Illuminating the clock: circadian photobiology.
Light and circadian (daily) clocks are intimately related. Undoubtedly, the daily light/dark cycle has played a key role in the evolution of these oscillators. Now, light and dark signals synchronize these internal timekeepers to the precisely 24 h environmental cycle. Light also affects the period and amplitude of circadian rhythms. The expression of some 'light-responsive' genes are regulated by an intertwining of clock and light control mechanisms. These genes may help us to understand the evolution of circadian rhythmicity and can be employed as tools to identify and clone other genes which encode components of clock mechanisms or of their entrainment pathways.
Johnson
C H
CH
Department of Biology, Vanderbilt University, Nashville, TN 37235.
D002940:Circadian Rhythm / Q000502:physiology*; D017343:Genes, Plant / Q000502:physiology; D008027:Light; D018462:Photobiology; D018521:Plant Physiological Phenomena; D015398:Signal Transduction / Q000502:physiology