RNA viruses make proteins by hijacking the host cell's protein synthesis machinery to translate the viral mRNA into viral proteins. These proteins are crucial for the virus to replicate and spread.
Here's a breakdown of the process:
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Viral mRNA Entry: After the RNA virus infects a host cell, its RNA genome (which often functions directly as mRNA) is released into the cytoplasm.
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Ribosome Binding and Translation: The viral mRNA then binds to ribosomes, the protein synthesis factories of the host cell. These ribosomes read the viral mRNA sequence.
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Protein Synthesis: As the ribosome moves along the mRNA, it translates the genetic code into a chain of amino acids, forming a polypeptide. This polypeptide folds into a functional viral protein.
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Location of Translation: Different viral mRNAs might be translated on either free ribosomes in the cytoplasm or ribosomes bound to the endoplasmic reticulum (ER), depending on the function and destination of the resulting protein. For example, proteins destined for the viral envelope are often translated on membrane-bound ribosomes.
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Example: In some RNA viruses, like those mentioned in the reference, specific mRNAs (N-, P-, M-, and L-mRNA) are translated on free ribosomes, while others (G-mRNA) are translated on membrane-bound ribosomes.
In Summary:
RNA viruses exploit the host cell's ribosomes, transfer RNA (tRNA), and other factors necessary for protein synthesis to produce viral proteins based on the instructions encoded in their viral mRNA.
