Skip Navigation



Nucleic Acids Research Advance Access published online on February 29, 2008
Nucleic Acids Research, doi:10.1093/nar/gkm1177
This Article
Right arrow Full Text Freely available
Right arrow Print PDF (10067K) Freely available
Right arrow Screen PDF (993K) Freely available
Right arrow Supplementary Data
Right arrowOA All Versions of this Article:
36/8/2476    most recent
gkm1177v1
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 Add to My Personal Archive
Right arrow Download to citation manager
Right arrow Commercial Re-use Guidelines
for Open Access NAR Content
Google Scholar
Right arrow Articles by Kopeina, G. S.
Right arrow Articles by Spirin, A. S.
PubMed
Right arrow PubMed Citation
Right arrow Articles by Kopeina, G. S.
Right arrow Articles by Spirin, A. S.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?

© 2008 The Author(s)
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/2.0/uk/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

RNA

Step-wise formation of eukaryotic double-row polyribosomes and circular translation of polysomal mRNA

Gelina S. Kopeina, Zhanna A. Afonina, Kira V. Gromova, Vladimir A. Shirokov, Victor D. Vasiliev and Alexander S. Spirin*

Institute of Protein Research, Russian Academy of Sciences, 142290 Pushchino, Moscow Region, Russia

*To whom correspondence should be addressed. Tel/Fax: +7 495 632 7871; Email: spirin{at}vega.protres.ru

Received September 7, 2007. Revised December 8, 2007. Accepted December 26, 2007.

The time course of polysome formation was studied in a long-term wheat germ cell-free translation system using sedimentation and electron microscopy techniques. The polysomes were formed on uncapped luciferase mRNA with translation-enhancing 5' and 3' UTRs. The formation of fully loaded polysomes was found to be a long process that required many rounds of translation and proceeded via several phases. First, short linear polysomes containing no more than six ribosomes were formed. Next, folding of these polysomes into short double-row clusters occurred. Subsequent gradual elongation of the clusters gave rise to heavy-loaded double-row strings containing up to 30–40 ribosomes. The formation of the double-row polysomes was considered to be equivalent to circularization of polysomes, with antiparallel halves of the circle being laterally stuck together by ribosome interactions. A slow exchange with free ribosomes and free mRNA observed in the double-row type polysomes, as well as the resistance of translation in them to AMP-PNP, provided evidence that most polysomal ribosomes reinitiate translation within the circularized polysomes without scanning of 5' UTR, while de novo initiation including 5' UTR scanning proceeds at a much slower rate. Removal or replacements of 5' and 3' UTRs affected the initial phase of translation, but did not prevent the formation of the double-row polysomes during translation.

Present address: Kira V. Gromova, Rudolf Virchow Center/DFG Research Center for Experimental Biomedicine of the University of Würzburg, 97078 Würzburg, Germany.


Add to CiteULike CiteULike   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us    What's this?




Disclaimer:
Please note that abstracts for content published before 1996 were created through digital scanning and may therefore not exactly replicate the text of the original print issues. All efforts have been made to ensure accuracy, but the Publisher will not be held responsible for any remaining inaccuracies. If you require any further clarification, please contact our Customer Services Department.