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The major enzymatic functions carried out at the replication fork are well conserved from prokaryotes to eukaryotes, but the replication machinery in eukaryotic DNA replication is a much larger complex, coordinating many proteins at the site of replication, forming the replisome.
Eukaryotes initiate DNA replication at multiple points in the chromosome, so replication forks meet and terminate at many points in the chromosome. Because eukaryotes have linear chromosomes, DNA replication is unable to reach the very end of the chromosomes. Due to this problem, DNA is lost in each replication cycle from the end of the chromosome.
DNA is a duplex formed by two anti-parallel strands. Following Meselson-Stahl, the process of DNA replication is semi-conservative, whereby during replication the original DNA duplex is separated into two daughter strands (referred to as the leading and lagging strand templates). Each daughter strand becomes part of a new DNA duplex.
Rolling circle replication (RCR) is a process of unidirectional nucleic acid replication that can rapidly synthesize multiple copies of circular molecules of DNA or RNA, such as plasmids, the genomes of bacteriophages, and the circular RNA genome of viroids. Some eukaryotic viruses also replicate their DNA or RNA via the rolling circle mechanism.
Single-strand binding proteins stabilize the newly formed replication bubble and interact with the DnaG primase. DnaG recruits the replicative DNA polymerase III, and replication begins. In eukaryotes, MCM heterohexamer is phosphorylated by CDC7 and CDK, which displaces Cdc6 and recruits MCM10. MCM10 cooperates with MCM2-7 in the recruitment of ...
In eukaryotic cells (cells that package their DNA within a nucleus), chromosomes consist of very long linear double-stranded DNA molecules. During the S-phase of each cell cycle ( Figure 1 ), all of the DNA in a cell is duplicated in order to provide one copy to each of the daughter cells after the next cell division.
More than five decades ago, Jacob, Brenner, and Cuzin proposed the replicon hypothesis to explain the regulation of chromosomal DNA synthesis in E. coli. [18] The model postulates that a diffusible, trans-acting factor, a so-called initiator, interacts with a cis-acting DNA element, the replicator, to promote replication onset at a nearby origin.
A licensing factor is a protein or complex of proteins that allows an origin of replication to begin DNA replication at that site. Licensing factors primarily occur in eukaryotic cells, since bacteria use simpler systems to initiate replication. However, many archaea use homologues of eukaryotic licensing factors to initiate replication. [1]