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Visualization of Endoplasmic Reticulum Localized mRNAs in Mammalian Cells
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Visualization of Endoplasmic Reticulum-Associated mRNA in Mammalian Cells

Jingze J Wu1, Alexander F Palazzo2

  • 1Department of Biochemistry, University of Toronto, Toronto, ON, Canada.

Methods in Molecular Biology (Clifton, N.J.)
|July 26, 2020
PubMed

Insights

This study reveals that a portion of all messenger RNAs (mRNAs), not just those for secretory proteins, bind to the endoplasmic reticulum (ER) via ribosomes. This finding clarifies the distribution of mRNAs within eukaryotic cells.

Area of Science:

  • Molecular Biology
  • Cell Biology
  • Genetics

Background:

  • Most eukaryotic messenger RNAs (mRNAs) encoding secretory or membrane proteins are translated on the endoplasmic reticulum (ER).
  • It remains debated whether all mRNAs, irrespective of their encoded protein type, associate with the ER at low levels.

Purpose of the Study:

  • To develop a method for visualizing ER-associated mRNAs in cells.
  • To determine if non-secretory mRNAs also associate with the ER.

Main Methods:

  • Developed a protocol using single-molecule fluorescence in situ hybridization (smFISH).
  • Applied smFISH to visualize ER-associated mRNAs in tissue culture cells.

Main Results:

  • Established a protocol to visualize ER-associated mRNAs.
  • Demonstrated that a subset of all mRNAs, including those for cytosolic proteins, are associated with the ER.
  • Confirmed this association is ribosome-dependent.

Conclusions:

  • A fraction of all cellular mRNAs are associated with the ER.
  • This ER association is dependent on ribosomes.
  • The findings challenge previous assumptions about mRNA localization and translation.
Keywords:
Cell extractionEndoplasmic reticulumRibosomesSingle-molecule localizationmRNA

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