Editing Messenger RNA (section)

===Nonsense-mediated decay===
{{main|Nonsense-mediated decay}}

Eukaryotic messages are subject to surveillance by [[nonsense-mediated decay]] (NMD), which checks for the presence of premature stop codons (nonsense codons) in the message. These can arise via incomplete splicing, [[V(D)J recombination]] in the [[adaptive immune system]], mutations in DNA, transcription errors, [[leaky scanning]] by the ribosome causing a [[frame shift]], and other causes. Detection of a premature stop codon triggers mRNA degradation by 5' decapping, 3' [[poly(A)]] tail removal, or [[endonuclease|endonucleolytic cleavage]].<ref name=Isken2007>{{cite journal | vauthors = Isken O, Maquat LE | title = Quality control of eukaryotic mRNA: safeguarding cells from abnormal mRNA function | journal = Genes & Development | volume = 21 | issue = 15 | pages = 1833–1856 | date = August 2007 | pmid = 17671086 | doi = 10.1101/gad.1566807 | doi-access = free }}</ref>