In vitro Assays for Eukaryotic Leading/Lagging Strand DNA Replication

The eukaryotic replisome is a multiprotein complex that duplicates DNA. The replisome is sculpted to couple continuous leading strand synthesis with discontinuous lagging strand synthesis, primarily carried out by DNA polymerases ε and δ, respectively, along with helicases, polymerase α-primase, DNA sliding clamps, clamp loaders and many other proteins. We have previously established the mechanisms by which the polymerases ε and δ are targeted to their 'correct' strands, as well as quality control mechanisms that evict polymerases when they associate with an 'incorrect' strand. Here, we provide a practical guide to differentially assay leading and lagging strand replication in vitro using pure proteins.