TFIID: Difference between revisions
No edit summary |
|||
| Line 3: | Line 3: | ||
== Structure == | == Structure == | ||
TFIID is comprised of a [[TATA-binding protein|TATA-binding protein]] (TBP) and a complex of 10 [[TBP-associated factors|TBP-associated factors]] (TAFs). The TBP region is required by all three [[RNA_polymerase|RNA polymerases]], whereas the TAF regions differ by RNA polymerase <ref>Gupta, P.K., 2007. Genetics; Classical to Modern. 1st ed. Rastogi Publications</ref>. TBP is composed of 180 amino acid residues and is highly conserved throughout evolution <ref>White, R.J., 2001. Gene Transcription; Mechanisms and Control. 1st ed. Blackwell Science Ltd.</ref>. | Using [electron microscopy] to study both human and [yeast] TFIID's had led scientists discover that both have a trilobular structure. TFIID is comprised of a [[TATA-binding protein|TATA-binding protein]] (TBP) and a complex of 10 [[TBP-associated factors|TBP-associated factors]] (TAFs). The TBP region is required by all three [[RNA_polymerase|RNA polymerases]], whereas the TAF regions differ by RNA polymerase <ref>Gupta, P.K., 2007. Genetics; Classical to Modern. 1st ed. Rastogi Publications</ref>. TBP is composed of 180 amino acid residues and is highly conserved throughout evolution <ref>White, R.J., 2001. Gene Transcription; Mechanisms and Control. 1st ed. Blackwell Science Ltd.</ref>. | ||
== Mechanism == | == Mechanism == | ||
Revision as of 14:01, 23 October 2015
TFIID (also known as transcription factor II D) is a multi-subunit general transcription factor involved in the formation of the pre-initiation complex [1] TFIID binding is involved in the first step of transcription in eukaryotes. It later goes on to associate with RNA polymerase II, which is used to transcribe mRNA.
Structure
Using [electron microscopy] to study both human and [yeast] TFIID's had led scientists discover that both have a trilobular structure. TFIID is comprised of a TATA-binding protein (TBP) and a complex of 10 TBP-associated factors (TAFs). The TBP region is required by all three RNA polymerases, whereas the TAF regions differ by RNA polymerase [2]. TBP is composed of 180 amino acid residues and is highly conserved throughout evolution [3].
Mechanism
TBP recognises and binds to the TATA box in eukaryotic genes as per it's main function [4]. The TAF subunits are not required in genes with a TATA promoter, however they do have a role in reducing transcription levels by dissociating TBP from the TATA box [5].
Unlike other proteins with DNA binding domains, TBP notably alters the structure of DNA when bound via twisting and bending it [6]. This creates a hydrophobic exposed region for TFIIB to join to in the next step of pre-initiation complex formation [7].
Function
While the main function of the TBP region of TFIID is to bind to the TATA box on DNA, the TAF proteins have a range of functions. Notably, TAFII250 acts as a scaffold protein and has kinase activity, and TAFII150 binds to DNA downstream of the TATA box [8]. Furthermore, TAFII80, TAFII31 and TAFII20 have show similar features and structures to histones H4, H3 and H2b respectively [9].
References
- ↑ Hartl, D.L., Jones, E.W., 2009. Genetics; Analysis of Genes and Genomes. 7th ed. Jones and Bartlett Publications.
- ↑ Gupta, P.K., 2007. Genetics; Classical to Modern. 1st ed. Rastogi Publications
- ↑ White, R.J., 2001. Gene Transcription; Mechanisms and Control. 1st ed. Blackwell Science Ltd.
- ↑ Hartl, D.L., Jones, E.W., 2009. Genetics; Analysis of Genes and Genomes. 7th ed. Jones and Bartlett Publications.
- ↑ White, R.J., 2001. Gene Transcription; Mechanisms and Control. 1st ed. Blackwell Science Ltd.
- ↑ White, R.J., 2001. Gene Transcription; Mechanisms and Control. 1st ed. Blackwell Science Ltd.
- ↑ White, R.J., 2001. Gene Transcription; Mechanisms and Control. 1st ed. Blackwell Science Ltd.
- ↑ White, R.J., 2001. Gene Transcription; Mechanisms and Control. 1st ed. Blackwell Science Ltd.
- ↑ White, R.J., 2001. Gene Transcription; Mechanisms and Control. 1st ed. Blackwell Science Ltd.