title: Functional interaction of phytochrome B and cryptochrome 2.
abstract: Light is a crucial environmental signal that controls many photomorphogenic and circadian responses in plants. Perception and transduction of light is achieved by at least two principal groups of photoreceptors, phytochromes and cryptochromes. Phytochromes are red/far-red light-absorbing receptors encoded by a gene family of five members (phyA to phyE) in Arabidopsis. Cryptochrome 1 (cry1), cryptochrome 2 (cry2) and phototropin are the blue/ultraviolet-A light receptors that have been characterized in Arabidopsis. Previous studies showed that modulation of many physiological responses in plants is achieved by genetic interactions between different photoreceptors; however, little is known about the nature of these interactions and their roles in the signal transduction pathway. Here we show the genetic interaction that occurs between the Arabidopsis photoreceptors phyB and cry2 in the control of flowering time, hypocotyl elongation and circadian period by the clock. PhyB interacts directly with cry2 as observed in co-immunoprecipitation experiments with transgenic Arabidopsis plants overexpressing cry2. Using fluorescent resonance energy transfer microscopy, we show that phyB and cry2 interact in nuclear speckles that are formed in a light-dependent fashion.
authors.affiliation: Department of Cell Biology and National Science Foundation Center for Biological Timing, The Scripps Research Institute, La Jolla, California 92037, USA.
authors.forename: P
authors.initials: P
authors.lastname: Más
authors.forename: P F
authors.initials: PF
authors.lastname: Devlin
authors.forename: S
authors.initials: S
authors.lastname: Panda
authors.forename: S A
authors.initials: SA
authors.lastname: Kay
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development / Q000502:physiology; D029681:Arabidopsis Proteins; D002467:Cell Nucleus / Q000378:metabolism; D002940:Circadian Rhythm / Q000235:genetics; D056931:Cryptochromes; D029721:Drosophila Proteins; D005136:Eye Proteins; D005420:Flavoproteins / Q000235:genetics / Q000502:physiology*; D008027:Light; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D010786:Photoreceptor Cells; D017956:Photoreceptor Cells, Invertebrate; D010834:Phytochrome / Q000235:genetics / Q000502:physiology*; D051939:Phytochrome B; D030821:Plants, Genetically Modified; D011233:Precipitin Tests; D011485:Protein Binding; D043562:Receptors, G-Protein-Coupled; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors; D014162:Transfection
chemical_list: D029681:Arabidopsis Proteins; C538962:CRY1 protein, Arabidopsis; D056931:Cryptochromes; D029721:Drosophila Proteins; D005136:Eye Proteins; D005420:Flavoproteins; C497952:PHYB protein, Arabidopsis; D043562:Receptors, G-Protein-Coupled; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; C119828:cry protein, Drosophila; D010834:Phytochrome; D051939:Phytochrome B