General description

PCNA (proliferating cell nuclear antigen) gene is mapped to human chromosome 20p12.3 and encodes a scaffolding protein. PCNA is a homotrimeric protein known to localize in the nucleus. The PCNA ring has a central cavity that is large enough to allow the dsDNA to slide freely along it. PCNA is a nuclear protein whose appearance correlates with the proliferative state of the cells and is a cofactor of DNA polymerase delta.

Biochem/physiol Actions

Proliferating cell nuclear antigen (PCNA) significantly maintains the longevity of mature neutrophil granulocytes. Upregulation of the PCNA gene is observed in cervical squamous cell carcinoma. PCNA supports cell survival by elevating metabolism flux. PCNA expression is known to offer resistance to chemotherapy. PCNA is a homotrimer and helps increase the processivity 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. Immunofluorescence studies have shown that p300 may play a role in DNA repair synthesis through its interaction with PCNA. In vitro and in vivo p300 forms a complex with PCNA that does not depend on the S phase of the cell cycle and stimulates DNA synthesis in vitro. PCNA interacts with the Williams syndrome transcription factor (WSTF) allowing it to target to DNA replication foci, that then allows recruitment of SNF2H.