Mediator复合物是由大约25-30蛋白组成,并且被认为通过作为在RNA polymerase II (RNAPII)装置和转录因子之间的一个分子桥从而有助于转录激活(1)。Mediator通过转录因子被招募到靶基因,并且在启动子上RNAPII转录复合物转录和稳定性中以及转录后RNAPII招募的激活起到重要作用(1-5)。Mediator复合物也在chromatin loops的产生中有重要作用,该环的产生作为结合到末端增强子的转录因子和结合到近端启动子RNAPII之间相互作用的结果,并且在活化的转录期间去维持正确的染色质结构(6-8)。
Species predicted to react based on 100% sequence homology:Hamster, Bovine, Pig, Horse
Specificity / Sensitivity
MED12 Antibody recognizes endogenous levels of total MED12 protein.
Source / Purification
Polyclonal antibodies are produced by immunizing animals with a synthetic peptide corresponding to residues near the carboxy terminus of human MED12 protein. Antibodies are purified by protein A and peptide affinity chromatography.
Background
The Mediator complex consists of about 25-30 proteins and is thought to facilitate transcription activation by acting as a molecular bridge between the RNA polymerase II (RNAPII) machinery and transcription factors (1). Mediator is recruited to target genes by transcription factors and plays an essential role in the recruitment and stabilization of the RNAPII transcription complex at promoters, as well as the activation of transcription post RNAPII recruitment (1-5). The Mediator complex also plays an important role in creating ‘chromatin loops’ that occur as a result of interactions between the transcription factor bound at distal enhancers and RNAPII bound at the proximal promoter, and works to sustain proper chromatin architecture during active transcription (6-8).
MED12 is part of the CDK8 submodule of the Mediator complex and is required for the stable interaction of this module with the rest of the Mediator complex (1,9). The CDK8 module has been shown to be both a negative and positive regulator of transcription depending on the gene context. The CDK8 module may repress transcription by inhibiting the ability of Mediator to recruit RNAPII (10). In addition, the MED12 subunit can recruit the methyltransferase G9a to methylate histone H3K9 to repress a subset of neuronal genes in non-neuronal cells (11). MED12 and the CDK8 module can also positively regulate transcription of Wnt-responsive genes through its interaction with β-catenin, and p53-regulated genes upon UV-induced DNA damage (1,9,12).