Question

Why is actively translated mRNA more stable in the cytoplasm, whereas non actively translated mRNA is rapidly degraded?

Answer 1

Exonucleases and endonucleases are the enzymes which are are present in the cytoplasm. These enzymes are responsible for cutting or digesting nucleic acid, DNA and RNA.

Whenever the messenger RNA or any other type of RNA is present in cytoplasm, then there are high chances that it will be degraded by the action of these nucleases. But messenger RNA is protected from the effect of these enzymes by the presence of a cap and tail at both the ends.

Apart from this, messenger RNA which is undergoing translation actively and the one which is not involved in translation is more protected by the action of these enzymes. This is because when the messenger RNA is undergoing translation, most of the part of messenger RNA is covered by ribosomes. These ribosomes help in the masking of restriction sites of restriction enzyme present on the messenger RNA and therefore restriction enzymes cannot recognise and cut the messenger are in the at the sites.

On the other hand, messenger RNA not undergoing translation is not associated with ribosomes and therefore the restriction sites are exposed easily for the action of restriction enzymes.

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