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Eukaryotic DNA replication is a conserved mechanism that restricts DNA replication to once per cell ... Required for initiation and elongation steps of DNA ...
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.
The replication of bacteriophage T4 DNA upon infection of E. coli is a well-studied DNA replication system. During the period of exponential DNA increase at 37°C, the rate of elongation is 749 nucleotides per second. [ 11 ]
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.
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]
MCM2-7 is required for both DNA replication initiation and elongation; its regulation at each stage is a central feature of eukaryotic DNA replication. [3] During G1 phase, the two head-to-head Mcm2-7 rings serve as the scaffold for the assembly of the bidirectional replication initiation complexes at the replication origin.
In eukaryotes, which have a much higher diversity of DNA polymerases, the low-processivity initiating enzyme is called Pol α, and the high-processivity extension enzymes are Pol δ and Pol ε. Both prokaryotes and eukaryotes must "trade" bound polymerases to make the transition from initiation to elongation. This process is called polymerase ...
For eukaryotes specifically, the mechanism of DNA replication elongation between the leading and lagging strand differs. On the lagging strand, nicks exist between Okazaki fragments and are easily recognizable by the DNA mismatch repair machinery prior to ligation. Due to the continuous replication that occurs on the leading strand, the ...