rCCNC (cyclin C) is a member of the cyclin family of proteins. This protein interacts with cyclin-dependent kinase 8 (CDK8) and induces the phophorylation of the carboxy-terminal domain of the large subunit of RNA polymerase II. The level of mRNAs for this protein peaks in the G1 phase of the cell cycle. It has been shown that a non-cdk8-associated cellular pool of CCNC combines with cdk3 to stimulate pRb phosphorylation at S807/811 during the G0/G1 transition, and that this phosphorylation is required for cells to exit GO efficiently. Other results have shown that a marked elevated immunoreactivity of CCNC was found both in neurons and astrocytes in Alzheimer's disease (AD). Increased levels of CCNC RNA were detected by ribonuclease protection assay (RPA) in severe AD cases and colocalization of CCNC and its preferred binding partner, CDK8, was only observed in astrocytes but not in neurons.
Recombinant CNCC is expressed in E. coli as a full-length protein fused to a proprietary 16-Kd tag (a 6xHis tag is located at the very N-terminal end).
1. Gene Expressions Specifically Detected in Motor Neurons (Dynactin 1, Early Growth Response 3, Acetyl-CoA Transporter, Death Receptor 5, and Cyclin C) Differentially Correlate to Pathologic Markers in Sporadic Amyotrophic Lateral Sclerosis. J Neuropathol Exp Neurol 2007 Jul;66(7):617-627.