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Rapid mRNA degradation via AU-rich elements is a critical mechanism for preventing the overproduction of potent cytokines such as tumor necrosis factor (TNF) and granulocyte-macrophage colony stimulating factor (GM-CSF). [40] AU-rich elements also regulate the biosynthesis of proto-oncogenic transcription factors like c-Jun and c-Fos. [41]
Prokaryotic mRNA degradation poses a difficulty to researchers developing mRNA vaccines. This is the case because the degradation means that mRNA is not stable, and might not deliver the vaccine effectively; [ 8 ] this problem has been combated by chemically modifying mRNA, using several different kinds of chemicals, such as lipids , lipid-like ...
Non-stop decay (NSD) is a cellular mechanism of mRNA surveillance to detect mRNA molecules lacking a stop codon and prevent these mRNAs from translation. The non-stop decay pathway releases ribosomes that have reached the far 3' end of an mRNA and guides the mRNA to the exosome complex, or to RNase R in bacteria for selective degradation.
The poly(A) tail is important for the nuclear export, translation and stability of mRNA. The tail is shortened over time, and, when it is short enough, the mRNA is enzymatically degraded. [2] However, in a few cell types, mRNAs with short poly(A) tails are stored for later activation by re-polyadenylation in the cytosol. [3]
The RNA's destruction process is very complicated. To make it easier to understand, we use as an example the mRNA degradation procedure in Escherichia coli because it is the best known process. It is mediated mainly by endo- and ribo- nucleases. The enzymes RNase II and PNPase (polynucleotide phosphorylase) degrade mRNA in a 3'→5' way.
Inside cells, there is a balance between the processes of translation and mRNA decay. [2] Messages which are being actively translated are bound by polysomes and the eukaryotic initiation factors eIF-4E and eIF-4G (in eukaryotes). This blocks access to the cap by the decapping enzyme DCP2 and protects the mRNA molecule. In nutrient-starvation ...
First, degradation of the mRNA by 5′ exonucleases is prevented (as mentioned above) by functionally looking like a 3′ end. Second, the CBC and eIF4E/eIF4G block the access of decapping enzymes to the cap. This increases the half-life of the mRNA, essential in eukaryotes as the export and translation processes take significant time.
P-bodies were originally proposed to be the sites of mRNA degradation in the cell and involved in decapping and digestion of mRNAs earmarked for destruction. [6] [7] Later work called this into question suggesting P bodies store mRNA until needed for translation. [8] [5] [9] In neurons, P-bodies are moved by motor proteins in response to ...