Related Experiment Video
Updated: May 13, 2026
09:33
Methods to Classify Cytoplasmic Foci as Mammalian Stress Granules
Published on: May 12, 2017
GRSF1 regulates RNA processing in mitochondrial RNA granules.
Alexis A Jourdain1, Mirko Koppen, Mateusz Wydro
1Department of Cell Biology, University of Geneva, 30 Quai Ernest-Ansermet, 1211 Genève 4, Switzerland.
Cell Metabolism
|March 12, 2013
Summary
Mitochondria contain novel RNA granules, termed mitochondrial RNA granules, where G-rich sequence factor 1 (GRSF1) protein processes RNA. This discovery reveals new insights into mitochondrial gene expression and function.
Area of Science:
- Mitochondrial biology
- Molecular cell biology
- RNA biology
Background:
- Compartmentalization within the mitochondrial matrix is poorly understood.
- G-rich sequence factor 1 (GRSF1) is an RNA binding protein previously localized to the cytosol.
Purpose of the Study:
- To investigate the localization and function of GRSF1 within mitochondria.
- To identify novel structures involved in mitochondrial RNA processing.
Main Methods:
- Immunofluorescence microscopy to visualize GRSF1 foci.
- Co-immunoprecipitation to assess protein interactions.
- RNA analysis to evaluate processing intermediates and products.
Main Results:
- An isoform of GRSF1 accumulates in discrete foci within the mitochondrial matrix.
- These foci contain nascent mitochondrial RNA and RNase P, an RNA processing enzyme.
- GRSF1 interacts with RNase P and is essential for processing mitochondrial RNA precursors, including tRNA-less precursors.
- GRSF1 depletion leads to abnormal RNA cleavage, reduced expression of mitochondrially encoded proteins, and mitochondrial dysfunction.
Conclusions:
- GRSF1 and RNase P form large ribonucleoprotein structures, termed mitochondrial RNA granules, within the mitochondrial matrix.
- These granules serve as sites for the processing of primary mitochondrial RNA transcripts.
- Mitochondrial RNA granules play a critical role in maintaining mitochondrial gene expression and function.
More Related Videos
Related Concept Videos
02:53Ribosomal RNA Synthesis
Ribosome synthesis is a highly complex and coordinated process involving more than 200 assembly factors. The synthesis and processing of ribosomal components occurs not only in the nucleolus but also in the nucleoplasm and the cytoplasm of eukaryotic cells.
Ribosome biogenesis begins with the synthesis of 5S and 45S pre-rRNAs by distinct RNA polymerases. The primary transcripts are extensively processed and modified before they are bound and folded by ribosomal proteins and assembly factors,...
Ribosome biogenesis begins with the synthesis of 5S and 45S pre-rRNAs by distinct RNA polymerases. The primary transcripts are extensively processed and modified before they are bound and folded by ribosomal proteins and assembly factors,...
02:53Ribosomal RNA Synthesis
Ribosome synthesis is a highly complex and coordinated process involving more than 200 assembly factors. The synthesis and processing of ribosomal components occurs not only in the nucleolus but also in the nucleoplasm and the cytoplasm of eukaryotic cells.
Ribosome biogenesis begins with the synthesis of 5S and 45S pre-rRNAs by distinct RNA polymerases. The primary transcripts are extensively processed and modified before they are bound and folded by ribosomal proteins and assembly factors,...
Ribosome biogenesis begins with the synthesis of 5S and 45S pre-rRNAs by distinct RNA polymerases. The primary transcripts are extensively processed and modified before they are bound and folded by ribosomal proteins and assembly factors,...
01:23Transcriptional Regulation: Riboswitches
Riboswitches are RNA elements that regulate gene expression by altering their secondary structures in response to specific effector molecules. These elements, located in the leader regions of certain mRNAs, act as transcriptional regulators by toggling between alternative conformations to control downstream gene expression. Riboswitch-mediated regulation is a precise mechanism for modulating biosynthetic pathways, as exemplified by the riboflavin biosynthesis pathway in Bacillus...
01:23Regulation of Expression at Multiple Steps
The gene expression in cells is regulated at different stages: (i) transcription, (ii) RNA processing, (iii) RNA localization, and (iv) translation. Transcriptional regulation is mediated by regulatory proteins such as transcription factors, activators, or repressors—these control gene expression by initiating or inhibiting the transcription of genes. Once a precursor or pre-mRNA is produced, it undergoes post-transcriptional modification, including 5' capping, splicing, and the addition of a...
02:23RNA Editing
RNA editing is a post-transcriptional modification where a precursor mRNA (pre-mRNA) nucleotide sequence is changed by base insertion, deletion, or modification. The extent of RNA editing varies from a few hundred bases, in mitochondrial DNA of trypanosomes, to a just single base, in nuclear genes of mammals. Even a single base change in the pre-mRNA can convert a codon for one amino acid into the codon for another amino acid or a stop codon. This type of re-coding can significantly affect the...
02:30siRNA - Small Interfering RNAs
Small interfering RNAs, or siRNAs, are short regulatory RNA molecules that can silence genes post-transcriptionally, as well as the transcriptional level in some cases. siRNAs are important for protecting cells against viral infections and silencing transposable genetic elements.
In the cytoplasm, siRNA is processed from a double-stranded RNA, which comes from either endogenous DNA transcription or exogenous sources like a virus. This double-stranded RNA is then cleaved by the ATP-dependent...
In the cytoplasm, siRNA is processed from a double-stranded RNA, which comes from either endogenous DNA transcription or exogenous sources like a virus. This double-stranded RNA is then cleaved by the ATP-dependent...