title: Light-induced nuclear import of phytochrome-A:GFP fusion proteins is differentially regulated in transgenic tobacco and Arabidopsis.
abstract: Phytochromes (phy) are a family of photoreceptors that control various aspects of light-dependent plant development. Phytochrome A (phyA) is responsible for the very low fluence response (VLFR) under inductive light conditions and for the high irradiance response (HIR) under continuous far-red light. We have recently shown that nuclear import of rice phyA:GFP is regulated by VLFR in transgenic tobacco. The import is preceded by very fast, light-induced formation of sequestered areas of phyA:GFP in the cytosol. Here we report that expression of the Arabidopsis phyA:GFP fusion protein in phyA-deficient Arabidopsis plants complements the mutant phenotype. In these transgenic Arabidopsis lines, both light-dependent cytosolic formation of sequestered areas of the phyA:GFP as well as VLFR or HIR-mediated nuclear import of the fusion protein was observed. By contrast, light-dependent nuclear import of the same fusion protein was induced only by continuous far-red light (HIR) but not by pulses of far-red light (VLFR) in transgenic tobacco. These results demonstrate that photoregulation of intracellular partitioning of the Arabidopsis phyA:GFP differs significantly in different genetic backgrounds.
authors.affiliation: Universitat Freiburg, Institut für Biologie II/Botanik, Schänzlestrasse 1, D-79104 Freiburg, Germany.
authors.forename: L
authors.initials: L
authors.lastname: Kim
authors.forename: S
authors.initials: S
authors.lastname: Kircher
authors.forename: R
authors.initials: R
authors.lastname: Toth
authors.forename: E
authors.initials: E
authors.lastname: Adam
authors.forename: E
authors.initials: E
authors.lastname: Schäfer
authors.forename: F
authors.initials: F
authors.lastname: Nagy
mesh_terms: D017360:Arabidopsis / Q000378:metabolism / Q000502:physiology*; D029681:Arabidopsis Proteins; D002451:Cell Compartmentation / Q000502:physiology; D002467:Cell Nucleus / Q000378:metabolism* / Q000502:physiology; D049452:Green Fluorescent Proteins; D008027:Light; D008164:Luminescent Proteins / Q000235:genetics; D008856:Microscopy, Fluorescence; D010834:Phytochrome / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D051942:Phytochrome A; D030821:Plants, Genetically Modified; D010947:Plants, Toxic; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D014026:Nicotiana / Q000378:metabolism / Q000502:physiology*
chemical_list: D029681:Arabidopsis Proteins; D008164:Luminescent Proteins; C497973:PHYA protein, Arabidopsis; D051942:Phytochrome A; D011993:Recombinant Fusion Proteins; D010834:Phytochrome; D049452:Green Fluorescent Proteins