Proteomic Analyses of the Eukaryotic Replication Machinery

DNA replication in a human cell involves hundreds of proteins that copy the DNA accurately and completely each cell division cycle. In addition to the core DNA copying machine (the replisome), accessory proteins work to respond to replication stress, correct errors, and repackage the DNA into appropriate chromatin structures. New proteomic tools have been invented in the past few years to facilitate the purification, identification, and quantification of the replication, chromatin maturation, and replication stress response machineries. These tools, including iPOND (isolation of proteins on nascent DNA) and NCC (nascent chromatin capture), have yielded discoveries of new proteins involved in these processes and insights into the dynamic regulatory processes ensuring genome and chromatin integrity. In this review, I will introduce these experimental approaches and examine how they have been utilized to define the replication fork proteome.