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TFIID (also known as [[transcription factor|transcription factor]] II D) is a multi-subunit general transcription factor involved in the formation of the pre-initiation complex <ref>Hartl, D.L., Jones, E.W., 2009. Genetics; Analysis of Genes and Genomes. 7th ed. Jones and Bartlett Publications.</ref>&nbsp;TFIID binding is involved in the first step of transcription in [[eukaryotes|eukaryotes]]. It later goes on to associate with [[RNA polymerase II|RNA polymerase II]], which is used to transcribe [[mRNA|mRNA]].  
<p>TFIID (also known as <a href="Transcription factor">transcription factor</a> II D) is a multi-subunit general transcription factor involved in the formation of the pre-initiation complex <span class="fck_mw_ref" _fck_mw_customtag="true" _fck_mw_tagname="ref">Hartl, D.L., Jones, E.W., 2009. Genetics; Analysis of Genes and Genomes. 7th ed. Jones and Bartlett Publications.</span>&#160;TFIID binding is involved in the first step of transcription in <a href="Eukaryotes">eukaryotes</a>. It later goes on to associate with <a href="RNA polymerase II">RNA polymerase II</a>, which is used to transcribe <a href="MRNA">mRNA</a>.  
 
</p>
== Structure  ==
<h2> Structure  </h2>
 
<p>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 <a href="TATA-binding protein">TATA-binding protein</a> (TBP) and a complex of 10 <a href="TBP-associated factors">TBP-associated factors</a> (TAFs). The TBP&#160;region is required by all three <a href="RNA polymerase">RNA polymerases</a>, whereas the TAF regions differ by RNA&#160;polymerase <span class="fck_mw_ref" _fck_mw_customtag="true" _fck_mw_tagname="ref">Gupta, P.K., 2007. Genetics; Classical to Modern. 1st ed. Rastogi Publications</span>. TBP is composed of 180 amino acid residues and is highly conserved throughout evolution <span class="fck_mw_ref" _fck_mw_customtag="true" _fck_mw_tagname="ref">White, R.J., 2001. Gene Transcription; Mechanisms and Control. 1st ed. Blackwell Science Ltd.</span>.
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&nbsp;region is required by all three [[RNA_polymerase|RNA polymerases]], whereas the TAF regions differ by RNA&nbsp;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>.
</p>
 
<h2> Mechanism  </h2>
== Mechanism  ==
<p>TBP recognises and binds to the <a href="Tata box">TATA box</a> in eukaryotic genes as&#160;per it's main function <span class="fck_mw_ref" _fck_mw_customtag="true" _fck_mw_tagname="ref">Hartl, D.L., Jones, E.W., 2009. Genetics; Analysis of Genes and Genomes. 7th ed. Jones and Bartlett Publications.</span>. The TAF subunits are not required in genes with a <a href="TATA promoter">TATA promoter</a>, however they do have a role in reducing transcription levels by dissociating TBP from the TATA&#160;box <span class="fck_mw_ref" _fck_mw_customtag="true" _fck_mw_tagname="ref">White, R.J., 2001. Gene Transcription; Mechanisms and Control. 1st ed. Blackwell Science Ltd.</span>.  
 
</p><p>Unlike other <a href="Proteins">proteins</a> with <a href="DNA binding domains">DNA binding domains</a>, TBP notably alters the structure of <a href="DNA">DNA</a> when bound via twisting and bending it <span class="fck_mw_ref" _fck_mw_customtag="true" _fck_mw_tagname="ref">White, R.J., 2001. Gene Transcription; Mechanisms and Control. 1st ed. Blackwell Science Ltd.</span>. This creates a <a href="Hydrophobic">hydrophobic</a> exposed region for TFIIB to join to in the next step of pre-initiation complex formation <span class="fck_mw_ref" _fck_mw_customtag="true" _fck_mw_tagname="ref">White, R.J., 2001. Gene Transcription; Mechanisms and Control. 1st ed. Blackwell Science Ltd.</span>.  
TBP recognises and binds to the [[Tata_box|TATA box]] in eukaryotic genes as&nbsp;per it's main function <ref>Hartl, D.L., Jones, E.W., 2009. Genetics; Analysis of Genes and Genomes. 7th ed. Jones and Bartlett Publications.</ref>. The TAF subunits are not required in genes with a [[TATA promoter|TATA promoter]], however they do have a role in reducing transcription levels by dissociating TBP from the TATA&nbsp;box <ref>White, R.J., 2001. Gene Transcription; Mechanisms and Control. 1st ed. Blackwell Science Ltd.</ref>.  
</p>
 
<h2> Function  </h2>
Unlike other [[proteins|proteins]] with [[DNA binding domains|DNA binding domains]], TBP notably alters the structure of [[DNA|DNA]] when bound via twisting and bending it <ref>White, R.J., 2001. Gene Transcription; Mechanisms and Control. 1st ed. Blackwell Science Ltd.</ref>. This creates a [[hydrophobic|hydrophobic]] exposed region for TFIIB to join to in the next step of pre-initiation complex formation <ref>White, R.J., 2001. Gene Transcription; Mechanisms and Control. 1st ed. Blackwell Science Ltd.</ref>.  
<p>While the main function of the TBP region of TFIID is to bind to the TATA&#160;box on DNA, the TAF&#160;proteins have a range of functions. Notably, TAFII250 acts as a <a href="Scaffold protein">scaffold protein</a> and has <a href="Kinase">kinase</a> activity, and TAFII150 binds to DNA downstream of the TATA box <span class="fck_mw_ref" _fck_mw_customtag="true" _fck_mw_tagname="ref">White, R.J., 2001. Gene Transcription; Mechanisms and Control. 1st ed. Blackwell Science Ltd.</span>. Furthermore, TAFII80, TAFII31 and TAFII20 have show similar features and structures to histones H4, H3 and H2b respectively <span class="fck_mw_ref" _fck_mw_customtag="true" _fck_mw_tagname="ref">White, R.J., 2001. Gene Transcription; Mechanisms and Control. 1st ed. Blackwell Science Ltd.</span>.  
 
</p>
== Function  ==
<h2> References </h2>
 
<p><span class="fck_mw_references" _fck_mw_customtag="true" _fck_mw_tagname="references" /><br />
While the main function of the TBP region of TFIID is to bind to the TATA&nbsp;box on DNA, the TAF&nbsp;proteins have a range of functions. Notably, TAFII250 acts as a [[scaffold protein|scaffold protein]] and has [[Kinase|kinase]] activity, and TAFII150 binds to DNA downstream of the TATA box <ref>White, R.J., 2001. Gene Transcription; Mechanisms and Control. 1st ed. Blackwell Science Ltd.</ref>. Furthermore, TAFII80, TAFII31 and TAFII20 have show similar features and structures to histones H4, H3 and H2b respectively <ref>White, R.J., 2001. Gene Transcription; Mechanisms and Control. 1st ed. Blackwell Science Ltd.</ref>.  
</p>
 
== References ==
 
<references /><br>

Revision as of 14:01, 23 October 2015

TFIID (also known as <a href="Transcription factor">transcription factor</a> II D) is a multi-subunit general transcription factor involved in the formation of the pre-initiation complex Hartl, D.L., Jones, E.W., 2009. Genetics; Analysis of Genes and Genomes. 7th ed. Jones and Bartlett Publications. TFIID binding is involved in the first step of transcription in <a href="Eukaryotes">eukaryotes</a>. It later goes on to associate with <a href="RNA polymerase II">RNA polymerase II</a>, which is used to transcribe <a href="MRNA">mRNA</a>.

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 <a href="TATA-binding protein">TATA-binding protein</a> (TBP) and a complex of 10 <a href="TBP-associated factors">TBP-associated factors</a> (TAFs). The TBP region is required by all three <a href="RNA polymerase">RNA polymerases</a>, whereas the TAF regions differ by RNA polymerase Gupta, P.K., 2007. Genetics; Classical to Modern. 1st ed. Rastogi Publications. TBP is composed of 180 amino acid residues and is highly conserved throughout evolution White, R.J., 2001. Gene Transcription; Mechanisms and Control. 1st ed. Blackwell Science Ltd..

Mechanism

TBP recognises and binds to the <a href="Tata box">TATA box</a> in eukaryotic genes as per it's main function Hartl, D.L., Jones, E.W., 2009. Genetics; Analysis of Genes and Genomes. 7th ed. Jones and Bartlett Publications.. The TAF subunits are not required in genes with a <a href="TATA promoter">TATA promoter</a>, however they do have a role in reducing transcription levels by dissociating TBP from the TATA box White, R.J., 2001. Gene Transcription; Mechanisms and Control. 1st ed. Blackwell Science Ltd..

Unlike other <a href="Proteins">proteins</a> with <a href="DNA binding domains">DNA binding domains</a>, TBP notably alters the structure of <a href="DNA">DNA</a> when bound via twisting and bending it White, R.J., 2001. Gene Transcription; Mechanisms and Control. 1st ed. Blackwell Science Ltd.. This creates a <a href="Hydrophobic">hydrophobic</a> exposed region for TFIIB to join to in the next step of pre-initiation complex formation White, R.J., 2001. Gene Transcription; Mechanisms and Control. 1st ed. Blackwell Science Ltd..

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 <a href="Scaffold protein">scaffold protein</a> and has <a href="Kinase">kinase</a> activity, and TAFII150 binds to DNA downstream of the TATA box White, R.J., 2001. Gene Transcription; Mechanisms and Control. 1st ed. Blackwell Science Ltd.. Furthermore, TAFII80, TAFII31 and TAFII20 have show similar features and structures to histones H4, H3 and H2b respectively White, R.J., 2001. Gene Transcription; Mechanisms and Control. 1st ed. Blackwell Science Ltd..

References


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