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Possible involvement of messenger RNA-associated proteins in protein synthesis
Abstract:
Two distinct forms of globin messenger RNA were isolated from mouse spleen cells infected with Friend erythroleukemia virus: polyribosomal messenger ribonucleoprotein particles (15S mRNP), and their corresponding protein-free mRNAs obtained by chemical deproteinization. The translation efficiencies of both messenger forms were assayed in a Krebs II ascites cell-free system. Selective removal of RNA-binding proteins from the ascites cell lysate did not affect globin synthesis when the mRNA was supplied as 15S mRNP; deproteinized mRNA however was not translated. Only in the presence of two fractions of RNA-binding proteins was the protein-free mRNA translated. Some of the RNA-binding proteins have the same molecular weights and isoelectric points as the principal proteins of 15S mRNP.
Insights
RNA-binding proteins are essential for translating globin messenger RNA (mRNA) in Friend erythroleukemia virus-infected cells. Protein-free mRNA requires specific protein fractions for translation, highlighting the role of these proteins in gene expression.
Area of Science:
- Molecular Biology
- Virology
- Cell Biology
Background:
- Friend erythroleukemia virus (FEV) induces globin expression in mouse spleen cells.
- Messenger RNA (mRNA) exists in cells associated with proteins as messenger ribonucleoprotein particles (mRNPs).
- The role of RNA-binding proteins in mRNA translation efficiency is not fully understood.
Purpose of the Study:
- To investigate the translational efficiency of different forms of globin mRNA.
- To determine the necessity of RNA-binding proteins for globin mRNA translation.
- To identify proteins associated with globin mRNA.
Main Methods:
- Isolation of 15S mRNP and protein-free globin mRNA from FEV-infected mouse spleen cells.
- Assay of translation efficiency in a Krebs II ascites cell-free system.
- Chemical deproteinization of mRNA and fractionation of RNA-binding proteins.
Main Results:
- 15S mRNP was efficiently translated in the cell-free system.
- Protein-free globin mRNA was not translated unless specific RNA-binding protein fractions were added.
- Some isolated RNA-binding proteins shared molecular characteristics with proteins found in 15S mRNP.
Conclusions:
- RNA-binding proteins are crucial for the translation of globin mRNA.
- The protein-free mRNA requires specific protein factors for efficient translation.
- These findings suggest a regulatory role for RNA-binding proteins in globin gene expression.