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

Published on: March 14, 2014

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Many OX PHOS and replication factor mRNAs target mitochondria through specific binding to the organelle surface,

Samit Adhya1, Milon Banik

  • 1CSIR-Indian Institute of Chemical Biology, 4 Raja S.C. Mullick Road, Kolkata 700 032, India. milon.banik123@gmail.com.

Journal of Genetics
|February 24, 2023
PubMed

Insights

Mitochondria bind specific messenger RNAs (mRNAs) for protein synthesis. This study reveals sequence-directed mRNA targeting to mitochondria, independent of translation, using new methods for faster identification.

Area of Science:

  • Molecular Biology
  • Cell Biology
  • Genetics

Background:

  • Nucleus-encoded mRNAs target mitochondria for oxidative phosphorylation protein synthesis.
  • Traditional methods for identifying mitochondrion-bound mRNAs (Mtb-RNAs) are laborious and biased towards co-translational import.
  • Sequence-directed mRNA targeting mechanisms remain underexplored.

Purpose of the Study:

  • To develop a rapid method for identifying and quantifying Mtb-RNAs in small cell numbers.
  • To investigate Mtb-RNA targeting mechanisms independent of polysomal status.
  • To explore sequence-directed mRNA targeting to mitochondria.

Main Methods:

  • Isolation of Mtb-RNAs from tissue-cultured cells.
  • Assay of Mtb-RNAs using endpoint or real-time polymerase chain reaction (RT-PCR).
  • Investigation of Mtb-RNA behavior under cycloheximide-induced polysome arrest and *in vitro* mitochondrial surface binding assays.
  • Formaldehyde crosslinking to stabilize mRNA-mitochondrion interactions.

Main Results:

  • Mtb-RNAs show differential responses to cycloheximide, suggesting potential artifacts with translation inhibitors.
  • Several Mtb-RNAs exhibit direct *in vitro* affinity for the mitochondrial surface, indicating RNA-binding protein involvement.
  • Formaldehyde crosslinking confirms and stabilizes mRNA-mitochondrion interactions.
  • Evidence supports sequence-directed targeting of mRNAs to mitochondria.

Conclusions:

  • A novel, rapid method for Mtb-RNA identification is established, overcoming limitations of previous techniques.
  • Mitochondrial mRNA targeting involves sequence-directed mechanisms, not solely co-translational import.
  • RNA-binding proteins likely play a crucial role in recognizing and binding specific mRNAs to the mitochondrial surface.

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