Mediator of RNA polymerase II transcription subunit 21 is an enzyme that in humans is encoded by the MED21 gene. The Mediator is a multiprotein coactivator that is required by DNA-binding transcription factors for transcriptional activation of polymerase II (see MIM 180660)-transcribed genes. MED21 is a Mediator subunit predicted to reside in the middle module and appears to be a core subunit found in nearly all Mediator preparations (summary by Sato et al., 2004 [PubMed 15175163]).[supplied by OMIM]. Sequence Note: removed 1 base from the 3' end that did not align to the reference genome assembly. Publication Note: This RefSeq record includes a subset of the publications that are available for this gene. Please see the Gene record to access additional publications.
Component of the Mediator complex, a coactivator involved in the regulated transcription of nearly all RNA polymerase II-dependent genes. Mediator functions as a bridge to convey information from gene-specific regulatory proteins to the basal RNA polymerase II transcription machinery. Mediator is recruited to promoters by direct interactions with regulatory proteins and serves as a scaffold for the assembly of a functional preinitiation complex with RNA polymerase II and the general transcription factors.