Light inactivation of Arabidopsis photomorphogenic repressor COP1 involves a cell-specific regulation of its nucleocytoplasmic partitioning.
Arabidopsis COP1 acts as a repressor of photomorphogenesis in darkness, and light stimuli abrogate this suppressive action. COP1, when fused to beta-glucuronidase (GUS), is enriched in the nucleus in darkness, but not in the light, in hypocotyl cells of Arabidopsis seedlings and epidermal cells of onion bulbs. In Arabidopsis hypocotyl cells, the nuclear GUS-COP1 level changes in response to dark-light transitions and quantitatively correlates with the extent of repression of photomorphogenic development. In root cells, GUS-COP1 is constitutively nuclear, consistent with an established role of COP1 in suppressing root chloroplast development in both light and darkness. We conclude that COP1 acts inside the nucleus to suppress photomorphogenesis and that light inactivation of COP1 involves a cell type-specific control of its nucleocytoplasmic partitioning.
von Arnim
A G
AG
Department of Biology, Yale University, New Haven, Connecticut 06520-8104.
Deng
X W
XW
D000490:Allium / Q000528:radiation effects; D017360:Arabidopsis / Q000254:growth & development / Q000528:radiation effects*; D029681:Arabidopsis Proteins; D002352:Carrier Proteins / Q000378:metabolism*; D002451:Cell Compartmentation; D002467:Cell Nucleus / Q000378:metabolism; D002736:Chloroplasts / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D003624:Darkness; D015870:Gene Expression; D005966:Glucuronidase / Q000235:genetics / Q000378:metabolism; D018546:Hypocotyl / Q000378:metabolism / Q000528:radiation effects; D008027:Light; D008954:Models, Biological; D009024:Morphogenesis / Q000528:radiation effects; D010940:Plant Proteins / Q000378:metabolism*; D018517:Plant Roots / Q000378:metabolism; D030821:Plants, Genetically Modified; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012097:Repressor Proteins / Q000378:metabolism*; D012639:Seeds / Q000254:growth & development / Q000378:metabolism; D015398:Signal Transduction; D014018:Tissue Distribution; D044767:Ubiquitin-Protein Ligases
D029681:Arabidopsis Proteins; D002352:Carrier Proteins; D010940:Plant Proteins; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; C471983:AT2G32950 protein, Arabidopsis; D044767:Ubiquitin-Protein Ligases; D005966:Glucuronidase