Related Experiment Video

Updated: Aug 5, 2026

Cell-Free Production of Proteoliposomes for Functional Analysis and Antibody Development Targeting Membrane Proteins
08:46

Cell-Free Production of Proteoliposomes for Functional Analysis and Antibody Development Targeting Membrane Proteins

Published on: September 22, 2020

In vitro synthesis of A-particle structual protein by membrane-bound polyribosomes

K K Lueders

    Journal of Virology
    |June 1, 1976
    PubMed

    Insights

    Mouse myeloma cells synthesize A-particle proteins on membrane-bound polyribosomes, not free ones. This study identifies the specific cellular location for A-particle protein synthesis in vitro.

    Area of Science:

    • Molecular Biology
    • Cell Biology
    • Biochemistry

    Background:

    • Polyribosomes are complexes of messenger RNA and ribosomes involved in protein synthesis.
    • Myeloma cells, like MOPC-104E, are known for producing specific proteins.

    Purpose of the Study:

    • To investigate the site of A-particle protein synthesis within mouse myeloma cells.
    • To differentiate the protein synthesis capabilities of membrane-bound versus free polyribosomes.

    Main Methods:

    • Isolation and separation of membrane-bound and free polyribosomes from MOPC-104E mouse myeloma cells.
    • In vitro protein synthesis assay using [35S]methionine incorporation.
    • Radioimmunological assay and peptide mapping to identify synthesized proteins.

    Main Results:

    • Membrane-bound polyribosomes incorporated [35S]methionine into A-particle proteins in vitro.
    • Free polyribosomes did not show significant incorporation of [35S]methionine into A-particle proteins.
    • Peptide mapping confirmed the in vitro synthesized product was indeed A-particle protein.

    Conclusions:

    • A-particle protein synthesis in MOPC-104E mouse myeloma cells occurs on membrane-bound polyribosomes.
    • This finding localizes the synthesis of specific viral-associated proteins to the endoplasmic reticulum-associated translational machinery.

    More Related Videos

    Cell-Free Protein Synthesis System for Building Synthetic Cells07:43

    Cell-Free Protein Synthesis System for Building Synthetic Cells

    Published on: April 19, 2024

    In Vitro Reassociation Assay to Measure the Formation of 80S Ribosomal Particles Using Salt-washed Ribosomal Subunits06:09

    In Vitro Reassociation Assay to Measure the Formation of 80S Ribosomal Particles Using Salt-washed Ribosomal Subunits

    Published on: December 16, 2025

    Related Concept Videos

    Ribosomes01:27

    Ribosomes

    Ribosomes translate genetic information encoded by messenger RNA (mRNA) into proteins. Both prokaryotic and eukaryotic cells have ribosomes. Cells that synthesize large quantities of protein—such as secretory cells in the human pancreas—can contain millions of ribosomes.Ribosome Structure and AssemblyRibosomes are composed of ribosomal RNA (rRNA) and proteins. In eukaryotes, rRNA is transcribed from genes in the nucleolus—a part of the nucleus that specializes in ribosome production. Within the...
    Ribosomal RNA Synthesis02:53

    Ribosomal RNA Synthesis

    Ribosome synthesis is a highly complex and coordinated process involving more than 200 assembly factors. The synthesis and processing of ribosomal components occurs not only in the nucleolus but also in the nucleoplasm and the cytoplasm of eukaryotic cells.
    Ribosome biogenesis begins with the synthesis of 5S and 45S pre-rRNAs by distinct RNA polymerases. The primary transcripts are extensively processed and modified before they are bound and folded by ribosomal proteins and assembly factors,...
    Directing Proteins to the Rough Endoplasmic Reticulum01:34

    Directing Proteins to the Rough Endoplasmic Reticulum

    The organelle-specific signaling sequences direct proteins synthesized in the cytosol to their final destination like ER, mitochondria, peroxisomes, etc. Some of the proteins directed to ER are then trafficked via vesicles to other organelles within the cell or the extracellular environment through the Golgi complex. For example, the rough ER synthesizes soluble proteins for transportation to the lysosomes or secretion out of the cell. It can also synthesize transmembrane proteins that can...
    Cotranslational Protein Translocation01:20

    Cotranslational Protein Translocation

    Translocation of proteins across membranes is an ancient process that occurs even in bacteria and archaebacteria. In fact, the components of the translocation machinery are still conserved between prokaryotes and eukaryotes.
    Sec61 channel partners for cotranslational translocation
    During cotranslational translocation, the Sec61 channel partners with the signal recognition particle (SRP), the signal recognition particle receptor (SR), and the ribosomes to transport the nascent polypeptide chain...
    Post-translational Translocation of Proteins to the RER01:27

    Post-translational Translocation of Proteins to the RER

    A sizable fraction of proteins destined for ER are first synthesized in the cell cytosol and then transported across the ER membrane–a process called post-translational translocation. Similar to cotranslationally translocated proteins, these proteins also use the Sec translocon complex to enter the ER lumen.
    Targeting proteins to the ER
    Hsp40 and Hsp70 chaperone molecules bind the translated proteins in the cytosol to prevent their folding. The chaperone binding helps to keep the signal...
    Ribosomes01:27

    Ribosomes

    Ribosomes translate genetic information encoded by messenger RNA (mRNA) into proteins. Both prokaryotic and eukaryotic cells have ribosomes. Cells that synthesize large quantities of protein—such as secretory cells in the human pancreas—can contain millions of ribosomes.
    Ribosome Structure and Assembly
    Ribosomes are composed of ribosomal RNA (rRNA) and proteins. In eukaryotes, rRNA is transcribed from genes in the nucleolus—a part of the nucleus that specializes in ribosome production. Within...