title: Using circadian entrainment to find cryptic clocks.
abstract: Three properties are most often attributed to the circadian clock: a ca. 24-h free-running rhythm, temperature compensation of the circadian rhythm, and its entrainment to zeitgeber cycles. Relatively few experiments, however, are performed under entrainment conditions. Rather, most chronobiology protocols concern constant conditions. We have turned this paradigm around and used entrainment to study the circadian clock in organisms where a free-running rhythm is weak or lacking. We describe two examples therein: Caenorhabditis elegans and Saccharomyces cerevisiae. By probing the system with zeitgeber cycles that have various structures and amplitudes, we can demonstrate the establishment of systematic entrained phase angles in these organisms. We conclude that entrainment can be utilized to discover hitherto unknown circadian clocks and we discuss the implications of using entrainment more broadly, even in model systems that show robust free-running rhythms.
authors: Department of Molecular Chronobiology, Groningen, The Netherlands.
authors: Zheng
authors: Z
authors: Eelderink-Chen
authors: Institute of Medical Psychology, Munich, Germany.
authors: Maria
authors: M
authors: Olmedo
authors: Department of Molecular Chronobiology, Groningen, The Netherlands.
authors: Jasper
authors: J
authors: Bosman
authors: Department of Molecular Chronobiology, Groningen, The Netherlands; Institute of Medical Psychology, Munich, Germany. Electronic address: merrow@lmu.de.
authors: Martha
authors: M
authors: Merrow
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans / Q000502:physiology*; D057906:Circadian Clocks; D006801:Humans; D012107:Research Design; D012441:Saccharomyces cerevisiae / Q000502:physiology*
keywords: Circadian; Entrainment; Masking; T cycle; Zeitgeber