title: Hypothalamic expression and moonlight-independent changes of Cry3 and Per4 implicate their roles in lunar clock oscillators of the lunar-responsive Goldlined spinefoot.
abstract: Lunar cycle-associated physiology has been found in a wide variety of organisms. Studies suggest the presence of a circalunar clock in some animals, but the location of the lunar clock is unclear. We previously found lunar-associated expression of transcripts for Cryptochrome3 gene (SgCry3) in the brain of a lunar phase-responsive fish, the Goldlined spinefoot (Siganus guttatus). Then we proposed a photoperiodic model for the lunar phase response, in which SgCry3 might function as a phase-specific light response gene and/or an oscillatory factor in unidentified circalunar clock. In this study, we have developed an anti-SgCRY3 antibody to identify SgCRY3-immunoreactive cells in the brain. We found immunoreactions in the subependymal cells located in the mediobasal region of the diencephalon, a crucial site for photoperiodic seasonal responses in birds. For further assessment of the lunar-responding mechanism and the circalunar clock, we investigated mRNA levels of Cry3 as well as those of the other clock(-related) genes, Period (Per2 and Per4), in S. guttatus reared under nocturnal moonlight interruption or natural conditions. Not only SgCry3 but SgPer4 mRNA levels showed lunar phase-dependent variations in the diencephalon without depending on light condition during the night. These results suggest that the expressions of SgCry3 and SgPer4 are not directly regulated by moonlight stimulation but endogenously mediated in the brain, and implicate that circadian clock(-related) genes may be involved in the circalunar clock locating within the mediobasal region of the diencephalon.
authors.affiliation: Department of Electrical Engineering and Bioscience, Graduate School of Advanced Science and Engineering, Waseda University, TWIns, Tokyo, Japan.
authors.forename: Riko
authors.initials: R
authors.lastname: Toda
authors.affiliation: Department of Electrical Engineering and Bioscience, Graduate School of Advanced Science and Engineering, Waseda University, TWIns, Tokyo, Japan.
authors.forename: Keiko
authors.initials: K
authors.lastname: Okano
authors.affiliation: Department of Chemistry, Biology, and Marine Science, Faculty of Science, University of the Ryukyus, Okinawa, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Takeuchi
authors.affiliation: Department of Chemistry, Biology, and Marine Science, Faculty of Science, University of the Ryukyus, Okinawa, Japan.
authors.forename: Chihiro
authors.initials: C
authors.lastname: Yamauchi
authors.affiliation: Department of Electrical Engineering and Bioscience, Graduate School of Advanced Science and Engineering, Waseda University, TWIns, Tokyo, Japan.
authors.forename: Masato
authors.initials: M
authors.lastname: Fukushiro
authors.affiliation: Department of Chemistry, Biology, and Marine Science, Faculty of Science, University of the Ryukyus, Okinawa, Japan.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Takemura
authors.affiliation: Department of Electrical Engineering and Bioscience, Graduate School of Advanced Science and Engineering, Waseda University, TWIns, Tokyo, Japan.
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Okano
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D005399:Fishes / Q000378:metabolism*; D007031:Hypothalamus / Q000378:metabolism*; D008969:Molecular Sequence Data; D016081:Moon; D011506:Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics; D017386:Sequence Homology, Amino Acid
chemical_list: D011506:Proteins; D012333:RNA, Messenger