IUPAC definition : The DNA region, usually upsteam to the coding sequence of a gene or operon, which
binds and directs RNA polymerase to the correct transcriptional start site and thus
permits the initation of transcription.;
The DNA region, usually upsteam to the coding sequence of a gene or operon, which
binds and directs RNA polymerase to the correct transcriptional start site and thus
permits the initation of transcription.