title: Influence of moonlight on mRNA expression patterns of melatonin receptor subtypes in the pineal organ of a tropical fish.
abstract: The goldlined spinefoot, Siganus guttatus, is a lunar-synchronized spawner, which repeatedly releases gametes around the first quarter moon during the reproductive season. A previous study reported that manipulating moonlight brightness at night disrupted synchronized spawning, suggesting involvement of this natural light source in lunar synchronization. The present study examined whether the mRNA expression pattern of melatonin receptor subtypes MT1 and Mel1c in the pineal organ of the goldlined spinefoot is related to moonlight. Real-time quantitative polymerase chain reaction analysis revealed that the abundance of MT1 and Mel1c mRNA at midnight increased during the new moon phase and decreased during the full moon phase. Exposing fish to moonlight intensity during the full moon period resulted in a decrease in Mel1c mRNA abundance within 1h. Fluctuations in the melatonin receptor genes according to changes in the moon phase agreed with those of melatonin levels in the blood. These results indicate that periodic changes in cues from the moon influence melatonin receptor mRNA expression levels. The melatonin-melatonin receptor system may play a role in predicting the moon phase through changes in night brightness.
authors.affiliation: Department of Chemistry, Biology and Marine Science, University of the Ryukyus, 1 Senbaru, Nishihara, Okinawa 903-0213, Japan; Marine and Environmental Research Institute, Jeju National University, 3288 Hamdeok, Jocheon, Jeju-do 695-814, Republic of Korea.
authors.forename: Yong-Ju
authors.initials: YJ
authors.lastname: Park
authors.affiliation: Department of Life Science, Jeju National University, 66 Jejudaehakno, Jeju-do 690-756, Republic of Korea.
authors.forename: Ji-Gweon
authors.initials: JG
authors.lastname: Park
authors.affiliation: Department of Chemistry, Biology and Marine Science, University of the Ryukyus, 1 Senbaru, Nishihara, Okinawa 903-0213, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Takeuchi
authors.affiliation: Department of Chemistry, Biology and Marine Science, University of the Ryukyus, 1 Senbaru, Nishihara, Okinawa 903-0213, Japan; Marine and Environmental Research Institute, Jeju National University, 3288 Hamdeok, Jocheon, Jeju-do 695-814, Republic of Korea.
authors.forename: Sung-Pyo
authors.initials: SP
authors.lastname: Hur
authors.affiliation: Marine and Environmental Research Institute, Jeju National University, 3288 Hamdeok, Jocheon, Jeju-do 695-814, Republic of Korea.
authors.forename: Young-Don
authors.initials: YD
authors.lastname: Lee
authors.affiliation: Department of Life Science, Jeju National University, 66 Jejudaehakno, Jeju-do 690-756, Republic of Korea.
authors.forename: Se-Jae
authors.initials: SJ
authors.lastname: Kim
authors.affiliation: Department of Chemistry, Biology and Marine Science, University of the Ryukyus, 1 Senbaru, Nishihara, Okinawa 903-0213, Japan. Electronic address: takemura@sci.u-ryukyu.ac.jp.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Takemura
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D017931:DNA Primers / Q000235:genetics; D015200:Fluoroimmunoassay; D005786:Gene Expression Regulation / Q000502:physiology* / Q000528:radiation effects; D007564:Japan; D008550:Melatonin / Q000097:blood; D016081:Moon; D010473:Perciformes / Q000502:physiology*; D010507:Periodicity; D010870:Pineal Gland / Q000378:metabolism; D021122:Protein Subunits / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D044094:Receptors, Melatonin / Q000378:metabolism*; D012098:Reproduction / Q000502:physiology*
chemical_list: D017931:DNA Primers; D021122:Protein Subunits; D044094:Receptors, Melatonin; D008550:Melatonin
keywords: Goldlined spinefoot; Lunar cycle; Melatonin; Moonlight; Rabbitfish; Real-time quantitative polymerase chain reaction