The promoter region
The promoter region is the section of DNA that indicates where a gene begins. This region initiates transcription.
Enzymes that initiate transcription of mRNA bind to promoter regions.
In prokaryotes, there is a promoter structure known as the TATAAT box. Its name reflects the base sequence.
The TATAAT box is positioned about 10 bases in front of the first base of the gene (upstream of the gene) and is essential for transcription.
About 35 bases upstream of the gene, there is another promoter region with the sequence TTGACA. This sequence alters the rate of transcription (the number of mRNA molecules transcribed in a given time)
Eukaryotic promoters are more diverse and less regular than prokaryotic promoters. There are some common promoters, like the TATA box (sequence TATAAA).