Search results
Results from the WOW.Com Content Network
DNA ligase is a type of enzyme that facilitates the joining of DNA strands together by catalyzing the formation of a phosphodiester bond.It plays a role in repairing single-strand breaks in duplex DNA in living organisms, but some forms (such as DNA ligase IV) may specifically repair double-strand breaks (i.e. a break in both complementary strands of DNA).
Loading of Mcm proteins can only occur during the G 1 of the cell cycle, and the loaded complex is then activated during S phase by recruitment of the Cdc45 protein and the GINS complex to form the active Cdc45–Mcm–GINS (CMG) helicase at DNA replication forks. [62] [108] Mcm activity is required throughout the S phase for DNA replication.
S phase (Synthesis phase) is the phase of the cell cycle in which DNA is replicated, occurring between G 1 phase and G 2 phase. [1] Since accurate duplication of the genome is critical to successful cell division, the processes that occur during S-phase are tightly regulated and widely conserved.
During the synthesis phase (S-phase) of the eukaryotic cell cycle, DNA replication occurs. DNA ligase 1 is responsible for joining Okazaki fragments formed during discontinuous DNA synthesis on the DNA's lagging strand after DNA polymerase δ has replaced the RNA primer nucleotides with DNA nucleotides.
P. Heun et al., [48] (2001) tracked GFP-tagged replication foci in budding yeast cells and revealed that replication origins move constantly in G1 and S phase and the dynamics decreased significantly in S phase. [48] Traditionally, replication sites were fixed on spatial structure of chromosomes by nuclear matrix or lamins. The Heun's results ...
DNA ligase is an enzyme that joins together ends of DNA molecules. Although commonly represented as joining two pairs of ends at once, as in the ligation of restriction enzyme fragments, ligase can also join the ends on only one of the two strands (for example, when the other strand is already continuous or lacks a terminal phosphate necessary for ligation).
Since only a small number of double-strand breaks are tolerated, and only a small number can be repaired, enough ligation failures could be lethal to the cell. Further research implicates the supplementary role of proliferating cell nuclear antigen (PCNA) to DNA ligase I's function of joining Okazaki fragments. When the PCNA binding site on DNA ...
During step (2), damages in DNA of the germline can be removed by double-strand break repair. [41] In particular, double-strand breaks in one duplex DNA molecule can be accurately repaired using information from a homologous intact DNA molecule by the process of homologous recombination .