Transcription factor II A

Last updated
general transcription factor IIA, 1, 19/37kDa
Identifiers
Symbol GTF2A1
NCBI gene 2957
HGNC 4646
OMIM 600520
RefSeq NM_201595
UniProt P52655
Other data
Locus Chr. 14 q31
general transcription factor IIA, 2, 12kDa
Identifiers
SymbolGTF2A2
NCBI gene 2958
HGNC 4647
OMIM 600519
RefSeq NM_004492
UniProt P52657
Other data
Locus Chr. 15 q21.3

Transcription factor TFIIA is a nuclear protein involved in the RNA polymerase II-dependent transcription of DNA. [1] TFIIA is one of several general (basal) transcription factors (GTFs) that are required for all transcription events that use RNA polymerase II. Other GTFs include TFIID, a complex composed of the TATA binding protein TBP and TBP-associated factors (TAFs), as well as the factors TFIIB, TFIIE, TFIIF, and TFIIH. Together, these factors are responsible for promoter recognition and the formation of a transcription preinitiation complex (PIC) capable of initiating RNA synthesis from a DNA template.

Contents

Functions

TFIIA interacts with the TBP subunit of TFIID and aids in the binding of TBP to TATA-box containing promoter DNA. [2] [3] Interaction of TFIIA with TBP facilitates formation of and stabilizes the preinitiation complex. Interaction of TFIIA with TBP also results in the exclusion of negative (repressive) factors that might otherwise bind to TBP and interfere with PIC formation. TFIIA also acts as a coactivator for some transcriptional activators, assisting with their ability to increase, or activate, transcription. The requirement for TFIIA in vitro transcription systems has been variable, and it can be considered either as a GTF and/or a loosely associated TAF-like coactivator. Genetic analysis in yeast has shown that TFIIA is essential for viability.

Structure

TFIIA is a heterodimer with two subunits: one large unprocessed (subunit 1, or alpha/beta; gene name GTF2A1 ) and one small (subunit 2, or gamma; gene name GTF2A2 ). [4] [5] It was originally believed to be a heterotrimer of an alpha (p35), a beta (p19) and a gamma subunit (p12). In humans, the sizes of the encoded proteins are approximately 55  kD and 12 kD. Both genes are present in species ranging from humans to yeast, and their protein products interact to form a complex composed of a beta barrel domain and an alpha helical bundle domain. It is the N-terminal and C-terminal regions of the large subunit that participate in interactions with the small subunit. These regions are separated by another domain whose sequence is always present in large subunits from various species but whose size varies and whose sequence is poorly conserved. A second gene encoding a large TFIIA subunit has been found in some higher eukaryotes. This gene, ALF/TFIIAtau (gene name GTF2A1LF ) is expressed only in oocytes and spermatocytes, suggesting it has a TFIIA-like regulatory role for gene expression only in germ cells.

Related Research Articles

Transcription preinitiation complex Complex of proteins necessary for gene transcription in eukaryotes and archaea

The preinitiation complex is a complex of approximately 100 proteins that is necessary for the transcription of protein-coding genes in eukaryotes and archaea. The preinitiation complex positions RNA polymerase II at gene transcription start sites, denatures the DNA, and positions the DNA in the RNA polymerase II active site for transcription.

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 RNA. GTFs, RNA polymerase, and the mediator constitute the basic transcriptional apparatus that first bind to the promoter, then start transcription. GTFs are also intimately involved in the process of gene regulation, and most are required for life.

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 gene promoters.

Transcription factor II F (TFIIF) is one of several general transcription factors that make up the RNA polymerase II preinitiation complex.

TAF7

Transcription initiation factor TFIID subunit 7 also known as TAFII55 is a protein that in humans is encoded by the TAF7 gene.

TAF9 Protein-coding gene in the species Homo sapiens

TAF9 RNA polymerase II, TATA box binding protein (TBP)-associated factor, 32kDa, also known as TAF9, is a protein that in humans is encoded by the TAF9 gene.

TAF12

Transcription initiation factor TFIID subunit 12 is a protein that in humans is encoded by the TAF12 gene.

TAF4

Transcription initiation factor TFIID subunit 4 is a protein that in humans is encoded by the TAF4 gene.

TAF2

Transcription initiation factor TFIID subunit 2 is a protein that in humans is encoded by the TAF2 gene.

TAF10

Transcription initiation factor TFIID subunit 10 is a protein that in humans is encoded by the TAF10 gene.

TAF5

Transcription initiation factor TFIID subunit 5 is a protein that in humans is encoded by the TAF5 gene.

TAF11

Transcription initiation factor TFIID subunit 11 also known as TAFII28, is a protein that in humans is encoded by the TAF11 gene.

TAF15

TATA-binding protein-associated factor 2N is a protein that in humans is encoded by the TAF15 gene.

TAF13

Transcription initiation factor TFIID subunit 13 is a protein that in humans is encoded by the TAF13 gene.

TAF8

Transcription initiation factor TFIID subunit 8 is a protein that in humans is encoded by the TAF8 gene.

TAF6L

TAF6-like RNA polymerase II p300/CBP-associated factor-associated factor 65 kDa subunit 6L is an enzyme that in humans is encoded by the TAF6L gene.

GTF2A1

Transcription initiation factor IIA subunit 1 is a protein that in humans is encoded by the GTF2A1 gene.

TAF9B

Transcription initiation factor TFIID subunit 9B is a protein that in humans is encoded by the TAF9B gene.

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 proteins known as SRB proteins.

TBP-associated factor Protein domains

The TBP-associated factors (TAF) are proteins that associate with the TATA-binding protein in transcription initiation. It is a part of the transcription initiation factor TFIID multimeric protein complex. It also makes up many other factors, including SL1. They mediate the formation of the transcription preinitiation complex, a step preceding transcription of DNA to RNA by RNA polymerase II.

References

  1. ↑ Høiby T, Zhou H, Mitsiou DJ, Stunnenberg HG (2007). "A facelift for the general transcription factor TFIIA". Biochimica et Biophysica Acta (BBA) - Gene Structure and Expression. 1769 (7–8): 429–36. doi:10.1016/j.bbaexp.2007.04.008. PMID   17560669.
  2. ↑ Tang H, Sun X, Reinberg D, Ebright RH (February 1996). "Protein-protein interactions in eukaryotic transcription initiation: structure of the preinitiation complex". Proceedings of the National Academy of Sciences of the United States of America. 93 (3): 1119–24. Bibcode:1996PNAS...93.1119T. doi: 10.1073/pnas.93.3.1119 . PMC   40041 . PMID   8577725.
  3. ↑ Louder RK, He Y, López-Blanco JR, Fang J, Chacón P, Nogales E (March 2016). "Structure of promoter-bound TFIID and model of human pre-initiation complex assembly". Nature. 531 (7596): 604–9. Bibcode:2016Natur.531..604L. doi:10.1038/nature17394. PMC   4856295 . PMID   27007846.
  4. ↑ DeJong J, Roeder RG (November 1993). "A single cDNA, hTFIIA/alpha, encodes both the p35 and p19 subunits of human TFIIA". Genes & Development. 7 (11): 2220–34. doi: 10.1101/gad.7.11.2220 . PMID   8224848.
  5. ↑ Ozer J, Moore PA, Bolden AH, Lee A, Rosen CA, Lieberman PM (October 1994). "Molecular cloning of the small (gamma) subunit of human TFIIA reveals functions critical for activated transcription". Genes & Development. 8 (19): 2324–35. doi: 10.1101/gad.8.19.2324 . PMID   7958899.
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