title: Post-Translational Regulation of the Dicing Activities of Arabidopsis DICER-LIKE 3 and 4 by Inorganic Phosphate and the Redox State.
abstract: In Arabidopsis thaliana, small interfering RNAs (siRNAs) generated by two Dicer isoforms, DCL3 and DCL4, function in distinct epigenetic processes, i.e. RNA-directed DNA methylation and post-transcriptional gene silencing, respectively. Plants often respond to their environment by producing a distinct set of small RNAs; however, the mechanism for controlling the production of different siRNAs from the same dsRNA substrate remains unclear. We established a simple biochemical method to visualize the dsRNA-cleaving activities of DCL3 and DCL4 in cell-free extracts prepared from Arabidopsis seedlings. Here, we demonstrate that different nutrient statuses of a host plant affect the post-translational regulation of the dicing activity of DCL3 and DCL4. Phosphate deficiency inhibited DCL3, and the activity of DCL3 was directly activated by inorganic phosphate. Sulfur deficiency inhibited DCL4 but not DCL3, and the activity of DCL4 was recovered by supplementation of the cell-free extracts with reductants containing a thiol group. Immunopurified DCL4 was activated by recombinant Arabidopsis thioredoxin-h1 with dithiothreitol. Therefore, DCL4 is subject to redox regulation. These results demonstrate that post-translational regulation of DCL activities fine-tunes the balance between branches of the gene silencing pathway according to the growth environment.
authors.affiliation: Department of Applied Biological Sciences, Tokyo University of Agriculture and Technology, Saiwaicho, Fuchu, Tokyo, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Seta
authors.affiliation: Department of Applied Biological Sciences, Tokyo University of Agriculture and Technology, Saiwaicho, Fuchu, Tokyo, Japan.
authors.forename: Midori
authors.initials: M
authors.lastname: Tabara
authors.affiliation: Department of Applied Biological Sciences, Tokyo University of Agriculture and Technology, Saiwaicho, Fuchu, Tokyo, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Nishibori
authors.affiliation: Department of Clinical Plant Science, Hosei University, Kajino-cho, Koganei, Tokyo, Japan.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Hiraguri
authors.affiliation: Biological Production Science, Tokyo University of Agriculture and Technology, Saiwaicho, Fuchu, Tokyo,  Japan.
authors.forename: Naoko
authors.initials: N
authors.lastname: Ohkama-Ohtsu
authors.affiliation: Biological Production Science, Tokyo University of Agriculture and Technology, Saiwaicho, Fuchu, Tokyo,  Japan.|Institute of Global Innovation Research, Tokyo University of Agriculture and Technology,  Saiwaicho, Fuchu, Tokyo, Japan.
authors.forename: Tadashi
authors.initials: T
authors.lastname: Yokoyama
authors.affiliation: Chemical Resources Laboratory, Tokyo Institute of Technology, Nagatsuta, Midori-ku, Yokohama, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Hara
authors.affiliation: Chemical Resources Laboratory, Tokyo Institute of Technology, Nagatsuta, Midori-ku, Yokohama, Japan.
authors.forename: Keisuke
authors.initials: K
authors.lastname: Yoshida
authors.affiliation: Chemical Resources Laboratory, Tokyo Institute of Technology, Nagatsuta, Midori-ku, Yokohama, Japan.
authors.forename: Toru
authors.initials: T
authors.lastname: Hisabori
authors.affiliation: Department of Horticultural Sciences, Vegetable and Fruit Improvement Center, Molecular and Environmental Plant Sciences Program, Texas A&M University, College Station, TX, USA.
authors.forename: Akihito
authors.initials: A
authors.lastname: Fukudome
authors.affiliation: Institute of Global Innovation Research, Tokyo University of Agriculture and Technology,  Saiwaicho, Fuchu, Tokyo, Japan.|Department of Horticultural Sciences, Vegetable and Fruit Improvement Center, Molecular and Environmental Plant Sciences Program, Texas A&M University, College Station, TX, USA.
authors.forename: Hisashi
authors.initials: H
authors.lastname: Koiwa
authors.affiliation: Department of Applied Biological Sciences, Tokyo University of Agriculture and Technology, Saiwaicho, Fuchu, Tokyo, Japan.
authors.forename: Hiromitsu
authors.initials: H
authors.lastname: Moriyama
authors.affiliation: Department of Applied Biological Sciences, Tokyo University of Agriculture and Technology, Saiwaicho, Fuchu, Tokyo, Japan.|Institute of Global Innovation Research, Tokyo University of Agriculture and Technology,  Saiwaicho, Fuchu, Tokyo, Japan.
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Takahashi
authors.affiliation: Department of Applied Biological Sciences, Tokyo University of Agriculture and Technology, Saiwaicho, Fuchu, Tokyo, Japan.|Institute of Global Innovation Research, Tokyo University of Agriculture and Technology,  Saiwaicho, Fuchu, Tokyo, Japan.
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Fukuhara
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant / Q000235:genetics / Q000502:physiology; D010084:Oxidation-Reduction; D010710:Phosphates / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000235:genetics / Q000502:physiology; D043244:Ribonuclease III / Q000235:genetics / Q000378:metabolism*; D013455:Sulfur / Q000172:deficiency / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D010710:Phosphates; D034741:RNA, Small Interfering; D013455:Sulfur; C504982:DCL4 protein, Arabidopsis; C519654:DCL3 protein, Arabidopsis; D043244:Ribonuclease III
keywords: Arabidopsis thaliana; DCL3; DCL4; Dicer; Phosphate; Redox