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Mediator complex subunit 23
Symbols MED23 ; ARC130; CRSP130; CRSP133; CRSP3; DRIP130; MRT18; SUR-2; SUR2
External IDs OMIM605042 MGI1917458 HomoloGene3552 ChEMBL: 4146 GeneCards: MED23 Gene
RNA expression pattern
PBB GE CRSP3 218846 at tn.png
More reference expression data
Species Human Mouse
Entrez 9439 70208
Ensembl ENSG00000112282 ENSMUSG00000019984
UniProt Q9ULK4 Q80YQ2
RefSeq (mRNA) NM_001270521 NM_001166416
RefSeq (protein) NP_001257450 NP_001159888
Location (UCSC) Chr 6:
131.9 – 131.95 Mb
Chr 10:
24.87 – 24.91 Mb
PubMed search [1] [2]

Mediator of RNA polymerase II transcription subunit 23 is an enzyme that in humans is encoded by the MED23 gene.[1][2]

The activation of gene transcription is a multistep process that is triggered by factors that recognize transcriptional enhancer sites in DNA. These factors work with co-activators to direct transcriptional initiation by the RNA polymerase II apparatus. The protein encoded by this gene is a subunit of the CRSP (cofactor required for SP1 activation) complex, which, along with TFIID, is required for efficient activation by SP1. This protein is also a component of other multisubunit complexes e.g. thyroid hormone receptor-(TR-) associated proteins which interact with TR and facilitate TR function on DNA templates in conjunction with initiation factors and cofactors. This protein also acts as a metastasis suppressor. Two alternatively spliced transcript variants encoding different isoforms have been described for this gene.[2]


CRSP3 has been shown to interact with Estrogen receptor alpha,[3] CEBPB[4] and Cyclin-dependent kinase 8.[3][5]


  1. ^ Ryu S, Zhou S, Ladurner AG, Tjian R (Feb 1999). "The transcriptional cofactor complex CRSP is required for activity of the enhancer-binding protein Sp1". Nature 397 (6718): 446–50. doi:10.1038/17141. PMID 9989412. 
  2. ^ a b "Entrez Gene: CRSP3 cofactor required for Sp1 transcriptional activation, subunit 3, 130kDa". 
  3. ^ a b Kang, Yun Kyoung; Guermah Mohamed; Yuan Chao-Xing; Roeder Robert G (Mar 2002). "The TRAP/Mediator coactivator complex interacts directly with estrogen receptors alpha and beta through the TRAP220 subunit and directly enhances estrogen receptor function in vitro". Proc. Natl. Acad. Sci. U.S.A. (United States) 99 (5): 2642–7. doi:10.1073/pnas.261715899. ISSN 0027-8424. PMC 122401. PMID 11867769. 
  4. ^ Mo, Xianming; Kowenz-Leutz Elisabeth, Xu Hong, Leutz Achim (Jan 2004). "Ras induces mediator complex exchange on C/EBP beta". Mol. Cell (United States) 13 (2): 241–50. doi:10.1016/S1097-2765(03)00521-5. ISSN 1097-2765. PMID 14759369. 
  5. ^ Wang, G; Cantin G T; Stevens J L; Berk A J (Jul 2001). "Characterization of mediator complexes from HeLa cell nuclear extract". Mol. Cell. Biol. (United States) 21 (14): 4604–13. doi:10.1128/MCB.21.14.4604-4613.2001. ISSN 0270-7306. PMC 87123. PMID 11416138. 

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