Mediator of RNA polymerase II transcription subunit 27 (MED27)

Mediator of RNA polymerase II transcription subunit 27 (MED27) is a protein encoded by the MED27 gene that serves as a subunit of the Mediator complex, a multi-protein transcriptional coactivator essential for RNA polymerase II-dependent gene expression[1][4][5]. MED27 forms part of the CRSP (cofactor required for SP1 activation) complex and interacts with a wide array of transcription factors to help direct transcriptional initiation, acting as a bridge between gene-specific regulatory proteins and the core transcriptional machinery. It is crucial for assembly of the preinitiation complex and efficient activation by certain transcription factors such as SP1, as well as for interaction with nuclear hormone receptors like the thyroid hormone receptor[4]. MED27 has an essential, ubiquitous role in human development, and genetic disruption causes a severe, variably expressed neurodevelopmental syndrome marked by spasticity, cataracts, and cerebellar hypoplasia[7]. Overexpression or abnormal function of MED27 also contributes to the progression of certain cancers, including breast cancer, where it promotes metastasis and supports cancer cell "stemness"[2][6]. No direct approved drugs are known to target MED27, likely due to its fundamental cellular role and associated safety concerns.

Other names

CRSP34CRSP8CRSP complex subunit 8TRAP37MED3Cofactor required for Sp1 transcriptional activation subunit 8p37 TRAP/SMCC/PC2 subunitTranscriptional coactivator CRSP34CRAP34NEDSCAC34kDa epididymis secretory sperm binding protein