title: A dominant mutation in DCL1 suppresses the hyl1 mutant phenotype by promoting the processing of miRNA.
abstract: MicroRNAs (miRNAs) are sequence-specific negative regulators of gene expression generated by DICER-LIKE1 (DCL1) with the assistance of a double-stranded RNA-binding protein, HYPONASTIC LEAVES1 (HYL1), in Arabidopsis. To achieve a better understanding of miRNA biogenesis, we isolated hyl1 suppressors. Our genetic screening identified a novel semidominant mutation in DCL1 (dcl1-13), which causes an amino acid substitution of Glu-395 with Lys in the ATPase/DExH-box RNA helicase domain. This mutation confers significant restoration from the developmental abnormality and a reduction in the level of miRNA in the loss-of-function mutant of HYL1. However, the dcl1-13 single mutant, exhibiting a decreased number of leaves, showed a slight decrease in miRNA accumulation. Thus, the effect of the dcl1-13 mutation is HYL1 dependent: it promotes miRNA processing in the absence of HYL1, but conversely, impairs it in the presence of HYL1. Our results suggest significant roles of the helicase domain of DCL1, which remain unclear to date, possibly in relation with HYL1.
authors.affiliation: Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Meguro, Tokyo 153-8902, Japan.
authors.forename: Yuko
authors.initials: Y
authors.lastname: Tagami
authors.forename: Hiroyasu
authors.initials: H
authors.lastname: Motose
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Watanabe
mesh_terms: D019943:Amino Acid Substitution; D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D035683:MicroRNAs / Q000378:metabolism; D008958:Models, Molecular; D009154:Mutation; D010641:Phenotype; D018749:RNA, Plant / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D043244:Ribonuclease III / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D018797:Cell Cycle Proteins; C420966:HYL1 protein, Arabidopsis; D035683:MicroRNAs; D018749:RNA, Plant; D016601:RNA-Binding Proteins; C402383:DCL1 protein, Arabidopsis; D043244:Ribonuclease III