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Effect of Light on Expression of Clock Genes in Xenopus laevis Melanophores
Author(s) -
Magalhães Moraes Maria Nathália de Carvalho,
Oliveira Poletini Maristela,
Ribeiro Ramos Bruno Cesar,
Lima Leonardo Henrique Ribeiro Graciani,
Lauro Castrucci Ana Maria
Publication year - 2014
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/php.12230
Subject(s) - per2 , per1 , melanopsin , xenopus , biology , clock , chromatophore , circadian clock , microbiology and biotechnology , circadian rhythm , gene expression , photopigment , genetics , neuroscience , gene , retina
Light–dark cycles are considered important cues to entrain biological clocks. A feedback loop of clock gene transcription and translation is the molecular basis underlying the mechanism of both central and peripheral clocks. Xenopus laevis embryonic melanophores respond to light with melanin granule dispersion, response possibly mediated by the photopigment melanopsin. To test whether light modulates clock gene expression in Xenopus melanophores, we used q PCR to evaluate the relative m RNA levels of Per1 , Per2 , Clock and Bmal1 in cultured melanophores exposed to light–dark (LD) cycle or constant darkness (DD). LD cycles elicited temporal changes in the expression of Per1 , Per2 and Bmal1 . A 10‐min pulse of blue light was able to increases the expression of Per1 and Per2 . Red light had no effect on the expression of these clock genes. These data suggest the participation of a blue‐wavelength sensitive pigment in the light–dark cycle‐mediated oscillation of the endogenous clock. Our results add an important contribution to the emerging field of peripheral clocks, which in nonmammalian vertebrates have been mostly studied in Drosophila and Danio rerio . Within this context, we show that X. laevis melanophores, which have already led to melanopsin discovery, represent an ideal model to understanding circadian rhythms.