Cyclin C Antibody

Cyclin-C (CCNC) forms the CDK8 module with CDK8, MED12, MED13, which decreases transcriptional activation when combined with the Mediator complex. The Mediator complex is a large protein complex composed of almost 30 different MED proteins that regulates transcription of nearly all RNA polymerase II (RNApII)-dependent genes, conveying information from gene-specific regulatory proteins. Mediator serves as a scaffold for the assembly of the functional preinitiation complex that includes RNApII. Cyclin-C-bound CDK8 phosphorylates the C-terminal domain of the large subunit of RNApII, inhibiting the formation of a transcription initiation complex. Cyclin-C is phosphorylated upon DNA damage, probably by ATM or ATR.