Nuclear structure and DNA replication

DNA replication is a highly conserved process among eukaryotes where it occ urs within a unique organelle-the nucleus. The importance of this structure is indicated by the fact that assembly of prereplication complexes on cell ular chromatin is delayed until mitosis is completed and a nuclear structur e has formed. Although nuclear structure is dispensable for DNA replication in vitro, it does appear to play a role in vivo by regulating the concentr ation of proteins required to initiate DNA replication, by facilitating the assembly or activity of DNA replication forks, and by determining where in the genome initiation of DNA replication occurs.