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[The major cytoplasmic mRNP protein, p50, is required for efficient mRNA translation in vitro]
Abstract:
The major cytoplasmic mRNP protein of somatic cells, p50, is the member of the Y-box-binding transcription factor family and can control gene expression at two levels including mRNA transcription and translation. It has been demonstrated that p50 is responsible for the inactive state of mRNA within free mRNPs. In this work, we show that the Y-box-containing DNA (Y-DNA) predominantly binds to p50 in rabbit reticulocyte lysates and causes translation inhibition of the endogenous and exogenous globin mRNA and prokaryotic beta-galactosidase mRNA. Preincubation of Y-DNA with purified p50 prevents the inhibition. Inhibition of protein biosynthesis by the Y-DNA is not due to the degradation or functional inactivation of mRNA. The inhibition is associated with the decay of polyribosomes and dissociation of a newly synthesized protein from the ribosomes. The data indicate that Y-DNA inhibits protein biosynthesis predominantly at the initiation stage and that p50 is an essential component of the translation initiation apparatus.
Insights
Y-box-containing DNA (Y-DNA) inhibits protein synthesis by binding to p50, a key protein in translation. This interaction prevents the initiation of protein biosynthesis, highlighting p50
Area of Science:
- Molecular Biology
- Gene Expression Regulation
Context:
- The protein p50, a Y-box-binding transcription factor, regulates gene expression at transcriptional and translational levels.
- p50 is known to maintain mRNA in an inactive state within messenger ribonucleoprotein complexes (mRNPs).
Purpose:
- To investigate the mechanism by which Y-box-containing DNA (Y-DNA) inhibits protein biosynthesis.
- To determine the role of p50 in Y-DNA-mediated translation inhibition.
Summary:
- Y-box-containing DNA (Y-DNA) was found to bind to p50 in rabbit reticulocyte lysates, inhibiting the translation of globin and beta-galactosidase mRNAs.
- This inhibition occurs at the initiation stage of protein synthesis, evidenced by polyribosome decay and dissociation of nascent proteins.
- Pre-incubation with purified p50 blocked Y-DNA-induced inhibition, confirming p50's essential role.
Impact:
- Identifies Y-DNA as a specific inhibitor of protein translation initiation.
- Establishes p50 as a critical component of the translation initiation machinery.
- Provides insights into post-transcriptional gene regulation mechanisms involving Y-box binding proteins.