The TATA box is a conserved DNA sequence found in the core promoter region of many eukaryoticgenes, typically located about 25–35 base pairs upstream of the transcription start site (TSS). It serves as a binding site for the TATA-binding protein (TBP), which is a subunit of the transcription factor TFIID. This interaction is crucial for the initiation of transcription by RNA polymerase II.
Consensus Sequence:
Commonly written as: TATAAA (though variations exist)
It is AT-rich, which makes the DNA easier to unwind due to fewer hydrogen bonds compared to GC pairs.
Function:
Function
Description
Transcription initiation
Helps position RNA polymerase II correctly at the promoter
Binding site for TBP
TBP binding bends DNA and recruits additional transcription factors
Promoter recognition
Found in many genes with tightly regulated or high levels of expression
Role in Transcription (Simplified):
TBP binds to the TATA box.
This recruits TFIID, which helps assemble the pre-initiation complex (PIC).
Other general transcription factors (e.g., TFIIA, TFIIB, TFIIE, TFIIF, TFIIH) are recruited.
RNA polymerase II is positioned correctly to begin transcribing mRNA from the DNA template.
Location and Presence:
Property
Description
Location
~25–35 bp upstream of TSS
Found in
Core promoters of many but not all genes
More common in
Highly expressed or developmentally regulated genes
Absent in
Some housekeeping genes, which use other core promoter elements (e.g., Inr, DPE)
Comparison to Other Promoter Elements:
Element
Location
Role
TATA box
~ -25 bp
TBP binding, initiates transcription complex
Initiator (Inr)
Around +1 (TSS)
Can direct transcription start without TATA
BRE (TFIIB recognition element)
Upstream or downstream of TATA
Helps TFIIB binding
DPE (Downstream promoter element)
~+30 bp
Works with Inr in TATA-less promoters
Clinical Relevance:
Mutations in the TATA box can disrupt transcription and lead to disease (e.g., β-thalassemia due to reduced globin gene transcription).
