title: Coordinated transcriptional regulation underlying the circadian clock in Arabidopsis.
abstract: The circadian clock controls many metabolic, developmental and physiological processes in a time-of-day-specific manner in both plants and animals. The photoreceptors involved in the perception of light and entrainment of the circadian clock have been well characterized in plants. However, how light signals are transduced from the photoreceptors to the central circadian oscillator, and how the rhythmic expression pattern of a clock gene is generated and maintained by diurnal light signals remain unclear. Here, we show that in Arabidopsis thaliana, FHY3, FAR1 and HY5, three positive regulators of the phytochrome A signalling pathway, directly bind to the promoter of ELF4, a proposed component of the central oscillator, and activate its expression during the day, whereas the circadian-controlled CCA1 and LHY proteins directly suppress ELF4 expression periodically at dawn through physical interactions with these transcription-promoting factors. Our findings provide evidence that a set of light- and circadian-regulated transcription factors act directly and coordinately at the ELF4 promoter to regulate its cyclic expression, and establish a potential molecular link connecting the environmental light-dark cycle to the central oscillator.
authors.affiliation: Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, Connecticut 06520, USA.
authors.forename: Gang
authors.initials: G
authors.lastname: Li
authors.forename: Hamad
authors.initials: H
authors.lastname: Siddiqui
authors.forename: Yibo
authors.initials: Y
authors.lastname: Teng
authors.forename: Rongcheng
authors.initials: R
authors.lastname: Lin
authors.forename: Xiang-yuan
authors.initials: XY
authors.lastname: Wan
authors.forename: Jigang
authors.initials: J
authors.lastname: Li
authors.forename: On-Sun
authors.initials: OS
authors.lastname: Lau
authors.forename: Xinhao
authors.initials: X
authors.lastname: Ouyang
authors.forename: Mingqiu
authors.initials: M
authors.lastname: Dai
authors.forename: Jianmin
authors.initials: J
authors.lastname: Wan
authors.forename: Paul F
authors.initials: PF
authors.lastname: Devlin
authors.forename: Xing Wang
authors.initials: XW
authors.lastname: Deng
authors.forename: Haiyang
authors.initials: H
authors.lastname: Wang
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000502:physiology; D002940:Circadian Rhythm; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D030821:Plants, Genetically Modified; D015398:Signal Transduction; D014158:Transcription, Genetic