Transcription of a bacterial gene by RNA polymerase. (A) Production of an RNA molecule in bacteria. (B)
The nucleotide sequences that signal to a bacterial RNA polymerase where to begin transcribing and where to stop. The green-shaded regions in the top diagram in (B) represent the DNA sequences that are required to create a promoter. The numbers represent the positions of nucleotides counting from the first nucleotide transcribed, which is designated +1. The red-shaded regions in the bottom diagram in (B) represent sequences that signal to RNA polymerase to terminate transcription