DNA replication machinery of the mammalian cell

The process of DNA replication in mammalian cells is highly complex and has several unique features that distinguish it from simpler prokaryotic systems. The study of mammalian DNA replication lagged behind that of prokaryotes for many years. This was because of the lack of a reliable and efficient mammalian cell-based in vitro DNA replication system. In 1984, the first mammalian-based DNA replication system that initiated DNA synthesis successfully in vitro was developed. The employment of the mammalian in vitro DNA replication system has led to the identification of several DNA replication proteins. This article describes the current knowledge regarding the proteins mediating mammalian DNA replication, as well as how they are proposed to function during DNA synthesis. There is also a discussion of the role the mammalian cell nuclear architecture plays in DNA replication. The evidence for the existence of an organized DNA replication machine in mammalian cells is also presented.