E. coli promoters

Transcriptional Promoters

    A promoter is a short DNA sequence that signals the RNAPol where to begin transcription. Comparison of many E. coli DNA gene sequences shows two common promoter motifs [yellow boxes] with similar sequences, which are located approximately -10 [the TATA Box] & -35  [the CAT Box] bases 5' ('upstream') from the start point of RNA transcription [blue box]. Similar promoter regions occur in other prokaryotic and eukaryotic genes.

    It is important to remember
that the promoter is a DNA signal  for the downstream start point of transcription at position +1. The start point of translation is recognizable in the DNA still further downstream, but is actually on the transcribed RNA molecule, at the AUG start codon of the gene. The start codon does not appear in the diagram.


Figure © 2004 by Griffiths et al. ; text © 2024 by Steven M. Carr