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[Characteristics of skeletal muscle tissue ribosomes]
Abstract:
Electron-microscopic and chemical analysis of the fraction of RNP-particles, samples of the muscle tissue of the posterior limb of rat and of the human musculus rectus abdominis was carried out for the purpose of characterizing ribosomes of the skeletomuscular tissue. RNP-particle fraction proved to contain functionally-active mono- and poly ribosomes. Two RNA fractions-- RNA1 and RAN11 were isolated. RNA1 proved to represent a set of ribosomic RNA with sedimentation coefficients 26-28S, 16-18S and 4-5S. RNA11 contained no ribosomal RNA, and by its nucleotide composition was affiliated to the nucleotide compostion of rat DNA. The structural organization of ribosomes in the cytoplasm of the muscular fibers corresponded to the pictures observed in the RNP-particle fraction. Polyribosomes are determined in the regions of physiological regeneration of myofibrillae and represent complexes consisting of 5 and more monoribosomes arranged in the form of beads. Ribosomes-like particles proved to escape through the nuclear menbrane; this fact, along with the data of chemical analysis pointed to the periodic passage of RNA from the nucleus into the cytoplasm of hte muscle fiber.
Insights
Skeletomuscular tissue contains functional ribosomes and RNA, with evidence suggesting RNA
Area of Science:
- Molecular Biology
- Cell Biology
Context:
- Ribosomes are crucial for protein synthesis in all cells.
- Skeletomuscular tissue presents unique challenges for ribosome characterization due to its complex structure.
Purpose:
- To characterize ribosomes and their associated RNA (ribonucleic acid) in mammalian skeletal muscle tissue.
- To investigate the structural organization and functional activity of ribosomes in muscle fibers.
Summary:
- Electron microscopy and chemical analysis of RNP-particle fractions from rat and human skeletal muscle identified functional mono- and polyribosomes.
- Two RNA fractions were isolated: RNA1 (ribosomal RNA) and RNA11 (non-ribosomal, similar to rat DNA).
- Polyribosomes were observed in areas of myofibrillar regeneration, and ribosome-like particles were seen exiting the nuclear membrane, indicating nuclear-cytoplasmic RNA transport.
Impact:
- Provides insights into the molecular machinery of protein synthesis in skeletal muscle.
- Suggests a dynamic role for RNA transport from the nucleus to the cytoplasm in muscle cells.
- Contributes to understanding cellular processes underlying muscle function and regeneration.