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Isolation of mRNAs Associated with Yeast Mitochondria to Study Mechanisms of Localized Translation
14:44

Isolation of mRNAs Associated with Yeast Mitochondria to Study Mechanisms of Localized Translation

Published on: March 14, 2014

Tom20 mediates localization of mRNAs to mitochondria in a translation-dependent manner

Erez Eliyahu1, Lilach Pnueli, Daniel Melamed

  • 1Department of Biology, Technion-Israel Institute of Technology, Haifa 32000, Israel.

Molecular and Cellular Biology
|October 28, 2009
PubMed

Insights

Mitochondrial protein mRNA localization to mitochondria is facilitated by the translocase of the outer membrane (TOM) complex, specifically Tom20p, and potentially Puf3p. This interaction ensures efficient mitochondrial protein transport.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Genetics

Background:

  • Messenger RNAs (mRNAs) encoding mitochondrial proteins are found near mitochondria, likely for efficient protein transport.
  • The translocase of the mitochondrial outer membrane (TOM) complex is a potential mediator of this mRNA localization during translation.

Purpose of the Study:

  • To investigate the role of the major mitochondrial import receptor, Tom20, in the association of mRNAs with mitochondria.
  • To explore the combined roles of Tom20 and Puf3p in mRNA localization and mitochondrial function.

Main Methods:

  • Isolated mitochondrial fractions from yeast cells lacking Tom20 (tom20 Δ) and wild-type cells.
  • Compared mRNA repertoires using DNA microarrays.
  • Constructed and analyzed a tom20 Δ puf3 Δ double-knockout strain.

Main Results:

  • Most mitochondrial protein mRNAs showed reduced association with mitochondria in tom20 Δ cells, with varying degrees of decrease.
  • Optimal association of Tom20 target mRNAs requires both translating ribosomes and the mitochondrial targeting signal.
  • The tom20 Δ puf3 Δ double-knockout strain exhibited growth defects, and some mRNA mislocalization effects were more pronounced than in the tom20 Δ strain.

Conclusions:

  • Tom20p interacts with translated mitochondrial targeting sequences to mediate mRNA association with mitochondria.
  • Puf3p may assist Tom20p in this mRNA localization process.
  • This study reveals a mechanism for large-scale mRNA association with mitochondria involving Tom20p and potentially Puf3p.

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