A polynucleotide region between promoter and structural gene, necessary for the correct transcription of DNA into mRNA.
An N-terminal extension of polypeptides (also known as the signal sequence) which is necessary for the transport of the protein into or through the membrane or for its secretion into the extracellular medium.
Source: PAC, 1992, 64, 143. 'Glossary for chemists of terms used in biotechnology (IUPAC Recommendations 1992)' on page 158 (https://doi.org/10.1351/pac199264010143)