Editing Messenger RNA (section)

=== Coding regions ===
{{main|Coding region}}
Coding regions are composed of [[codons]], which are decoded and translated into proteins by the ribosome; in eukaryotes usually into one and in prokaryotes usually into several. Coding regions begin with the [[start codon]] and end with a [[stop codon]]. In general, the start codon is an AUG triplet and the stop codon is UAG ("amber"), UAA ("ochre"), or UGA ("opal"). The coding regions tend to be stabilised by internal base pairs; this impedes degradation.<ref>{{cite journal | vauthors = Shabalina SA, Ogurtsov AY, Spiridonov NA | title = A periodic pattern of mRNA secondary structure created by the genetic code | journal = Nucleic Acids Research | volume = 34 | issue = 8 | pages = 2428–2437 | year = 2006 | pmid = 16682450 | pmc = 1458515 | doi = 10.1093/nar/gkl287 }}</ref><ref>{{cite journal | vauthors = Katz L, Burge CB | title = Widespread selection for local RNA secondary structure in coding regions of bacterial genes | journal = Genome Research | volume = 13 | issue = 9 | pages = 2042–2051 | date = September 2003 | pmid = 12952875 | pmc = 403678 | doi = 10.1101/gr.1257503 }}</ref> In addition to being protein-coding, portions of coding regions may serve as regulatory sequences in the [[pre-mRNA]] as [[exonic splicing enhancer]]s or [[exonic splicing silencer]]s.