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Journal of Bacteriology, August 2001, p. 4477-4483, Vol. 183, No. 15
Department of Molecular Microbiology and
Biotechnology, Tel-Aviv University, Ramat Aviv 69978, Israel
Received 18 September 2000/Accepted 15 May 2001
The eukaryotic translation initiation factor 4E (eIF4E)
interacts with the mRNA 5' cap structure (m7GpppX)
and is essential for the appropriate translation of the vast
majority of eukaryotic mRNAs. Most studies of the yeast
Saccharomyces cerevisiae CDC33 gene product, eIF4E, have
been carried out with logarithmically growing cells, and little is
known about its role in starved, nonproliferating cells that enter the
stationary phase (SP). It has previously been found that the rate of
translation in SP cells is more than 2 orders of magnitude lower than
it is in dividing yeast cells. Here we show that this low rate of
translation is essential for maintaining the viability of starved
yeast cells that enter SP. Specifically, starved cells whose eIF4A is
inactive or treated with cycloheximide rapidly lose viability.
Moreover, after heat inactivation of the cdc33
temperature-sensitive product, the synthesis of most proteins is
abolished and only a small group of proteins is still produced.
Unexpectedly, starved cdc33 mutant cells whose eIF4E is
inactive and which therefore fail to synthesize the bulk of their
proteins remain viable for long periods of time, indistinguishable from
their isogenic wild-type counterparts. Taken together, our results
indicate that eIF4E-independent translation is necessary and sufficient
for survival of yeast cells during long periods of starvation.
0021-9193/01/$04.00+0 DOI: 10.1128/JB.183.15.4477-4483.2001
Copyright © 2001, American Society for Microbiology. All rights reserved.
Eukaryotic Translation Initiation Factor 4E-Dependent Translation
Is Not Essential for Survival of Starved Yeast Cells
*
Corresponding author. Mailing address: Department of
Molecular Microbiology and Biotechnology, Tel-Aviv University, Ramat Aviv 69978, Israel. Phone: 972-36409030. Fax: 972-25334140. E-mail: lcchoder{at}post.tau.ac.il.
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