title: The Arabidopsis SRR1 gene mediates phyB signaling and is required for normal circadian clock function.
abstract: Plants possess several photoreceptors to sense the light environment. In Arabidopsis cryptochromes and phytochromes play roles in photomorphogenesis and in the light input pathways that synchronize the circadian clock with the external world. We have identified SRR1 (sensitivity to red light reduced), a gene that plays an important role in phytochrome B (phyB)-mediated light signaling. The recessive srr1 null allele and phyB mutants display a number of similar phenotypes indicating that SRR1 is required for normal phyB signaling. Genetic analysis suggests that SRR1 works both in the phyB pathway but also independently of phyB. srr1 mutants are affected in multiple outputs of the circadian clock in continuous light conditions, including leaf movement and expression of the clock components, CCA1 and TOC1. Clock-regulated gene expression is also impaired during day-night cycles and in constant darkness. The circadian phenotypes of srr1 mutants in all three conditions suggest that SRR1 activity is required for normal oscillator function. The SRR1 gene was identified and shown to code for a protein conserved in numerous eukaryotes including mammals and flies, implicating a conserved role for this protein in both the animal and plant kingdoms.
authors.affiliation: Institute for Plant Sciences, Swiss Federal Institute of Technology, ETH Center, Zurich, Switzerland.
authors.forename: Dorothee
authors.initials: D
authors.lastname: Staiger
authors.forename: Laure
authors.initials: L
authors.lastname: Allenbach
authors.forename: Neeraj
authors.initials: N
authors.lastname: Salathia
authors.forename: Vincent
authors.initials: V
authors.lastname: Fiechter
authors.forename: Seth J
authors.initials: SJ
authors.lastname: Davis
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Millar
authors.forename: Joanne
authors.initials: J
authors.lastname: Chory
authors.forename: Christian
authors.initials: C
authors.lastname: Fankhauser
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics* / Q000502:physiology* / Q000528:radiation effects; D029681:Arabidopsis Proteins / Q000235:genetics / Q000502:physiology*; D002940:Circadian Rhythm / Q000235:genetics* / Q000502:physiology*; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D008969:Molecular Sequence Data; D009154:Mutation; D010786:Photoreceptor Cells; D010802:Phylogeny; D010834:Phytochrome / Q000235:genetics / Q000502:physiology*; D051939:Phytochrome B; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D014157:Transcription Factors / Q000235:genetics / Q000502:physiology
chemical_list: D029681:Arabidopsis Proteins; C114425:CCA1 protein, Arabidopsis; C497952:PHYB protein, Arabidopsis; C511730:SRR1 protein, Arabidopsis; C411822:TOC1 protein, Arabidopsis; D014157:Transcription Factors; D010834:Phytochrome; D051939:Phytochrome B