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Sugar‐inducible expression of the nucleolin‐1 gene of Arabidopsis thaliana and its role in ribosome synthesis, growth and development
Author(s) -
Kojima Hisae,
Suzuki Takamasa,
Kato Takenori,
Enomoto Kenichi,
Sato Shusei,
Kato Tomohiko,
Tabata Satoshi,
SáezVasquez Julio,
Echeverría Manuel,
Nakagawa Tsuyoshi,
Ishiguro Sumie,
Nakamura Kenzo
Publication year - 2007
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/j.1365-313x.2006.03016.x
Subject(s) - nucleolin , ribosome biogenesis , biology , nucleolus , gene , ribosome , arabidopsis , gene expression , ribosomal protein , mutant , microbiology and biotechnology , meristem , protein biosynthesis , biochemistry , rna , cytoplasm
Summary 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 m m 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.