RNA processing

[biostud]

RNA processing

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Post by biostud » Fri Jun 25, 2010 8:40 pm

We know that 5' capping and 3' polyadenylation are necessary for the mRNA in eucaryotes. These transformations do not happen in procaryotes. Which is the advantage in eucaryotes, excenp from the fact that the RNA is more protected from exonucleases?

[plasmodesmata11]

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Post by plasmodesmata11 » Fri Jun 25, 2010 10:34 pm

Capping may increase the half life. Bacterial mRNA has a half life of around 2 minutes most of the time. When capped, though it is necessary to link to the ribosomes, eukaryotic mRNA has a much longer half life (10-24 hours). It is unsure if the cap is the reason, but my textbook pitches the idea. Not sure about the chemistrybehind it though (not my strongpoint).

[JackBean]

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Post by JackBean » Tue Jul 06, 2010 4:55 pm

more than protection it serves as signal that mRNA is intact, because the cap and polyA are in close proximity

[kolean]

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Post by kolean » Wed Jul 07, 2010 5:34 pm

I don't know if it is an advantage, but the separation of the nucleus and the cytoplasm is why the mRNA needs to be modified for transportation, and then to be 'read' once in the cytoplasm, in a eukaryotic cell. While in the prokaryotic cell, there is no separation, and can actually be 'read' while the mRNA is even still being made.