAL FINDINGS: We selectively disrupted circadian clock function in either the rod or cone photoreceptor cells by generating transgenic Xenopus tadpoles expressing a dominant-negative CLOCK (XCLΔQ) under the control of a rod or cone-specific promoter. Eyecup culture and continuous melatonin measurement revealed that circadian rhythms of melatonin release were abolished in a majority of the rod-specific XCLΔQ transgenic tadpoles, although the percentage of arrhythmia was lower than that of transgenic tadpole eyes expressing XCLΔQ in both rods and cones. In contrast, whereas a higher percentage of arrhythmia was observed in the eyes of the cone-specific XCLΔQ transgenic tadpoles compare to wild-type counterparts, the rate was significantly lower than in rod-specific transgenics. The levels of the transgene expression were comparable between these two different types of transgenics. In addition, the average overall melatonin levels were not changed in the arrhythmic eyes, suggesting that CLOCK does not affect absolute levels of melatonin, only its temporal expression pattern. CONCLUSIONS/SIGNIFICANCE: These results suggest that although the Xenopus retina is made up of approximately equal numbers of rods and cones, the circadian clocks in the rod cells play a dominant role in driving circadian melatonin rhythmicity in the Xenopus retina, although some contribution of the clock in cone cells cannot be excluded. |
format | Text |
id | pubmed-3004937 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2010 |
publisher | Public Library of Science |
record_format | MEDLINE/PubMed |
spelling | pubmed-30049372010-12-27 Differential Contribution of Rod and Cone Circadian Clocks in Driving Retinal Melatonin Rhythms in Xenopus Hayasaka, Naoto LaRue, Silvia I. Green, Carla B. PLoS One Research Article BACKGROUND: Although an endogenous circadian clock located in the retinal photoreceptor layer governs various physiological events including melatonin rhythms in Xenopus laevis, it remains unknown which of the photoreceptors, rod and/or cone, is responsible for the circadian regulation of melatonin release. METHODOLOGY/PRINCIPAL FINDINGS: We selectively disrupted circadian clock function in either the rod or cone photoreceptor cells by generating transgenic Xenopus tadpoles expressing a dominant-negative CLOCK (XCLΔQ) under the control of a rod or cone-specific promoter. Eyecup culture and continuous melatonin measurement revealed that circadian rhythms of melatonin release were abolished in a majority of the rod-specific XCLΔQ transgenic tadpoles, although the percentage of arrhythmia was lower than that of transgenic tadpole eyes expressing XCLΔQ in both rods and cones. In contrast, whereas a higher percentage of arrhythmia was observed in the eyes of the cone-specific XCLΔQ transgenic tadpoles compare to wild-type counterparts, the rate was significantly lower than in rod-specific transgenics. The levels of the transgene expression were comparable between these two different types of transgenics. In addition, the average overall melatonin levels were not changed in the arrhythmic eyes, suggesting that CLOCK does not affect absolute levels of melatonin, only its temporal expression pattern. CONCLUSIONS/SIGNIFICANCE: These results suggest that although the Xenopus retina is made up of approximately equal numbers of rods and cones, the circadian clocks in the rod cells play a dominant role in driving circadian melatonin rhythmicity in the Xenopus retina, although some contribution of the clock in cone cells cannot be excluded. Public Library of Science 2010-12-20 /pmc/articles/PMC3004937/ /pubmed/21187976 http://dx.doi.org/10.1371/journal.pone.0015599 Text en Hayasaka et al. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited. |
spellingShingle | Research Article Hayasaka, Naoto LaRue, Silvia I. Green, Carla B. Differential Contribution of Rod and Cone Circadian Clocks in Driving Retinal Melatonin Rhythms in Xenopus |
title | Differential Contribution of Rod and Cone Circadian Clocks in Driving Retinal Melatonin Rhythms in Xenopus
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title_full | Differential Contribution of Rod and Cone Circadian Clocks in Driving Retinal Melatonin Rhythms in Xenopus
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title_fullStr | Differential Contribution of Rod and Cone Circadian Clocks in Driving Retinal Melatonin Rhythms in Xenopus
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title_full_unstemmed | Differential Contribution of Rod and Cone Circadian Clocks in Driving Retinal Melatonin Rhythms in Xenopus
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title_short | Differential Contribution of Rod and Cone Circadian Clocks in Driving Retinal Melatonin Rhythms in Xenopus
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title_sort | differential contribution of rod and cone circadian clocks in driving retinal melatonin rhythms in xenopus |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3004937/ https://www.ncbi.nlm.nih.gov/pubmed/21187976 http://dx.doi.org/10.1371/journal.pone.0015599 |
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