Mediator Complex Subunit 9 (MED9)

MED9 is a member of the mediator complex of proteins that promote activation of RNA polymerase II through direct interactions with transcription factorsMED9 encodes a deduced 146-amino acid protein, with a C-terminal region of approximately 80 amino acids that is highly conserved from mammals to insects. Two short domains of MED9 also show similarity to the yeast mediator protein Cse2.FLAG-tagged mouse MED9 copurifies with the mammalian mediator complex. In vitro and in vivo coimmunoprecipitation experiments showed that mouse Med9 binds directly to Trap36, another mediator complex subunit. The authors noted that the Med9-Trap36 interaction suggests that Med9 and Cse2 are functionally related, as Cse2 binds the Trap36 ortholog Med4.