Sugar-inducible expression of the nucleolin-1 gene of Arabidopsis thaliana and its role in ribosome synthesis, growth and development
Article first published online: 7 FEB 2007
The Plant Journal
Volume 49, Issue 6, pages 1053–1063, March 2007
How to Cite
Kojima, H., Suzuki, T., Kato, T., Enomoto, K.-i., Sato, S., Kato, T., Tabata, S., Sáez-Vasquez, J., Echeverría, M., Nakagawa, T., Ishiguro, S. and Nakamura, K. (2007), Sugar-inducible expression of the nucleolin-1 gene of Arabidopsis thaliana and its role in ribosome synthesis, growth and development. The Plant Journal, 49: 1053–1063. doi: 10.1111/j.1365-313X.2006.03016.x
- Issue published online: 7 FEB 2007
- Article first published online: 7 FEB 2007
- Received 23 July 2006; revised 21 October 2006; accepted 10 November 2006.
- ribosome synthesis;
- ribosomal protein genes;
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.