RNA transcription error

[161927]

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Why doesn't RNA polymerase transcribe mRNA sequence with high fidelity, like DNA polymerase for replication of DNA? Why doesn't the RNA need to be as accurate? If RNA is used for the translation of protein, it seems like it would be important to produce an accurate transcript. How does the cell get away with making transcription errors at a comparatively high rate?

 

[not respect]

It's because if you have one defective protein then oh well, but one defective DNA is heritable/ really bad etc. RNA polymerase can go a lot faster because it doesnt have the proofreading exonuclease activity.

 

[cornpops21]

It's because if you have one defective protein then oh well, but one defective DNA is heritable/ really bad etc. RNA polymerase can go a lot faster because it doesnt have the proofreading exonuclease activity.

Exactly. RNA has a VERY short half-life especially in prokaryotes (only a few seconds). This is because there are so many "bad" things like nucleases in the cytosol that want to tear it apart. This is why we have RNA processing. The whole point of the 5' capping and 3' polyadenylation is to give eukaryotic RNA a long enough half-life for it to be translated into protein.

You don't need proofreading in RNA polymerase b/c if it messes up, the cell still has all the necessary components to start over and make new nucleotide phosphates to get the end protein desired. About 95% of transcribed RNA never even makes it out of the nucleus because of various RNases present. So the cell just recycles that material and uses it again.