 This means that the segment following the promoter is variable depending on the desired product – it could be a sequence determining the amino acids for insulin, for hepatitis B vaccine or for interferon.The expression cassette is terminated by a following terminator sequence that provides a proper stop of the transcription.The promoter elements of the "O. polymorpha" system are derived from genes that are highly expressed, from instance from the MOX gene, the "FMD" gene or the "TPS1" gene mentioned before.