(Molecular biology) The portion of a messenger RNA molecule which serves as the template for the generation of protein. It is translated into protein by the molecular complex known as the ribosome. The coding region begins with an AUG start codon and ends with a stop codon - either UAA, UAG or UGA.
In most messenger RNA molecules the coding region is flanked at both ends by untranslated regions, which serve regulatory functions but do not code for protein.