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Mitochondrial RNA granules are fluid condensates positioned by membrane dynamics
Timo Rey1, Sofia Zaganelli2,3, Emilie Cuillery
1Laboratory of Experimental Biophysics, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland. timo.rey@epfl.ch.
Nature Cell Biology
|September 29, 2020
Summary
Mitochondrial RNA granules (MRGs) are fluid compartments within mitochondria. These dynamic structures, crucial for gene expression, are dispersed via mitochondrial membrane dynamics.
Area of Science:
- Cell Biology
- Mitochondrial Biology
- Molecular Biology
Background:
- Mitochondria possess their own genetic material and protein synthesis machinery.
- Mitochondrial RNA granules (MRGs) are sub-compartments in the mitochondrial matrix, implicated in gene expression regulation.
- The structural and dynamic properties of MRGs are not well understood.
Purpose of the Study:
- To investigate the internal architecture and dynamic properties of mitochondrial RNA granules (MRGs).
- To understand the role of MRGs in mitochondrial dynamics and gene expression.
Main Methods:
- Fluorescence super-resolution localization microscopy
- Correlative electron microscopy
- Live-cell super-resolution structured illumination microscopy
- Fluorescence recovery after photobleaching
Main Results:
- MRGs exhibit an ultrastructure of compacted RNA within a protein cloud.
- MRGs display fluid condensate properties, including rapid component exchange and fusion.
- MRG fusion is linked to mitochondrial remodeling, and their distribution is influenced by mitochondrial fission/fusion dynamics.
Conclusions:
- MRGs are nanoscale fluid compartments within the mitochondrial matrix.
- Mitochondrial membrane dynamics play a key role in the dispersion of MRGs.
- MRGs are integral to mitochondrial function and organization.
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