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
Cell-free fetal DNA pregnancies complicated by preeclampsia have significantly higher levels of cffDNA that those in normal pregnancies. This holds true for early onset preeclampsia. New generation sequencing may be used to yield a whole genome sequence from cffDNA. This raises ethical questions. However, the utility of the procedure may increase as clear associations between specific genetic variants and disease states are discovered. Cell-free fetal DNA Cell-free fetal DNA (cffDNA) is fetal DNA which circulates freely in the maternal blood. Maternal blood is sampled by venipuncture. Analysis of cffDNA is a method of non-invasive prenatal diagnosis frequently ordered for pregnant women of advanced