轉錄的啟動部分受稱為預啟動復合物的大型蛋白質裝配的控制。 這種預啟動復合體的一個組成部分是一個稱為Mediator的1.2 MDa蛋白聚集體。 該介體組分與包含該基因編碼的蛋白質，介體復合物亞基12（MED12）以及MED13，CDK8激酶和細胞周期蛋白C的CDK8亞復合體結合。 和重新激發率。 MED12蛋白對于激活CDK8激酶至關重要。 該基因的缺陷會導致X連鎖的Opitz-Kaveggia綜合征（也稱為FG綜合征）和Lujan-Fryns綜合征。 [由RefSeq提供，2009年8月]
The initiation of transcription is controlled in part by a large protein assembly known as the preinitiation complex. A component of this preinitiation complex is a 1.2 MDa protein aggregate called Mediator. This Mediator component binds with a CDK8 subcomplex which contains the protein encoded by this gene, mediator complex subunit 12 (MED12), along with MED13, CDK8 kinase, and cyclin C. The CDK8 subcomplex modulates Mediator-polymerase II interactions and thereby regulates transcription initiation and reinitation rates. The MED12 protein is essential for activating CDK8 kinase. Defects in this gene cause X-linked Opitz-Kaveggia syndrome, also known as FG syndrome, and Lujan-Fryns syndrome. [provided by RefSeq, Aug 2009]