In:
eLife, eLife Sciences Publications, Ltd, Vol. 5 ( 2016-10-01)
Abstract:
Molecular machines called ribosomes read the genetic instructions in an mRNA molecule and then translate them to make proteins. However, cells do not translate all of the template mRNAs that they have available into proteins; instead they have a number of ways to block the process to control when certain proteins are made. In budding yeast, the mRNA that codes for a protein called Hac1 is always present in the cell but the protein is normally not detected. The Hac1 protein is responsible for helping the cell deal with certain types of stress, so it only accumulates when the cell is experiencing such stresses. The mRNA that encodes Hac1 (referred to as HAC1 mRNA) contains a sequence called an intron. These sequences are normally cut out of mRNAs before they are read by the ribosome. However, the intron in the HAC1 mRNA is unusual, because it is only removed when cells are subjected to stress. The rest of the time, this intron serves to block the production of Hac1 through a poorly understood mechanism. Now, Di Santo et al. show the HAC1 mRNA uses two strategies to keep itself fully repressed—both of which involve its intron. One strategy relies on a structure formed in the HAC1 mRNA that prevents ribosomes from starting translation in the first place. However, this block is occasionally bypassed, causing some Hac1 protein to be produced when it should not be. To deal with this, the Hac1 protein that is produced contains a short protein sequence, encoded by the intron, that targets this unneeded protein for degradation. These two strategies together comprise a “fail-safe” mechanism to completely repress the HAC1 mRNA. Following on from these findings, it will be important to determine whether other mRNAs – both in budding yeast and in other species including humans – use a similar fail-safe strategy to block proteins from being made when they should not be.
Type of Medium:
Online Resource
ISSN:
2050-084X
DOI:
10.7554/eLife.20069.001
DOI:
10.7554/eLife.20069.002
DOI:
10.7554/eLife.20069.003
DOI:
10.7554/eLife.20069.004
DOI:
10.7554/eLife.20069.005
DOI:
10.7554/eLife.20069.006
DOI:
10.7554/eLife.20069.007
DOI:
10.7554/eLife.20069.008
DOI:
10.7554/eLife.20069.009
DOI:
10.7554/eLife.20069.010
DOI:
10.7554/eLife.20069.011
DOI:
10.7554/eLife.20069.012
DOI:
10.7554/eLife.20069.013
DOI:
10.7554/eLife.20069.014
DOI:
10.7554/eLife.20069.015
DOI:
10.7554/eLife.20069.016
DOI:
10.7554/eLife.20069.017
DOI:
10.7554/eLife.20069.018
DOI:
10.7554/eLife.20069.023
DOI:
10.7554/eLife.20069.024
Language:
English
Publisher:
eLife Sciences Publications, Ltd
Publication Date:
2016
detail.hit.zdb_id:
2687154-3
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