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 laddering along with DNA laddering such as TEM and TUNEL. With recent improvements to DNA laddering, DNA laddering has become a more reliable, and reasonable technique to use when detecting apoptosis. It is also important to note that DNA laddering occurs differently depending on the type of cell, so there may be slight changes in the process of DNA laddering depending on the cell that is being investigated. DNA laddering DNA laddering is a feature that can be observed when DNA fragments, resulting from apoptotic DNA fragmentation, are visualized after separation by gel electrophoresis. It was first described in 1980 by