Description_x000D_ General description_x000D_ 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._x000D_ Biochem/physiol Actions_x000D_ Proliferating cell nuclear antigen (PCNA) has its main function in DNA replication and repair mechanism. Itsignificantly 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. This gene expression is known to offer resistance to chemotherapy. Expression of PCNA or cyclin or polymerase delta auxiliary protein is elevated in the nucleus during late G1 phase immediately before the onset of DNA synthesis, becoming maximal during S-phase and declining during G2 and M phases. PCNA/cyclin may act as an auxiliary protein of DNA polymerase-delta to play a fundamental role in the initiation of cell proliferation. Recombinant PCNA was expressed with a 6x His tag in sf9 insect cells and purified by proprietary chromatographic techniques._x000D_ Physical form_x000D_ Sterile filtered; 5 μg/5 μl in 50 mM Tris-Acetate, pH 7.5, 1 mM EDTA, and 20% Glycerol._x000D_ Reconstitution_x000D_ Centrifuge the vial prior to opening. Avoid freeze-thaw cycles.