RRC ID 2005
Author Fujiki Y, Ito M, Nishida I, Watanabe A.
Title Multiple signaling pathways in gene expression during sugar starvation. Pharmacological analysis of din gene expression in suspension-cultured cells of Arabidopsis.
Journal Plant Physiol.
Abstract We have identified many dark-inducible (din) genes that are expressed in Arabidopsis leaves kept in the dark. In the present study we addressed the question of how plant cells sense the depletion of sugars, and how sugar starvation triggers din gene expression in suspension-cultured cells of Arabidopsis. Depletion of sucrose in the medium triggered marked accumulation of din transcripts. Suppression of din gene expression by 2-deoxy-Glc, and a non-suppressive effect exerted by 3-O-methyl-Glc, suggested that sugar-repressible expression of din genes is mediated through the phosphorylation of hexose by hexokinase, as exemplified in the repression of photosynthetic genes by sugars. We have further shown that the signaling triggered by sugar starvation involves protein phosphorylation and dephosphorylation events, and have provided the first evidence that multiple pathways of protein dephosphorylation exist in sugar starvation-induced gene expression. An inhibitor of serine/threonine protein kinase, K-252a, inhibited din gene expression in sugar-depleted cells. Okadaic acid, which may preferentially inhibit type 2A protein phosphatases over type 1, enhanced the transcript levels of all din genes, except din6 and din10, under sugar starvation. Conversely, a more potent inhibitor of type 1 and 2A protein phosphatases, calyculin A, increased transcripts from din2 and din9, but decreased those from other din genes, in sugar-depleted cells. On the other hand, calyculin A, but not okadaic acid, completely inhibited the gene expression of chlorophyll a/b-binding protein under sugar starvation. These results indicate that multiple signaling pathways, mediated by different types of protein phosphatases, regulate gene expression during sugar starvation.
Volume 124(3)
Pages 1139-48
Published 2000-11
PMID 11080291
PMC PMC59213
MeSH Arabidopsis / genetics* Arabidopsis / metabolism Blotting, Northern Carbohydrates / deficiency* Cells, Cultured Cycloheximide / pharmacology Cytochrome c Group / genetics Cytochrome c Group / metabolism Darkness* Enzyme Inhibitors / pharmacology Gene Expression Regulation, Plant* Genes, Plant* Light-Harvesting Protein Complexes Okadaic Acid / pharmacology Oxazoles / pharmacology Oxidoreductases / genetics Oxidoreductases / metabolism Phosphoprotein Phosphatases / antagonists & inhibitors Phosphorylation Photosynthetic Reaction Center Complex Proteins / genetics Photosynthetic Reaction Center Complex Proteins / metabolism Plant Proteins / genetics Plant Proteins / metabolism Protein Kinase Inhibitors Protein Synthesis Inhibitors / pharmacology Signal Transduction
IF 6.305
Times Cited 58
Arabidopsis / Cultured plant cells, genes rpc00008