Transcription factor: Difference between revisions

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In [[Gene expression|gene expression]], the transcription of [[DNA|DNA]] to [[RNA polymerase II|RNA]] is controlled by [[protein|proteins]] called transcription factors. In [[Eukaryote|eukaryotes]] there are 6 general transcription factors (GTFs): [[TFIIA|TFIIA]], [[TFIIB|TFIIB]], [[TFIID|TFIID]], [[TFIIE|TFIIE]], [[TFIIF|TFIIF]] and [[TFIIH|TFIIH]], each of which has a different role in regulating [[gene transcription|gene transcription]]. All GTFs are multi-subunit, except for TFIIB.  
In [[Gene expression|gene expression]], the transcription of [[DNA|DNA]] to [[RNA polymerase II|RNA]] is controlled by [[Protein|proteins]] called transcription factors. In [[Eukaryote|eukaryotes]] there are 6 general transcription factors (GTFs): [[TFIIA|TFIIA]], [[TFIIB|TFIIB]], [[TFIID|TFIID]], [[TFIIE|TFIIE]], [[TFIIF|TFIIF]] and [[TFIIH|TFIIH]], each of which has a different role in regulating [[Gene transcription|gene transcription]]. All GTFs are multi-subunit, except for TFIIB.  


The GTFs are involved in the [[Preinitiation complex|preinitiation complex]] (PIC) assembly which positions [[RNA polymerase II|RNA polymerase II]] and separates the template strand at the transcription start site through a number of steps as outlined:  
The GTFs are involved in the [[Preinitiation complex|preinitiation complex]] (PIC) assembly which positions [[RNA polymerase II|RNA polymerase II]] and separates the template strand at the transcription start site through a number of steps as outlined:  


#TFIIA facilitates and stabilises TFIID binding to the [[TATA box|TATA box]].
#TFIIA facilitates and stabilises TFIID binding to the [[TATA box|TATA box]].  
#TFIID recruits the single subunit factor TFIIB.
#TFIID recruits the single subunit factor TFIIB.  
#With this interaction, TFIIB recruits RNA polymerase II-TFIIF complex (TFIIF is joined to[[ RNA polymerase II|RNA polymerase II]] prior to this recruitment.)
#With this interaction, TFIIB recruits RNA polymerase II-TFIIF complex (TFIIF is joined to[[RNA polymerase II|RNA polymerase II]] before this recruitment.)  
#The recruitment of the RNA polymerase II-TFIIF allows TFIIE and then finally TFIIH to bind, completing the PIC assembly.
#The recruitment of the RNA polymerase II-TFIIF allows TFIIE and then finally TFIIH to bind, completing the PIC assembly.


This is known as the classical pathway, not all promoters are turned on in this way.
This is known as the classical pathway; not all promoters are turned on in this way.  
 
=== Function of GTFs  ===
 
'''TFIID''': Binds to the [[TATA box|TATA box]], recruits TFIIB
 
'''TFIIA''': Stabilizes TFIID binding, anti repression function
 
'''TFIIB''': Recruits RNA pol II-TFIIF, important for start site selection
 
'''TFIIF''': Stimulates [[Elongation|elongation]], destabilizes non specific RNA pol II-DNA interactions
 
'''TFIIE''': Recruits TFIIH and modulates TFIIH activity
 
'''TFIIH''': [[Promoter|Promoter]] melting and [[Clearance|clearance]], CTD [[Kinase|kinase]] activity, DNA repair coupling<ref>Harvey L, Arnold B, Chris A, Monty K, Anthony B, Hidde P, Angelika A, Kelsey C, 2016, Molecular Cell Biology, 8th edition, New York: W. H. Freeman</ref>
 
=== Reference  ===
 
<references />

Latest revision as of 19:16, 23 October 2017

In gene expression, the transcription of DNA to RNA is controlled by proteins called transcription factors. In eukaryotes there are 6 general transcription factors (GTFs): TFIIA, TFIIB, TFIID, TFIIE, TFIIF and TFIIH, each of which has a different role in regulating gene transcription. All GTFs are multi-subunit, except for TFIIB.

The GTFs are involved in the preinitiation complex (PIC) assembly which positions RNA polymerase II and separates the template strand at the transcription start site through a number of steps as outlined:

  1. TFIIA facilitates and stabilises TFIID binding to the TATA box.
  2. TFIID recruits the single subunit factor TFIIB.
  3. With this interaction, TFIIB recruits RNA polymerase II-TFIIF complex (TFIIF is joined toRNA polymerase II before this recruitment.)
  4. The recruitment of the RNA polymerase II-TFIIF allows TFIIE and then finally TFIIH to bind, completing the PIC assembly.

This is known as the classical pathway; not all promoters are turned on in this way.

Function of GTFs

TFIID: Binds to the TATA box, recruits TFIIB

TFIIA: Stabilizes TFIID binding, anti repression function

TFIIB: Recruits RNA pol II-TFIIF, important for start site selection

TFIIF: Stimulates elongation, destabilizes non specific RNA pol II-DNA interactions

TFIIE: Recruits TFIIH and modulates TFIIH activity

TFIIH: Promoter melting and clearance, CTD kinase activity, DNA repair coupling[1]

Reference

  1. ↑ Harvey L, Arnold B, Chris A, Monty K, Anthony B, Hidde P, Angelika A, Kelsey C, 2016, Molecular Cell Biology, 8th edition, New York: W. H. Freeman
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