MCB
Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
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 arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Latorre, P.
Right arrow Articles by Curran, J.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Latorre, P.
Right arrow Articles by Curran, J.

 Previous Article  |  Next Article 

Molecular and Cellular Biology, September 1998, p. 5021-5031, Vol. 18, No. 9
0270-7306/98/$04.00+0
Copyright © 1998, American Society for Microbiology. All rights reserved.

Sendai Virus Y Proteins Are Initiated by a Ribosomal Shunt

Patrizia Latorre, Daniel Kolakofsky, and Joseph Curran*

Department of Genetics and Microbiology, University of Geneva Medical School (CMU), CH1211 Geneva, Switzerland

Received 9 February 1998/Returned for modification 24 March 1998/Accepted 25 May 1998

The Sendai virus P/C mRNA expresses eight primary translation products by using a combination of ribosomal choice and cotranscriptional mRNA editing. The longest open reading frame (ORF) of the mRNA starts at AUG104 (the second initiation site) and encodes the 568-amino-acid P protein, an essential subunit of the viral polymerase. The first (ACG81), third (ATG114), fourth (ATG183), and fifth (ATG201) initiation sites are used to express a C-terminal nested set of polypeptides (collectively named the C proteins) in the +1 ORF relative to P, namely, C', C, Y1, and Y2, respectively. Leaky scanning accounts for translational initiation at the first three start sites (a non-ATG followed by ATGs in progressively stronger contexts). Consistent with this, changing ACG81/C' to ATG (GCCATG81G) abrogates expression from the downstream ATG104/P and ATG114/C initiation codons. However, expression of the Y1 and Y2 proteins remains normal in this background. We now have evidence that initiation from ATG183/Y1 and ATG201/Y2 takes place via a ribosomal shunt or discontinuous scanning. Scanning complexes appear to assemble at the 5' cap and then scan ca. 50 nucleotides (nt) of the 5' untranslated region before being translocated to an acceptor site at or close to the Y initiation codons. No specific donor site sequences are required, and translation of the Y proteins continues even when their start codons are changed to ACG. Curiously, ATG codons (in good contexts) in the P ORF, placed either 16 nt upstream of Y1, 29 nt downstream of Y2, or between the Y1 and Y2 codons, are not expressed even in the ACGY1/ACGY2 background. This indicates that ATG183/Y1 and ATG201/Y2 are privileged start sites within the acceptor site. Our observations suggest that the shunt delivers the scanning complex directly to the Y start codons.

* Corresponding author. Mailing address: Department of Genetics and Microbiology, University of Geneva Medical School (CMU), 9 Ave. Champel, CH1211 Geneva, Switzerland. Phone: 41-22-702-57.27. Fax: 41-22-346-72.37. E-mail: curran{at}cmu.unige.ch.

Molecular and Cellular Biology, September 1998, p. 5021-5031, Vol. 18, No. 9
0270-7306/98/$04.00+0
Copyright © 1998, American Society for Microbiology. All rights reserved.


This article has been cited by other articles:



Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
J. Bacteriol. J. Virol. Eukaryot. Cell
Microbiol. Mol. Biol. Rev. Clin. Vaccine Immunol. All ASM Journals

Copyright © 1998 by the American Society for Microbiology. All rights reserved.