Gibberellins signal nuclear import of PHOR1, a photoperiod-responsive protein with homology to Drosophila armadillo.
S. tuberosum ssp. andigena potato plants require short days (SD) for tuberization. We have isolated PHOR1 (photoperiod-responsive 1), which shows upregulated expression in induced leaves (SD). PHOR1 encodes an arm repeat protein with homology to the Drosophila segment polarity protein armadillo. Antisense inhibition of PHOR1 produces a semidwarf phenotype similar to that of GA-deficient plants, and the antisense lines show reduced GA responsiveness combined with a higher endogenous GA content than wild-type plants. Feedback regulation of GA biosynthetic genes is also altered in these lines. Conversely, transgenic lines overexpressing PHOR1 show an enhanced response to GA. GA application induces rapid migration of PHOR1-GFP protein to the nucleus. Thus, PHOR1 appears to be a general component of GA signaling pathways that relocalizes to the nucleus in the presence of GA.
Amador
V
V
Departament de Genètica Molecular, Institut de Biologia Molecular de Barcelona-CSIC, Jordi Girona, 18-26, 08034 Barcelona, Spain.
Monte
E
E
García-Martínez
J L
JL
Prat
S
S
D021581:Active Transport, Cell Nucleus / Q000187:drug effects; D000595:Amino Acid Sequence; D051186:Armadillo Domain Proteins; D002460:Cell Line; D002940:Circadian Rhythm; D003001:Cloning, Molecular; D017124:Conserved Sequence; D004305:Dose-Response Relationship, Drug; D029721:Drosophila Proteins; D005246:Feedback / Q000187:drug effects; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D005875:Gibberellins / Q000096:biosynthesis / Q000378:metabolism / Q000494:pharmacology*; D019476:Insect Proteins / Q000737:chemistry*; D008027:Light; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D010641:Phenotype; D017440:Photoperiod; D010940:Plant Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D018517:Plant Roots / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D030821:Plants, Genetically Modified; D016372:RNA, Antisense / Q000235:genetics; D018749:RNA, Plant / Q000235:genetics / Q000378:metabolism; D020449:Repetitive Sequences, Amino Acid / Q000235:genetics; D015398:Signal Transduction / Q000187:drug effects*; D011198:Solanum tuberosum / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D015534:Trans-Activators; D015854:Up-Regulation / Q000187:drug effects
D051186:Armadillo Domain Proteins; D029721:Drosophila Proteins; D005875:Gibberellins; D019476:Insect Proteins; C433723:PHOR1 protein, Solanum tuberosum; D010940:Plant Proteins; D016372:RNA, Antisense; D018749:RNA, Plant; D015534:Trans-Activators