Related Experiment Videos
Ribosomal-type ribonucleic acid from rodent mitochondria
The Biochemical Journal
|December 1, 1970
Summary
Mitochondria contain distinct RNA molecules, including 15S and 13S RNA from rat liver and 15S and 12.5S RNA from mouse L cells, characterized by specific nucleotide compositions and electrophoretic mobilities.
Area of Science:
- Mitochondrial biology
- Molecular biology
- RNA biochemistry
Background:
- Mitochondria possess their own genetic material, distinct from nuclear DNA.
- Characterizing mitochondrial RNA (mtRNA) is crucial for understanding mitochondrial function and disease.
- Previous studies have identified various RNA species within mitochondria, but their precise nature and origins require further elucidation.
Purpose of the Study:
- To isolate and characterize RNA from purified rat liver mitochondria.
- To isolate and characterize RNA from mouse L cell mitochondria, distinguishing it from cytoplasmic RNA.
- To identify and differentiate RNA species from potential DNA contaminants in mitochondrial preparations.
Main Methods:
- Differential centrifugation for purifying rat liver mitochondria.
- Phenol extraction and sucrose density gradient centrifugation for rat liver RNA isolation and analysis.
- Actinomycin D treatment to suppress cytoplasmic rRNA synthesis in mouse L cells.
- Cold and hot phenol-sodium dodecyl sulfate methods for mouse L cell mitochondrial RNA isolation.
- Agarose-acrylamide gel electrophoresis and deoxyribonuclease/ribonuclease sensitivity assays for RNA characterization.
Main Results:
- Rat liver mitochondria yielded RNA sedimenting at 15S and 13S with a specific nucleotide composition.
- Mouse L cell mitochondria, under conditions suppressing cytoplasmic rRNA, yielded RNA components sedimenting at 15S and 12.5S, with distinct electrophoretic mobilities (21S(E) and 12S(E)).
- A 21S component in crude L-cell mitochondrial preparations was identified as DNA due to its nuclease sensitivity and was attributed to nuclear fragment contamination.
Conclusions:
- Mitochondria contain unique RNA species with defined sedimentation properties and nucleotide compositions.
- Distinguishing mitochondrial RNA from cytoplasmic RNA and DNA contaminants is essential for accurate molecular analysis.
- The methods employed successfully isolated and characterized mitochondrial RNA, providing insights into its nature and purity.