JB
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 Withey, J.
Right arrow Articles by Friedman, D.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Withey, J.
Right arrow Articles by Friedman, D.

 Previous Article  |  Next Article 

Journal of Bacteriology, April 1999, p. 2148-2157, Vol. 181, No. 7
0021-9193/99/$04.00+0
Copyright © 1999, American Society for Microbiology. All rights reserved.

Analysis of the Role of trans-Translation in the Requirement of tmRNA for lambda immP22 Growth in Escherichia coli

Jeffrey Withey1 and David Friedman1,2,*

Graduate Program in Cellular and Molecular Biology1 and Department of Microbiology and Immunology,2 University of Michigan, Ann Arbor, Michigan 48109-0620

Received 8 January 1998/Accepted 14 January 1999

The small, stable RNA molecule encoded by ssrA, known as tmRNA or 10Sa RNA, is required for the growth of certain hybrid lambda immP22 phages in Escherichia coli. tmRNA has been shown to tag partially synthesized proteins for degradation in vivo by attaching a short peptide sequence, encoded by tmRNA, to the carboxyl termini of these proteins. This tag sequence contains, at its C terminus, an amino acid sequence that is recognized by cellular proteases and leads to degradation of tagged proteins. A model describing this function of tmRNA, the trans-translation model (K. C. Keiler, P. R. Waller, and R. T. Sauer, Science 271:990-993, 1996), proposes that tmRNA acts first as a tRNA and then as a mRNA, resulting in release of the original mRNA template from the ribosome and translocation of the nascent peptide to tmRNA. Previous work from this laboratory suggested that tmRNA may also interact specifically with DNA-binding proteins, modulating their activity. However, more recent results indicate that interactions between tmRNA and DNA-binding proteins are likely nonspecific. In light of this new information, we examine the effects on lambda immP22 growth of mutations eliminating activities postulated to be important for two different steps in the trans-translation model, alanine charging of tmRNA and degradation of tagged proteins. This mutational analysis suggests that, while charging of tmRNA with alanine is essential for lambda immP22 growth in E. coli, degradation of proteins tagged by tmRNA is required only to achieve optimal levels of phage growth. Based on these results, we propose that trans-translation may have two roles, the primary role being the release of stalled ribosomes from their mRNA template and the secondary role being the tagging of truncated proteins for degradation.

* Corresponding author. Mailing address: Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI 48109-0620. Phone: (734) 763-3142. Fax: (734) 764-3562. E-mail: davidfri{at}umich.edu.

Journal of Bacteriology, April 1999, p. 2148-2157, Vol. 181, No. 7
0021-9193/99/$04.00+0
Copyright © 1999, American Society for Microbiology. All rights reserved.


This article has been cited by other articles:



Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
Appl. Environ. Microbiol. Infect. Immun. Eukaryot. Cell
Mol. Cell. Biol. J. Virol. Microbiol. Mol. Biol. Rev.
ALL ASM JOURNALS

Copyright © 1999 by the American Society for Microbiology. All rights reserved.