RNA polymerase II transcription mediator complex subunit 9
This family of Med9 proteins is conserved in yeasts. It forms part of the middle region of Mediator. Med9 has two functional domains. The species-specific amino-terminal half (aa 1-63) plays a regulatory role in transcriptional regulation, whereas this well-conserved carboxy-terminal half (aa 64-149) has a more fundamental function involved in direct binding to the amino-terminal portions of Med4 and Med7 and the assembly of Med9 into the Middle module. Also, some unidentified factor(s) in med9 extracts may impact the binding of TFIID to the promoter.