12: RNA processing
- Page ID
- 382
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RNA processing refers to any covalent modification to the RNA that occurs after transcription. This includes specific cleavage, addition of nucleotides, methylation or other modification of the nucleotides, and removal of introns by splicing.
- 12.2: Modifications at the 5' and 3' ends of mRNA
- As discussed previously, eukaryotic mRNAs are capped at their 5' end and polyadenylated at their 3' end. In vitro assays for these reactions have been developed, and several of the enzymatic activities have been identified. These will be reviewed in this section. Polyadenylation is not limited to eukaryotes. Several mRNAs in E. coli are polyadenylated as well. This is a fairly new area of study.
- 12.4: Self‑splicing by group I introns (pre‑rRNA of Tetrahymena)
- The splicing of the pre-RNA can occur in the absence of any added protein.
- 12.5: RNAs Can Function as Enzymes
- Viroids and virusoids have a self-cleaving activity.
- 12.8: Alternative Splicing
- For many genes, all the introns in the mRNA are spliced out in a unique manner, resulting in one mRNA per gene. But there is a growing number of examples of other genes in which certain exons are included or excluded from the final mature mRNA, a process called alternative splicing
- 12.9: RNA editing
- RNA editing refers to changing the sequence of RNA after transcription, either by adding nucleotides, taking them away, or substituting one for another.