Coactivator (genetics)

Coactivator (genetics)

A coactivator is a protein that increases gene expression by binding to an activator (or transcription factor) which contains a DNA binding domain. The coactivator is unable to bind DNA by itself.[1][2][3]

The coactivator can enhance transcription initiation by stabilizing the formation of the RNA polymerase holoenzyme enabling faster clearance of the promoter. Coactivators may control many other substeps of transcription, including elongation, RNA splicing, and termination and degradation of the coactivator-activator complex.

Some coactivators possess intrinsic histone acetyltransferase (HAT) activity, which acetylates histones and causes chromatin to relax in a limited region allowing increased access to the DNA. CBP and p300 are examples of coactivators with HAT activity. Numerous other enzyme activities have been reported among the 300 known coactivators for nuclear receptors.[4] The most well known of these are SRC-1, SRC-2, and SRC-3. Coactivators work in high molecular weight complexes of 6-10 coactivator and coactivator-associated proteins (termed co-coactivators).

The same coactivator will likely be used to increase transcription of many different genes, since it is the activator that provides the specificity to a particular sequence. Recent evidence indicates that coactivators may have diverse roles outside of transcription and that they may act as 'master genes' for regulating major cellular and metabolic growth processes.

In humans several dozen to several hundred coactivators are known, depending on the level of confidence with which the characterisation of a protein as a coactivator can be made.[5]


  1. ^ Näär AM, Lemon BD, Tjian R (2001). "Transcriptional coactivator complexes". Annu. Rev. Biochem. 70: 475–501. doi:10.1146/annurev.biochem.70.1.475. PMID 11395415. 
  2. ^ McKenna NJ, O'Malley BW (2002). "Minireview: nuclear receptor coactivators--an update". Endocrinology 143 (7): 2461–5. doi:10.1210/en.143.7.2461. PMID 12072374. 
  3. ^ Xu W (2005). "Nuclear receptor coactivators: the key to unlock chromatin". Biochem. Cell Biol. 83 (4): 418–28. doi:10.1139/o05-057. PMID 16094445. 
  4. ^ "Nuclear Receptor Signalling Atlas". Retrieved 2007-08-10. 
  5. ^ Schaefer U, Schmeier S, Bajic VB (Jan 2011). "TcoF-DB: dragon database for human transcription co-factors and transcription factor interacting proteins". Nucleic Acids Res. 39 (Database issue): D106–10. doi:10.1093/nar/gkq945. PMC 3013796. PMID 20965969. 

See also

External links

Wikimedia Foundation. 2010.

Look at other dictionaries:

  • NCo3 (Nuclear receptor coactivator 3) — Nuclear receptor coactivator 3 Nuclear receptor coactivator 3 (NCo3) est une protéine co activatrice de la transcription qui interragit avec les récepteurs nucléaires des hormones de type stéroïdien mais aussi avec d autres facteurs de… …   Wikipédia en Français

  • Nuclear receptor coactivator 3 — Structure de NCo3 Nuclear receptor coactivator 3 (NCo3) est une protéine co activatrice de la transcription qui interragit avec les récepteurs nucléaires des hormones de type stéroïdien mais aussi avec d autres facteurs de transcription tels TP52 …   Wikipédia en Français

  • Activator (genetics) — An activator is a DNA binding protein that regulates one or more genes by increasing the rate of transcription. The activator may increase transcription by virtue of a connected domain which assists in the formation of the RNA polymerase… …   Wikipedia

  • Terminator (genetics) — In genetics, a terminator, or transcription terminator is a section of genetic sequence that marks the end of gene or operon on genomic DNA for transcription. In prokaryotes, two classes of transcription terminators are known: Intrinsic… …   Wikipedia

  • Transcription (genetics) — Transcription is the process of creating a complementary RNA copy of a sequence of DNA.[1] Both RNA and DNA are nucleic acids, which use base pairs of nucleotides as a complementary language that can be converted back and forth from DNA to RNA by …   Wikipedia

  • Enhancer (genetics) — In genetics, an enhancer is a short region of DNA that can be bound with proteins (namely, the trans acting factors, much like a set of transcription factors) to enhance transcription levels of genes (hence the name) in a gene cluster. While… …   Wikipedia

  • Insulator (genetics) — For electrical insulator, see Insulator (Electrical). For other uses, see Insulation (disambiguation). An insulator is a genetic boundary element that plays two distinct roles in gene expression, either as an enhancer blocking element, or more… …   Wikipedia

  • Transcription coregulator — In the field of molecular biology, transcription coregulators are proteins that interact with transcription factors to either activate or repress the transcription of specific genes.cite journal |author=Glass CK, Rosenfeld MG|title=The… …   Wikipedia

  • List of types of proteins — A List of types of proteins is part of on going attempts to manage the large amounts of information concerning genes and proteins. Gene sequencing efforts and genome sequencing projects have led to the creation of many gene databases and attempts …   Wikipedia

  • Androgen insensitivity syndrome — Classification and external resources AIS results when the function of the androgen receptor (AR) is impaired. The AR protein (pictured) mediates the effects of androgens in the human body. ICD 10 E …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.