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[Stabilization of polyribosomal mRNA in rat liver cells under protein synthesis inhibition by cycloheximide]
Abstract:
It was found that in the course of centrifugation of the postmitochondrial fraction from rat liver in the sucrose concentration gradient, mRNA located in the EDTA-resistant structures sedimented together with polyribosomes. The same structures were detected in the polyribosomal fraction of liver cells after injection of ethionine to the animals. Centrifugation of polyribosomes through a layer of 2.0 M sucrose at 105 000 g for 4 hrs and subsequent centrifugation through a layer of 1.0 M sucrose resulted in the disappearance of the complexes from the polyribosomal fraction. Evidence for the absence of destruction of labelled polyribosomal mRNA in liver cells following the injection of cycloheximide were obtained. Actinomycin D also stabilized polyribosomal mRNA in liver cells, however, in a much lesser degree as compared to cycloheximide. Possible mechanisms of the stabilizing effects of cycloheximide and actinomycin D on polyribosomal mRNA in liver cells are discussed.
Insights
EDTA-resistant structures containing messenger RNA (mRNA) were found to sediment with polyribosomes in rat liver cells. Cycloheximide and Actinomycin D were observed to stabilize this polyribosomal mRNA.
Area of Science:
- Molecular Biology
- Cell Biology
- Biochemistry
Context:
- Investigates the localization and stability of messenger RNA (mRNA) within cellular structures.
- Focuses on polyribosomes and associated complexes in rat liver cells.
- Examines the effects of ethionine, cycloheximide, and Actinomycin D on mRNA dynamics.
Purpose:
- To identify and characterize EDTA-resistant structures containing mRNA that co-sediment with polyribosomes.
- To investigate the stability of polyribosomal mRNA under different experimental conditions, including drug treatments.
- To explore the potential mechanisms behind the stabilizing effects of cycloheximide and Actinomycin D on mRNA.
Summary:
- Messenger RNA (mRNA) in EDTA-resistant structures was found to sediment with polyribosomes in rat liver cell fractions.
- These mRNA-containing structures were also detected after ethionine injection and disappeared upon specific sucrose gradient centrifugation.
- Cycloheximide demonstrated a significant stabilizing effect on polyribosomal mRNA, while Actinomycin D showed a lesser degree of stabilization.
Impact:
- Provides insights into the compartmentalization and regulation of mRNA in eukaryotic cells.
- Highlights the role of specific cellular structures in mRNA localization and stability.
- Contributes to understanding the mechanisms of mRNA regulation by drugs like cycloheximide and Actinomycin D.