Plant Physiol. Drug Metab Dispos
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
QUICK SEARCH:   [advanced]


     

Plant Physiology Preview
Published on March 5, 2008; 10.1104/pp.107.111799

OPEN ACCESS ARTICLE
This Article
Free via Open Access: OA
Right arrow Full Text (Plant Physiology Preview (PDF))
Right arrow Supplemental Data
Right arrowOA All Versions of this Article:
147/1/128    most recent
pp.107.111799v1
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Google Scholar
Right arrow Articles by Degenhardt, R. F.
Right arrow Articles by Bonham-Smith, P. C.
PubMed
Right arrow PubMed Citation
Right arrow Articles by Degenhardt, R. F.
Right arrow Articles by Bonham-Smith, P. C.
Agricola
Right arrow Articles by Degenhardt, R. F.
Right arrow Articles by Bonham-Smith, P. C.

Received October 26, 2007
Accepted February 26, 2008

Arabidopsis ribosomal proteins RPL23aA and -B are differentially targeted to the nucleolus and are disparately required for normal development

Rory F. Degenhardt * and Peta C. Bonham-Smith

Department of Biology, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada

* Corresponding author; email: rfd014{at}mail.usask.ca.

Protein synthesis is catalyzed by the ribosome, a two subunit enzyme comprised of four rRNAs and, in Arabidopsis (Arabidopsis thaliana), 81 ribosomal proteins (r-proteins). Plant r-protein genes exist as families of multiple expressed members, yet only one r-protein from each family is incorporated into any given ribosome, suggesting that many r-protein genes may be functionally redundant or development/tissue/stress specific. Here we characterized the localization and gene silencing phenotypes of a large subunit r-protein family, RPL23a, containing two expressed genes (-A and -B). Live cell imaging of RPL23aA and -B in tobacco (Nicotiana tabacum) with a C-terminal fluorescent-protein tag demonstrated that both isoforms accumulated in the nucleolus, however only RPL23aA was targeted to the nucleolus with an N-terminal fluorescent protein tag, suggesting divergence in targeting efficiency of localization signals. Independent knockdowns of endogenous RPL23aA and -B transcript levels using RNA interference (RNAi) determined that a RPL23aB knockdown did not alter plant growth or development. Conversely, a knockdown of RPL23aA produced a pleiotropic phenotype characterized by growth retardation, irregular leaf and root morphology, abnormal phyllotaxy and vasculature, and loss of apical dominance. Comparison to other mutants suggests that the phenotype results from reduced ribosome biogenesis, and we postulate a link between biogenesis, microRNA-target degradation and maintenance of auxin homeostasis. An additional RNAi construct that coordinately silenced both RPL23aA and -B demonstrated that this family is essential for viability.






HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
ASPB Publications PLANT PHYSIOLOGY THE PLANT CELL
Copyright © 2008 by the American Society of Plant Biologists