title: The circadian clock machinery during early development of Senegalese sole (Solea senegalensis): effects of constant light and dark conditions.
abstract: Circadian rhythms are established very early during vertebrate development. In fish, environmental cues can influence the initiation and synchronization of different rhythmic processes. Previous studies in zebrafish and rainbow trout have shown that circadian oscillation of clock genes represents one of the earliest detectable rhythms in the developing embryo, suggesting their significance in regulating the coordination of developmental processes. In this study, we analyzed the daily expression of the core clock components Per1, Per2, Per3, and Clock during the first several days of Senegalese sole development (0-4 d post fertilization or dpf) under different lighting regimes, with the aim of addressing when the molecular clock first emerges in this species and how it is affected by different photoperiods. Rhythmic expression of the above genes was detected from 0 to 1 dpf, being markedly affected in the next few days by both constant light (LL) and dark (DD) conditions. A gradual entrainment of the clock machinery was observed only under light-dark (LD) cycles, and robust rhythms with increased amplitudes were established by 4 dpf for all clock genes currently studied. Our results show the existence of an embryonic molecular clock from the 1st d of development in Senegalese sole and emphasize the significance of cycling LD conditions when raising embryos and early larvae.
authors.affiliation: Departamento de Biología, Facultad de Ciencias del Mar y Ambientales, Universidad de Cádiz, Campus de Excelencia Internacional del Mar (CEI MAR), Puerto Real, Spain.
authors.forename: Agueda J
authors.initials: AJ
authors.lastname: Martín-Robles
authors.forename: María
authors.initials: M
authors.lastname: Aliaga-Guerrero
authors.forename: David
authors.initials: D
authors.lastname: Whitmore
authors.forename: Carlos
authors.initials: C
authors.lastname: Pendón
authors.forename: José A
authors.initials: JA
authors.lastname: Muñoz-Cueto
mesh_terms: D000818:Animals; D056926:CLOCK Proteins / Q000235:genetics / Q000502:physiology; D057906:Circadian Clocks / Q000235:genetics / Q000502:physiology*; D029941:Fish Proteins / Q000235:genetics / Q000502:physiology; D005412:Flatfishes / Q000196:embryology* / Q000235:genetics / Q000502:physiology*; D018507:Gene Expression Regulation, Developmental; D056950:Period Circadian Proteins / Q000235:genetics / Q000502:physiology; D017440:Photoperiod; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism
chemical_list: D029941:Fish Proteins; D056950:Period Circadian Proteins; D012333:RNA, Messenger; D056926:CLOCK Proteins