Transcription factor II D (TF
IID) is one of several
general transcription factors that make up the
RNA polymerase II
RNA polymerase II (RNAP II and Pol II) is a Protein complex, multiprotein complex that Transcription (biology), transcribes DNA into precursors of messenger RNA (mRNA) and most small nuclear RNA (snRNA) and microRNA. It is one of the three RNA pol ...
preinitiation complex.
RNA polymerase II holoenzyme is a form of
eukaryotic
The eukaryotes ( ) constitute the Domain (biology), domain of Eukaryota or Eukarya, organisms whose Cell (biology), cells have a membrane-bound cell nucleus, nucleus. All animals, plants, Fungus, fungi, seaweeds, and many unicellular organisms ...
RNA polymerase II
RNA polymerase II (RNAP II and Pol II) is a Protein complex, multiprotein complex that Transcription (biology), transcribes DNA into precursors of messenger RNA (mRNA) and most small nuclear RNA (snRNA) and microRNA. It is one of the three RNA pol ...
that is recruited to the promoters of
protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...
-coding genes in living cells. It consists of
RNA polymerase II
RNA polymerase II (RNAP II and Pol II) is a Protein complex, multiprotein complex that Transcription (biology), transcribes DNA into precursors of messenger RNA (mRNA) and most small nuclear RNA (snRNA) and microRNA. It is one of the three RNA pol ...
, a subset of general
transcription factor
In molecular biology, a transcription factor (TF) (or sequence-specific DNA-binding factor) is a protein that controls the rate of transcription (genetics), transcription of genetics, genetic information from DNA to messenger RNA, by binding t ...
s, and
regulatory proteins known as SRB proteins. Before the start of
transcription, the transcription Factor II D (TF
IID) complex binds to the
core promoter DNA of the gene through specific recognition of promoter sequence motifs, including the
TATA box,
Initiator,
Downstream Promoter, Motif Ten, or Downstream Regulatory elements.
Functions
* Coordinates the activities of more than 70 polypeptides required for initiation of transcription by RNA polymerase II
* Binds to the core promoter to position the polymerase properly
* Serves as the scaffold for assembly of the remainder of the transcription complex
* Acts as a channel for regulatory signals
Structure
TF
IID is itself composed of TBP and several
subunits called
TATA-binding protein Associated Factors (TBP-associated factors, or TAFs). In a test tube, only TBP is necessary for
transcription at
promoters that contain a
TATA box.
TAFs, however, add promoter selectivity, especially if there is no TATA box sequence for TBP to bind to.
TAFs are included in two distinct complexes, TF
IID
and B-TF
IID.
The TF
IID complex is composed of TBP and more than eight TAFs. But, the majority of TBP is present in the B-TF
IID complex, which is composed of TBP and TAFII170 (
BTAF1
TATA-binding protein-associated factor 172 is a protein that in humans is encoded by the ''BTAF1'' gene.
Function
Initiation of transcription by RNA polymerase II requires the assistance of TATA box-binding protein (TBP; MIM 600075) and TBP-as ...
) in a 1:1 ratio.
TF
IID and B-TF
IID are not equivalent, since transcription reactions utilizing TF
IID are responsive to gene specific transcription factors such as SP1, while reactions reconstituted with B-TF
IID are not.
Subunits in the TF
IID complex include:
[
* TBP (TATA binding protein), or:
** TBP-related factors in animals ( TBPL1; TBPL2)]TAF1
Transcription initiation factor TFIID subunit 1, also known as transcription initiation factor TFIID 250 kDa subunit (TAFII-250) or TBP-associated factor 250 kDa (p250), is a protein that in humans is encoded by the ''TAF1'' gene.
Function
Init ...
(TAFII250)
* TAF2 (CIF150)
* TAF3 (TAFII140)
* TAF4 (TAFII130/135)
* TAF4B (TAFII105)
* TAF5 (TAFII100)
* TAF6 (TAFII70/80)
* TAF7 (TAFII55)
* TAF8 (TAFII43)
* TAF9 (TAFII31/32)
* TAF9B (TAFII31L)
* TAF10 (TAFII30)
* TAF11 (TAFII28)
* TAF12 (TAFII20/15)
* TAF13 (TAFII18)
* TAF15 (TAFII68)
See also
* Eukaryotic transcription
Eukaryotic transcription is the elaborate process that eukaryotic cells use to copy genetic information stored in DNA into units of transportable complementary RNA replica. Gene transcription occurs in both eukaryotic and prokaryotic cells. Un ...
* General transcription factor
* Preinitiation complex
* Regulation of gene expression
Regulation of gene expression, or gene regulation, includes a wide range of mechanisms that are used by cells to increase or decrease the production of specific gene products (protein or RNA). Sophisticated programs of gene expression are wide ...
* RNA polymerase II holoenzyme
* TATA binding protein
The TATA-binding protein (TBP) is a general transcription factor that binds to a DNA sequence called the TATA box. This DNA sequence is found about 30 base pairs upstream of the transcription start site in some eukaryotic gene promoters.
T ...
* Transcription (genetics)
Transcription is the process of copying a segment of DNA into RNA for the purpose of gene expression. Some segments of DNA are transcribed into RNA molecules that can encode proteins, called messenger RNA (mRNA). Other segments of DNA are transc ...
References
External links
*
3D electron microscopy structures of TFIID from the EM Data Bank(EMDB)
Gene expression
Molecular genetics
Proteins
Transcription factors
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