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Modeling Neuronal Death and Degeneration in Mouse Primary Cerebellar Granule Neurons
Published on: November 6, 2017
Organelles do not colocalize with mRNA granules in post-ischemic neurons
J T Jamison1, J J Szymanski, D J Degracia
1Department of Physiology, Wayne State University School of Medicine, Detroit, MI 48201, USA.
Neuroscience
|October 8, 2011
Summary
Researchers investigated mRNA granules in brain cells after ischemia. These granules, linked to translation arrest, do not associate with major organelles or a known protein pathway, suggesting a novel mechanism in neuronal response.
Area of Science:
- Neuroscience
- Molecular Biology
- Cell Biology
Background:
- Global brain ischemia and reperfusion induce neuronal translation arrest.
- This arrest is reversible in surviving neurons but irreversible in vulnerable ones.
- Previously identified mRNA granules correlate with translation arrest in reperfused neurons.
Purpose of the Study:
- To further characterize the composition and localization of mRNA granules in reperfused neurons.
- To determine the relationship between mRNA granules and cellular organelles or specific protein pathways.
Main Methods:
- Colocalization studies using fluorescent in situ hybridization for poly(A) mRNAs.
- Immunofluorescence histochemistry for organelle markers and mRNA-binding proteins (e.g., HuR).
- RNA immunoprecipitation of HuR from cytoplasmic fractions.
Main Results:
- mRNA granules did not colocalize with markers for endoplasmic reticulum, Golgi apparatus, mitochondria, or cytoskeletal elements.
- No colocalization was observed with 60S ribosomal subunits or HuR ligands APRIL and pp32.
- mRNA granules colocalized with the neuronal marker NeuN.
- RNA immunoprecipitation isolated hsp70 mRNA, indicating soluble mRNA granules.
Conclusions:
- The results exclude several major organelle systems from direct involvement in mRNA granule function.
- A known HuR pathway is also not directly implicated in the formation or function of these granules.
- mRNA granules represent a distinct cellular structure potentially involved in regulating translation during neuronal stress.
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