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| Status |
Public on Jan 11, 2022 |
| Title |
eIF3 and its mRNA-entry-channel arm contribute to the recruitment of mRNAs with long 5'-untranslated regions |
| Organism |
Saccharomyces cerevisiae |
| Experiment type |
Expression profiling by high throughput sequencing
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| Summary |
Translation initiation in eukaryotes is multi-step pathway and the most regulated phase of translation. Eukaryotic initiation factor 3 is the largest and most complex of the translation initiation factors, and it contributes to events throughout the initiation pathway. In particular, eIF3 appears to play critical roles in mRNA recruitment. More recently, eIF3 has been implicated in driving the selective translation of specific classes of mRNAs. However, unraveling the mechanism of these diverse contributions — and disentangling the roles of the individual subunits of the eIF3 complex — remains challenging. We employed ribosome profiling of budding yeast cells expressing two distinct mutations targeting the eIF3 complex. These mutations either disrupt the entire complex or subunits positioned near the mRNA-entry channel of the ribosome which appear to relocate during or in response to mRNA binding and start-codon recognition. Disruption of either the entire eIF3 complex or specific targeting of these subunits affects mRNAs with long 5’-untranslated regions and whose translation is more dependent on eIF4A, eIF4B, and Ded1 but less dependent on eIF4G, eIF4E, and PABP. Disruption of the entire eIF3 complex further affects mRNAs involved in mitochondrial processes and with structured 5’-untranslated regions. Comparison of the suite of mRNAs most sensitive to both mutations with those uniquely sensitive to disruption of the entire complex sheds new light on the specific roles of individual subunits of the eIF3 complex.
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| Overall design |
We investigated the effects of disruption of the entire eIF3 complex or its mRNA-entry-channel arm on the translational efficiency (TE) of individual mRNAs across the transcriptome. This study includes 16 samples: 8 mRNA-seq samples and 8 ribosome footprint profiling samples, obtained from biological replicates of S. cerevisiae strains expressing either temperature-sensitive degron alleles of eIF3a and eIF3ab (eIF3a/b Degron) or a specific mutation of the eIF3i subunit (eIF3i DDKK), as well as isogenic wild-type strains for each. All strains were grown initially under permissive conditions prior to shifting to restrictive conditions for a duration resulting in approximately 80-90% reduction in global translational levels in each mutant strain.
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| Contributor(s) |
Stanciu A, Luo J, Funes L, Galbokke Hewage S, Echeverría Aitken C |
| Citation(s) |
35087868 |
| Submission date |
Dec 09, 2021 |
| Last update date |
Feb 02, 2022 |
| Contact name |
Colin Echeverría Aitken |
| E-mail(s) |
caitken@vassar.edu
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| Organization name |
Vassar College
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| Street address |
124 Raymond Ave., Box 731
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| City |
Poughkeepsie |
| State/province |
NY |
| ZIP/Postal code |
12604 |
| Country |
USA |
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| Platforms (1) |
| GPL17342 |
Illumina HiSeq 2500 (Saccharomyces cerevisiae) |
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| Samples (16)
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| Relations |
| BioProject |
PRJNA787625 |
| SRA |
SRP350144 |
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