title: AtRH57, a DEAD-box RNA helicase, is involved in feedback inhibition of glucose-mediated abscisic acid accumulation during seedling development and additively affects pre-ribosomal RNA processing with high glucose.
abstract: The Arabidopsis thaliana T-DNA insertion mutant rh57-1 exhibited hypersensitivity to glucose (Glc) and abscisic acid (ABA). The other two rh57 mutants also showed Glc hypersensitivity similar to rh57-1, strongly suggesting that the Glc-hypersensitive feature of these mutants results from mutation of AtRH57. rh57-1 and rh57-3 displayed severely impaired seedling growth when grown in Glc concentrations higher than 3%. The gene, AtRH57 (At3g09720), was expressed in all Arabidopsis organs and its transcript was significantly induced by ABA, high Glc and salt. The new AtRH57 belongs to class II DEAD-box RNA helicase gene family. Transient expression of AtRH57-EGFP (enhanced green fluorescent protein) in onion cells indicated that AtRH57 was localized in the nucleus and nucleolus. Purified AtRH57-His protein was shown to unwind double-stranded RNA independent of ATP in vitro. The ABA biosynthesis inhibitor fluridone profoundly redeemed seedling growth arrest mediated by sugar. rh57-1 showed increased ABA levels when exposed to high Glc. Quantitative real time polymerase chain reaction analysis showed that AtRH57 acts in a signaling network downstream of HXK1. A feedback inhibition of ABA accumulation mediated by AtRH57 exists within the sugar-mediated ABA signaling. AtRH57 mutation and high Glc conditions additively caused a severe defect in small ribosomal subunit formation. The accumulation of abnormal pre-rRNA and resistance to protein synthesis-related antibiotics were observed in rh57 mutants and in the wild-type Col-0 under high Glc conditions. These results suggested that AtRH57 plays an important role in rRNA biogenesis in Arabidopsis and participates in response to sugar involving Glc- and ABA signaling during germination and seedling growth.
authors.affiliation: Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, 40227, Taiwan.
authors.forename: Yi-Feng
authors.initials: YF
authors.lastname: Hsu
authors.forename: Yun-Chu
authors.initials: YC
authors.lastname: Chen
authors.forename: Yu-Chun
authors.initials: YC
authors.lastname: Hsiao
authors.forename: Bing-Jyun
authors.initials: BJ
authors.lastname: Wang
authors.forename: Shih-Yun
authors.initials: SY
authors.lastname: Lin
authors.forename: Wan-Hsing
authors.initials: WH
authors.lastname: Cheng
authors.forename: Guang-Yuh
authors.initials: GY
authors.lastname: Jauh
authors.forename: John J
authors.initials: JJ
authors.lastname: Harada
authors.forename: Co-Shine
authors.initials: CS
authors.lastname: Wang
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism*; D020816:Amino Acid Motifs; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development / Q000502:physiology; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D053487:DEAD-box RNA Helicases / Q000235:genetics* / Q000378:metabolism; D015870:Gene Expression; D018506:Gene Expression Regulation, Plant; D018525:Germination; D005947:Glucose / Q000378:metabolism; D008954:Models, Biological; D016254:Mutagenesis, Insertional; D010641:Phenotype; D010937:Plant Growth Regulators / Q000378:metabolism*; D030821:Plants, Genetically Modified; D012322:RNA Precursors / Q000235:genetics / Q000378:metabolism; D012335:RNA, Ribosomal / Q000235:genetics / Q000378:metabolism*; D012270:Ribosomes / Q000235:genetics / Q000378:metabolism; D036226:Seedlings / Q000201:enzymology / Q000235:genetics / Q000254:growth & development; D012639:Seeds / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D015398:Signal Transduction
chemical_list: D029681:Arabidopsis Proteins; D010937:Plant Growth Regulators; D012322:RNA Precursors; D012335:RNA, Ribosomal; D000040:Abscisic Acid; D053487:DEAD-box RNA Helicases; C000593715:RH57 protein, Arabidopsis; D005947:Glucose
keywords: Arabidopsis thaliana seeds; RNA helicase; abscisic acid; glucose-hypersensitive; rRNA biogenesis; seedling growth