PCNA (polymerase delta auxiliary protein) is essential for DNA replication and is involved in DNA excision and mismatch repair pathways. PCNA binds to the CDK inhibitor p21, the structure-specific endonucleases Fen1 and XPG, and DNA cytosine 5-methyltransferase (MCMT). PCNA is a potentially useful marker of cells with proliferative potential and for identifying the proliferation status of tumor tissue (i.e. relevant to prognosis). PCNA is a marker for cells in early G1 phase and S phase of the cell cycle. PCNA is found in the nucleus and is a cofactor of DNA polymerase delta, and acts as a homotrimer and helps increase the processing of leading strand synthesis during DNA replication. In response to DNA damage, PCNA is ubiquitinated and is involved in the RAD6-dependent DNA repair pathway. Two transcript variants encoding the same protein have been found for PCNA. Pseudogenes of PCNA have been described on chromosome 4 and on the X chromosome.
Cyclin; DNA polymerase delta auxiliary protein; HGCN8729; MGC8367; PCNA; Proliferating cell nuclear antigen