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Characterization of translational-control ribonucleic acid isolated from embryonic chick muscle
Abstract:
Myosin heavy chain (MHC) mRNP particles have been purified from 13-day chick embryonic skeletal muscle by a combination of sucrose density gradient centrifugation and metrizamide buoyant density centrifugation. Associated with the mRNPs are at least three distinct low molecular weight RNA molecules including translational-control RNA (tcRNA). This particular RNA contains 102 nucleotides and is uridine and guanine rich, and its nucleotide sequence has been determined. tcRNA102 is capable of inhibiting the translation of the mRNAs with which it is associated upon preincubation in stoichiometric amounts. Under these conditions, endogenous reticulocyte mRNA is not inhibited. Under appropriate salt and temperature conditions, tcRNA102 is capable of reassociating with myosin heavy chain (MHC) mRNA, thus altering the sedimentation characteristics of the mRNA. This suggests that the mRNA-tcRNA102 interactions alter the secondary structure of the mRNA. In addition, tcRNA102 does not associate with ribosomal RNA or globin mRNA, suggesting that some degree of specificity is involved with the RNA-RNA interactions.
Insights
A novel 102-nucleotide translational-control RNA (tcRNA102) inhibits myosin heavy chain (MHC) mRNA translation. This RNA specifically reassociates with MHC mRNA, altering its structure and function.
Area of Science:
- Molecular Biology
- RNA Biology
- Protein Synthesis
Background:
- Myosin heavy chain (MHC) messenger ribonucleoprotein particles (mRNPs) are crucial for muscle development.
- Understanding the regulation of MHC mRNA translation is key to muscle gene expression.
Purpose of the Study:
- To identify and characterize regulatory RNA molecules associated with MHC mRNPs.
- To investigate the function and specificity of translational-control RNA (tcRNA).
Main Methods:
- Purification of MHC mRNP particles from chick embryonic skeletal muscle.
- Sucrose density gradient and metrizamide buoyant density centrifugation.
- RNA sequencing and nucleotide sequence determination of tcRNA102.
- In vitro translation inhibition assays.
- RNA-RNA reassociation studies.
Main Results:
- Isolation of MHC mRNPs containing at least three low molecular weight RNAs, including tcRNA.
- Determination of the 102-nucleotide sequence of tcRNA (tcRNA102), rich in uridine and guanine.
- tcRNA102 demonstrated stoichiometric inhibition of MHC mRNA translation.
- tcRNA102 specifically reassociated with MHC mRNA, altering its sedimentation, suggesting structural changes.
- tcRNA102 did not associate with globin mRNA or ribosomal RNA, indicating specific RNA-RNA interactions.
Conclusions:
- A novel RNA molecule, tcRNA102, regulates MHC mRNA translation.
- tcRNA102-MHC mRNA interactions are specific and alter mRNA secondary structure.
- This discovery provides insights into post-transcriptional gene regulation in muscle development.