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Translation in Saccharomyces cerevisiae: initiation factor 4E-dependent cell-free system
M Altmann1, N Sonenberg, H Trachsel
1Institut für Biochemie und Molekularbiologie, Universität Bern, Switzerland.
Molecular and Cellular Biology
|October 1, 1989
Summary
Researchers mutated the translation initiation factor 4E (eIF-4E) gene in yeast. Mutated eIF-4E impaired protein synthesis, showing its essential role in yeast cell function.
Area of Science:
- Molecular Biology
- Yeast Genetics
Background:
- Translation initiation factor 4E (eIF-4E) is crucial for protein synthesis.
- Understanding eIF-4E function requires studying its mutations.
Purpose of the Study:
- To investigate the effects of mutated eIF-4E on Saccharomyces cerevisiae.
- To identify temperature-sensitive mutations in the eIF-4E gene.
Main Methods:
- Random in vitro mutagenesis of the eIF-4E gene.
- Introduction of mutated genes into yeast strains with a regulatable wild-type copy.
- Identification of temperature-sensitive mutants via replica plating.
- Analysis of protein synthesis and translation in mutant strains.
Main Results:
- A temperature-sensitive yeast strain (4-2) with two point mutations in eIF-4E was identified.
- At 37°C, [35S]methionine incorporation decreased to 15% of wild-type levels in strain 4-2.
- Cell-free translation systems from strain 4-2 showed dependence on exogenous eIF-4E for certain mRNAs.
Conclusions:
- Mutations in eIF-4E significantly impact protein synthesis in yeast.
- The identified mutations affect the efficiency of translation for specific mRNAs.
- eIF-4E plays a vital, though not universally required, role in mRNA translation.