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 synthesis artificially stimulate the replication of naturally occurring DNA, or to create artificial gene sequences. The process of DNA replication occurs typically as part of cell division, during interphase. A polymerase chain reaction is a form of enzymatic DNA synthesis in the laboratory, using cycles of repeated heating and cooling of the reaction for DNA melting and enzymatic replication of the DNA. Artificial gene synthesis is the process of synthesizing a gene "in vitro" without the need for initial template DNA samples. In 2010 J. Craig Venter and his team were the first to use entirely synthesized DNA to create a