TATA box
Encyclopedia
The TATA box is a DNA sequence
(cis-regulatory element
) found in the promoter region of genes in archaea
and eukaryote
s; approximately 24% of human genes contain a TATA box within the core promoter.
Considered to be the core promoter sequence, it is the binding site of either general transcription factor
s or histone
s (the binding of a transcription factor blocks the binding of a histone and vice versa) and is involved in the process of transcription
by RNA polymerase
.
5'-TATAAA-3' or a variant, which is usually followed by three or more adenine
bases. It is usually located 25 base pairs upstream of the transcription site. The sequence is believed to have remained consistent throughout much of the evolution
ary process, possibly originating in an ancient eukaryotic organism
.
It is normally bound by the TATA binding protein
(TBP) in the process of transcription, which unwinds the DNA, and bends it through 80°. The AT-rich sequence facilitates easy unwinding (due to weaker base-stacking interactions among A and T than G and C). The TBP is an unusual protein in that it binds to the minor groove and binds with a β sheet
.
The TATA box is usually found at the binding site of RNA polymerase II
. TFIID, a transcription factor
, binds to the TATA box, followed by TFIIA binding to the upstream part of TFIID. TFIIB can then bind to the downstream part of TFIID. The polymerase can then recognize this multi-protein complex and bind to it, along with various other transcription factors such as TFIIF, TFIIE and TFIIH. Transcription is then initiated, and the polymerase moves along the DNA strand, leaving TFIID and TFIIA bound to the TATA box. These can then facilitate the binding of additional RNA polymerase II molecules.
This cluster of RNA polymerase II and various transcription factors is known as a basal transcriptional complex (BTC). In this state, it only gives a low level of transcription. Other factors must stimulate the BTC to increase transcription levels. One such example of a BTC stimulating region of DNA is the CAAT box
.
Most genes lack a TATA box and use an initiator element or downstream core promoter instead. Nevertheless, TBP is always involved and is forced to bind without sequence specificity. A genome-wide study put the fraction of TATA-dependent human promoters at ~10%. An earlier study of ~1,000 genes found 32% of the promoters had a TATA box.
.
DNA sequence
The sequence or primary structure of a nucleic acid is the composition of atoms that make up the nucleic acid and the chemical bonds that bond those atoms. Because nucleic acids, such as DNA and RNA, are unbranched polymers, this specification is equivalent to specifying the sequence of...
(cis-regulatory element
Cis-regulatory element
A cis-regulatory element or cis-element is a region of DNA or RNA that regulates the expression of genes located on that same molecule of DNA . This term is constructed from the Latin word cis, which means "on the same side as". These cis-regulatory elements are often binding sites for one or...
) found in the promoter region of genes in archaea
Archaea
The Archaea are a group of single-celled microorganisms. A single individual or species from this domain is called an archaeon...
and eukaryote
Eukaryote
A eukaryote is an organism whose cells contain complex structures enclosed within membranes. Eukaryotes may more formally be referred to as the taxon Eukarya or Eukaryota. The defining membrane-bound structure that sets eukaryotic cells apart from prokaryotic cells is the nucleus, or nuclear...
s; approximately 24% of human genes contain a TATA box within the core promoter.
Considered to be the core promoter sequence, it is the binding site of either general transcription factor
Transcription factor
In molecular biology and genetics, a transcription factor is a protein that binds to specific DNA sequences, thereby controlling the flow of genetic information from DNA to mRNA...
s or histone
Histone
In biology, histones are highly alkaline proteins found in eukaryotic cell nuclei that package and order the DNA into structural units called nucleosomes. They are the chief protein components of chromatin, acting as spools around which DNA winds, and play a role in gene regulation...
s (the binding of a transcription factor blocks the binding of a histone and vice versa) and is involved in the process of transcription
Transcription (genetics)
Transcription is the process of creating a complementary RNA copy of a sequence of DNA. Both RNA and DNA are nucleic acids, which use base pairs of nucleotides as a complementary language that can be converted back and forth from DNA to RNA by the action of the correct enzymes...
by RNA polymerase
RNA polymerase
RNA polymerase is an enzyme that produces RNA. In cells, RNAP is needed for constructing RNA chains from DNA genes as templates, a process called transcription. RNA polymerase enzymes are essential to life and are found in all organisms and many viruses...
.
Overview
The TATA box has the core DNA sequenceDNA sequence
The sequence or primary structure of a nucleic acid is the composition of atoms that make up the nucleic acid and the chemical bonds that bond those atoms. Because nucleic acids, such as DNA and RNA, are unbranched polymers, this specification is equivalent to specifying the sequence of...
5'-TATAAA-3' or a variant, which is usually followed by three or more adenine
Adenine
Adenine is a nucleobase with a variety of roles in biochemistry including cellular respiration, in the form of both the energy-rich adenosine triphosphate and the cofactors nicotinamide adenine dinucleotide and flavin adenine dinucleotide , and protein synthesis, as a chemical component of DNA...
bases. It is usually located 25 base pairs upstream of the transcription site. The sequence is believed to have remained consistent throughout much of the evolution
Evolution
Evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organisation, including species, individual organisms and molecules such as DNA and proteins.Life on Earth...
ary process, possibly originating in an ancient eukaryotic organism
Organism
In biology, an organism is any contiguous living system . In at least some form, all organisms are capable of response to stimuli, reproduction, growth and development, and maintenance of homoeostasis as a stable whole.An organism may either be unicellular or, as in the case of humans, comprise...
.
It is normally bound by the TATA binding protein
TATA Binding Protein
The TATA-binding protein is a general transcription factor that binds specifically to a DNA sequence called the TATA box. This DNA sequence is found about 35 base pairs upstream of the transcription start site in some eukaryotic gene promoters...
(TBP) in the process of transcription, which unwinds the DNA, and bends it through 80°. The AT-rich sequence facilitates easy unwinding (due to weaker base-stacking interactions among A and T than G and C). The TBP is an unusual protein in that it binds to the minor groove and binds with a β sheet
Beta sheet
The β sheet is the second form of regular secondary structure in proteins, only somewhat less common than the alpha helix. Beta sheets consist of beta strands connected laterally by at least two or three backbone hydrogen bonds, forming a generally twisted, pleated sheet...
.
The TATA box is usually found at the binding site of RNA polymerase II
RNA polymerase II
RNA polymerase II is an enzyme found in eukaryotic cells. It catalyzes the transcription of DNA to synthesize precursors of mRNA and most snRNA and microRNA. A 550 kDa complex of 12 subunits, RNAP II is the most studied type of RNA polymerase...
. TFIID, a transcription factor
Transcription factor
In molecular biology and genetics, a transcription factor is a protein that binds to specific DNA sequences, thereby controlling the flow of genetic information from DNA to mRNA...
, binds to the TATA box, followed by TFIIA binding to the upstream part of TFIID. TFIIB can then bind to the downstream part of TFIID. The polymerase can then recognize this multi-protein complex and bind to it, along with various other transcription factors such as TFIIF, TFIIE and TFIIH. Transcription is then initiated, and the polymerase moves along the DNA strand, leaving TFIID and TFIIA bound to the TATA box. These can then facilitate the binding of additional RNA polymerase II molecules.
This cluster of RNA polymerase II and various transcription factors is known as a basal transcriptional complex (BTC). In this state, it only gives a low level of transcription. Other factors must stimulate the BTC to increase transcription levels. One such example of a BTC stimulating region of DNA is the CAAT box
CAAT box
In molecular biology, a CCAAT box is a distinct pattern of nucleotides with GGCCAATCT consensus sequence that occur upstream by 75-80 bases to the initial transcription site. The CAAT box signals the binding site for the RNA transcription factor, and is typically accompanied by a conserved...
.
Most genes lack a TATA box and use an initiator element or downstream core promoter instead. Nevertheless, TBP is always involved and is forced to bind without sequence specificity. A genome-wide study put the fraction of TATA-dependent human promoters at ~10%. An earlier study of ~1,000 genes found 32% of the promoters had a TATA box.
Binding of histones
The binding of histones involves the N-terminal tail of Histone H4Histone H4
Histone H4 is one of the 5 main histone proteins involved in the structure of chromatin in eukaryotic cells. Featuring a main globular domain and a long N terminal tail, H4 is a structural component of the nucleosome, and is subject to covalent modification, including acetylation and methylation,...
.