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Methods to Classify Cytoplasmic Foci as Mammalian Stress Granules
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Methods to Classify Cytoplasmic Foci as Mammalian Stress Granules

Published on: May 12, 2017

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mRNA with Mammalian Codon Bias Accumulates in Yeast Mutants with Constitutive Stress Granules

Natalia V Kozlova1, Chantal Pichon1,2, A Rachid Rahmouni1

  • 1Centre de Biophysique Moléculaire, UPR 4301 du CNRS, Rue Charles Sadron, 45071 Orléans, France.

International Journal of Molecular Sciences
|February 16, 2020
PubMed

Insights

Constitutive stress granules and P bodies can stabilize mRNAs, but this study found that model mRNA accumulation in yeast mutants is independent of stress granule formation. Some stress granule pathways stabilize mRNA, but not all.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Genetics

Background:

  • Stress granules and P bodies are cytoplasmic structures involved in mRNA regulation during cellular stress.
  • Their formation mechanisms are diverse, with some stresses stabilizing mRNA by inhibiting deadenylation.
  • Previous studies identified yeast mutants with constitutive stress granules and elevated P bodies, but formation triggers remain unclear.

Purpose of the Study:

  • To investigate the accumulation of a model mRNA with mammalian codon bias in yeast mutants exhibiting constitutive stress granules and/or P bodies.
  • To determine the relationship between model mRNA accumulation and the formation of these cytoplasmic structures.
  • To explore the mechanisms underlying mRNA stabilization in these mutant contexts.

Main Methods:

  • Utilized yeast gene deletion mutants with constitutive stress granules and/or P bodies.
  • Introduced a model mRNA with mammalian codon bias into these mutants.
  • Quantified model mRNA levels using techniques like Northern blotting or RT-qPCR.
  • Analyzed the co-localization of model mRNA with stress granules and P bodies.

Main Results:

  • The model mRNA accumulated in *dcp2* and *xrn1* mutants, as well as in four mutants with constitutive stress granules overlapping with P bodies.
  • In contrast, eight other mutants with constitutive stress granules showed model mRNA downregulation or variable steady-state levels.
  • No direct targeting of the model mRNA to stress granules or P bodies was observed.
  • Model mRNA accumulation appeared linked to protection from the primary mRNA surveillance pathway.

Conclusions:

  • The accumulation of the model mRNA and the formation of constitutive stress granules are independent processes.
  • Only specific pathways that induce constitutive stress granule formation also lead to mRNA stabilization.
  • The findings suggest complex regulatory mechanisms governing mRNA fate in response to cellular stress and genetic perturbations.
Keywords:
Saccharomyces cerevisiaemRNA accumulationstress granules

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