Summary
A DNA sequence where RNA polymerase and transcription factors bind to start transcription of a gene.
In depth
In bacteria, the -10 (Pribnow) and -35 boxes bind sigma factor; in eukaryotes the TATA box around -25 binds TBP, part of TFIID, and recruits general transcription factors and Pol II. Promoter strength affects expression level.
Mutations in a promoter can reduce or raise gene expression.
Promoter strength determines expression level: strong ones have sequences close to the consensus. Eukaryotic promoters often lack a TATA box, especially in housekeeping genes with CpG islands, and use other elements such as the initiator and downstream promoter element. The core promoter spans about 100 base pairs, while regulatory elements extend further.
Synthetic biology builds libraries of promoters of different strengths to tune circuits. Inducible promoters such as the lac or tetracycline-responsive ones switch expression on by adding a chemical, used in research and in protein production.
Remember: the promoter is not transcribed; it is the landing site that points RNA polymerase in a direction.
Frequently asked questions
What is Promoter?
A DNA sequence where RNA polymerase and transcription factors bind to start transcription of a gene.
Which area of biology covers Promoter, and how advanced is it?
Promoter is one of the 52 topics in Molecular Biology. It is rated Intermediate, so it suits learners who already know the core vocabulary. Related topics in this area include Transcription, RNA Polymerase, Start and Stop Codons.
Can you give an example of Promoter?
In synthetic biology, different promoters are used to tune how much protein is made.
What should I learn before Promoter?
Work through the Beginner topics in Molecular Biology first, such as Central Dogma, DNA Replication, Base Pairing, then return to Promoter. Intermediate topics assume the Beginner vocabulary.
What topics are related to Promoter?
The closest topics to Promoter are Transcription, RNA Polymerase, Start and Stop Codons, Operon. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand Promoter?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Promoter. To practise the whole of Molecular Biology, use the Molecular Biology quiz.
How is Promoter different from Transcription?
Promoter: A DNA sequence where RNA polymerase and transcription factors bind to start transcription of a gene. Transcription: The process of making an RNA copy of a gene using DNA as a template. Read both side by side and note what each one explains.
How should I study Promoter step by step?
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Transcription and explain the difference aloud. Finally, take the Molecular Biology quiz and come back to this page for any question you miss.