title: Sugar-inducible expression of the nucleolin-1 gene of Arabidopsis thaliana and its role in ribosome synthesis, growth and development.
abstract: Animal and yeast nucleolin function as global regulators of ribosome synthesis, and their expression is tightly linked to cell proliferation. Although Arabidopsis contains two genes for nucleolin, AtNuc-L1 is the predominant if not only form of the protein found in most tissues, and GFP-AtNuc-L1 fusion proteins were targeted to the nucleolus. Expression of AtNuc-L1 was strongly induced by sucrose or glucose but not by non-metabolizable mannitol or 2-deoxyglucose. Sucrose also caused enhanced expression of genes for subunits of C/D and H/ACA small nucleolar ribonucleoproteins, as well as a large number of genes for ribosomal proteins (RPs), suggesting that carbohydrate availability regulates de novo ribosome synthesis. In sugar-starved cells, induction of AtNuc-L1 occurred with 10 mM glucose, which seemed to be a prerequisite for resumption of growth. Disruption of AtNuc-L1 caused an increased steady-state level of pre-rRNA relative to mature 25S rRNA, and resulted in various phenotypes that overlap those reported for several RP gene mutants, including a reduced growth rate, prolonged lifetime, bushy growth, pointed leaf, and defective vascular patterns and pod development. These results suggest that the rate of ribosome synthesis in the meristem has a strong impact not only on the growth but also the structure of plants. The AtNuc-L1 disruptant exhibited significantly reduced sugar-induced expression of RP genes, suggesting that AtNuc-L1 is involved in the sugar-inducible expression of RP genes.
authors.affiliation: Laboratory of Biochemistry, Department of Biological Functions and Mechanisms, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa, Nagoya 464-8601, Japan.
authors.forename: Hisae
authors.initials: H
authors.lastname: Kojima
authors.forename: Takamasa
authors.initials: T
authors.lastname: Suzuki
authors.forename: Takenori
authors.initials: T
authors.lastname: Kato
authors.forename: Ken-ichi
authors.initials: K
authors.lastname: Enomoto
authors.forename: Shusei
authors.initials: S
authors.lastname: Sato
authors.forename: Tomohiko
authors.initials: T
authors.lastname: Kato
authors.forename: Satoshi
authors.initials: S
authors.lastname: Tabata
authors.forename: Julio
authors.initials: J
authors.lastname: Sáez-Vasquez
authors.forename: Manuel
authors.initials: M
authors.lastname: Echeverría
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Nakagawa
authors.forename: Sumie
authors.initials: S
authors.lastname: Ishiguro
authors.forename: Kenzo
authors.initials: K
authors.lastname: Nakamura
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000502:physiology; D018506:Gene Expression Regulation, Plant / Q000502:physiology*; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D012270:Ribosomes / Q000378:metabolism*; D013395:Sucrose; D000097796:Nucleolin
chemical_list: D010750:Phosphoproteins; D016601:RNA-Binding Proteins; D013395:Sucrose; D000097796:Nucleolin