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Isolation of Translating Ribosomes Containing Peptidyl-tRNAs for Functional and Structural Analyses
Published on: February 26, 2011
General translational repression by activators of mRNA decapping
1Howard Hughes Medical Institute, Department of Molecular and Cellular Biology, University of Arizona, Tucson, Arizona 85721, USA.
Cell
|September 24, 2005
Summary
Dhh1p and Pat1p proteins repress translation and promote mRNA degradation in processing bodies. Their activity balances translation, influencing cellular control.
Area of Science:
- Molecular Biology
- Cell Biology
- Genetics
Background:
- Eukaryotic mRNA fate involves translation termination and assembly into messenger ribonucleoprotein (mRNP) complexes.
- These mRNPs accumulate in processing bodies (P bodies), which are key sites for mRNA decay and house degradation machinery.
- Understanding the transition from translation to mRNA decay is crucial for cellular regulation.
Purpose of the Study:
- To identify proteins involved in the transition of mRNA from translation to P body accumulation.
- To elucidate the roles of decapping activators Dhh1p and Pat1p in translational control and P body formation.
- To investigate the mechanism by which Dhh1p and Pat1p regulate mRNA fate.
Main Methods:
- Genetic analysis of yeast strains lacking or overexpressing Dhh1p and Pat1p.
- In vitro translation assays using Dhh1p.
- In vivo experiments involving inhibition of translational initiation.
Main Results:
- Dhh1p and Pat1p function as translational repressors and facilitators of P body formation.
- Strains deficient in Dhh1p and Pat1p exhibit defects in mRNA decapping, P body formation, and translational repression.
- Overexpression of Dhh1p or Pat1p leads to translational repression, P body formation, and growth arrest.
- Dhh1p and its human homolog RCK/p54 repress translation in vitro; this repression is bypassed by inhibiting translational initiation in vivo.
Conclusions:
- Dhh1p and Pat1p mediate a conserved mechanism of translational repression that targets mRNAs for decapping.
- This mechanism is integral to translational control and is competitively balanced with active translation.
- Shifting this balance is a fundamental aspect of regulating gene expression at the translational level.
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