Open reading frame

An open reading frame (ORF) is a DNA or RNA substring that could be translated into a protein string. It begins with a start codon and ends with a stop codon, with no stop codons appearing in between.

The presence of an ORF is necessary to consider this substring as possibly deriving from the coding region of a gene. In order to guarantee transcription and translation, the reading frame must contain a number of additional regulatory elements, such as a promoter region to initiate translation.