DNA Replication: Mammalian

Abstract It is well known that deoxyribonucleic acid (DNA) replication occurs at the replication fork, whereby the parent strand of DNA unwinds and two daughter strands are formed, which are subsequently synthesized in a leading and lagging strand manner. Furthermore, many proteins and enzymes are involved in initiation of DNA replication, and the synthesis of DNA, as well as the structural component of the nuclear matrix, which allows for attachment of replication proteins. It is also known that replication of mammalian DNA is a very complicated and highly regulated process, requiring strict regulation, along with many different proteins and enzymes. Although there is a wealth of information regarding basic DNA synthesis, there is still much more information to learn regarding the machinery involved in initiation of DNA replication, DNA synthesis and, ultimately, DNA replication. Key Concepts: The proteins thus far identified in mammalian cell DNA replication include the MCM helicase complex, DNA pol α‐primase, PCNA, RFC, DNA pol δ, FEN1, RPA, DNA ligase I, topoisomerase I and II and RNAse H. The manner and timing by which mammalian DNA replication occurs is highly regulated and occurs mostly in the G1 phase of the cell cycle. Telomeres maintain the integrity of the genome by protecting the ends of the chromosomes from degradation and preventing end‐to‐end fusions of chromosomes. Mammalian cells have many levels of tight regulation for the replication of telomeres to maintain genome stability and cell survival. The nuclear matrix plays a vital role in initiation, chromosome replication and regulation. Proteins necessary for DNA replication come together to form ‘replication factories’ within the nucleus.