Editing Messenger RNA (section)

====Editing====
In some instances, an mRNA will be [[RNA editing|edited]], changing the nucleotide composition of that mRNA. An example in humans is the [[apolipoprotein B#RNA editing|apolipoprotein B]] mRNA, which is edited in some tissues, but not others. The editing creates an early stop codon, which, upon translation, produces a shorter protein. Another well-defined example is A-to-I (adenosine to inosine) editing, which is carried out by double-strand specific adenosine-to inosine editing (ADAR) enzymes. This can occur in both the open reading frame and untranslated regions, altering the structural properties of the mRNA. Although essential for development, the exact role of this editing is not fully understood <ref>{{cite journal | doi=10.1186/gm508 | doi-access=free | title=Adenosine-to-inosine RNA editing and human disease | date=2013 | journal=Genome Medicine | volume=5 | issue=11 | page=105 | pmid=24289319 | pmc=3979043 | vauthors = Slotkin W, Nishikura K }}</ref>