Proliferating cell nuclear antigen originally identified as an antigen that is expressed in the nuclei of cells during the DNA synthesis phase of the cell cycle. Part of the protein was sequenced and that sequence was used to allow isolation of a cDNA clone. PCNA helps hold DNA polymerase epsilon (Pol ε) to DNA. PCNA is clamped to DNA through the action of replication factor C (RFC), which is a heteropentameric member of the AAA+ class of ATPases. Expression of PCNA is under the control of E2F transcription factor-containing complexes. Since DNA polymerase epsilon is involved in resynthesis of excised damaged DNA strands during
DNA polymerase epsilon RPA. PCNA and RFC function as anchor and direct DNA polymerase epsilon onto the DNA template. DNA polymerase epsilon DNA polymerase epsilon is a member of the DNA polymerase family of enzymes found in eukaryotes. It is composed of the following four subunits: POLE (central catalytic unit), POLE2 (subunit 2), POLE3 (subunit 3), and POLE4 (subunit 4). Recent evidence suggests that it plays a major role in leading strand DNA synthesis and nucleotide and base excision repair. Research had conducted to study nucleotide excision repair DNA synthesis by DNA polymerase epsilon in the presence of PCNA (proliferating cell nuclear antigen),