Transcription factor II D (TF_IID) is one of several

general transcription factor General transcription factors (GTFs), also known as basal transcriptional factors, are a class of protein transcription factors that bind to specific sites ( promoter) on DNA to activate transcription of genetic information from DNA to messenger ...

s that make up the

RNA polymerase II RNA polymerase II (RNAP II and Pol II) is a multiprotein complex that transcribes DNA into precursors of messenger RNA (mRNA) and most small nuclear RNA (snRNA) and microRNA. It is one of the three RNAP enzymes found in the nucleus of euka ...

preinitiation complex.

RNA polymerase II holoenzyme RNA polymerase II holoenzyme is a form of eukaryotic RNA polymerase II that is recruited to the promoters of protein-coding genes in living cells. It consists of RNA polymerase II, a subset of general transcription factors, and regulatory protein ...

is a form of

eukaryotic Eukaryotes () are organisms whose cells have a nucleus. All animals, plants, fungi, and many unicellular organisms, are Eukaryotes. They belong to the group of organisms Eukaryota or Eukarya, which is one of the three domains of life. Bacte ...

that is recruited to the promoters of

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, res ...

-coding genes in living cells. It consists of

, 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 of genetic information from DNA to messenger RNA, by binding to a specific DNA sequence. The f ...

s, and

regulatory protein 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 w ...

s known as SRB proteins. Before the start of transcription, the transcription Factor II D (TF_IID) complex binds to the

core promoter In genetics, a promoter is a sequence of DNA to which proteins bind to initiate transcription of a single RNA transcript from the DNA downstream of the promoter. The RNA transcript may encode a protein (mRNA), or can have a function in and of ...

DNA of the gene through specific recognition of promoter sequence motifs, including the

TATA box In molecular biology, the TATA box (also called the Goldberg–Hogness box) is a sequence of DNA found in the core promoter region of genes in archaea and eukaryotes. The bacterial homolog of the TATA box is called the Pribnow box which has ...

Initiator An initiator can refer to: * A person who instigates something. * Modulated neutron initiator, a neutron source used in some nuclear weapons ** Initiator, an Explosive booster ** Initiator, the first Nuclear chain reaction * Pyrotechnic 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 The TATA-binding protein (TBP) is a general transcription factor that binds specifically 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 gen ...

Associated Factors (TBP-associated factors, or TAFs). In a test tube, only TBP is necessary for transcription at promoters that contain a

. 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-a ...

) 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 Transcription initiation factor TFIID subunit 2 is a protein that in humans is encoded by the ''TAF2'' gene. Initiation of transcription by RNA polymerase II requires the activities of more than 70 polypeptides. The protein that coordinates thes ...

(CIF150) *

TAF3 Transcription initiation factor TFIID subunit 3 is a protein that in humans is encoded by the ''TAF3'' gene In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." mea ...

(TAFII140) *

TAF4 Transcription initiation factor TFIID subunit 4 is a protein that in humans is encoded by the ''TAF4'' gene. Function Initiation of transcription by RNA polymerase II requires the activities of more than 70 polypeptides. The protein that coord ...

(TAFII130/135) *

TAF4B Transcription initiation factor TFIID subunit 4B is a protein that in humans is encoded by the ''TAF4B'' gene. Function TATA-binding protein associated factors (TAFs) participate, with TATA binding protein (TBP; MIM 600075), in the formation o ...

(TAFII105) * TAF5 (TAFII100) * TAF6 (TAFII70/80) *

TAF7 Transcription initiation factor TFIID subunit 7 also known as TAFII55 is a protein that in humans is encoded by the ''TAF7'' gene. Function The intronless gene for this transcription coactivator is located between the protocadherin beta and g ...

(TAFII55) * TAF8 (TAFII43) * TAF9 (TAFII31/32) *

TAF9B Transcription initiation factor TFIID subunit 9B is a protein that in humans is encoded by the ''TAF9B'' gene. Initiation of transcription by RNA polymerase II requires the activities of more than 70 polypeptides. The protein that coordinates the ...

(TAFII31L) * TAF10 (TAFII30) *

TAF11 Transcription initiation factor TFIID subunit 11 also known as TAFII28, is a protein that in humans is encoded by the ''TAF11'' gene. Function Initiation of transcription by RNA polymerase II requires the activities of more than 70 polypeptid ...

(TAFII28) * TAF12 (TAFII20/15) *

TAF13 Transcription initiation factor TFIID subunit 13 is a protein that in humans is encoded by the ''TAF13'' gene. Function Initiation of transcription by RNA polymerase II requires the activities of more than 70 polypeptides. The protein that co ...

(TAFII18) *

TAF15 TATA-binding protein-associated factor 2N is a protein that in humans is encoded by the ''TAF15'' gene. Function Initiation of transcription by RNA polymerase II requires the activities of more than 70 polypeptides. The protein that coordinates ...

(TAFII68)

References

External links

*
3D electron microscopy structures of TFIID from the EM Data Bank(EMDB)
Gene expression Molecular genetics Proteins Transcription factors {{Genetics-stub

Functions

Structure

See also

References

External links