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The replication fork is a structure that forms within the long helical DNA during DNA replication. It is produced by enzymes called helicases that break the hydrogen bonds that hold the DNA strands together in a helix.
The process of semiconservative replication for the site of DNA replication is a fork-like DNA structure, the replication fork, where the DNA helix is open, or unwound, exposing unpaired DNA nucleotides for recognition and base pairing for the incorporation of free nucleotides into double-stranded DNA. [3]
This image is a derivative work of the following images: File:DNA_replication_en.svg licensed with PD-user . 2009-06-01T14:09:19Z Bibi Saint-Pol 691x336 (113021 Bytes) {{Information |Description= {{en|DNA replication or DNA synthesis is the process of copying a double-stranded DNA molecule.
We also know that the replication-timing program changes during development, along with changes in the expression of genes. For many decades now, it has been known that replication timing is correlated with the structure of chromosomes. For example, female mammals have two X chromosomes. One of these is genetically active, while the other is ...
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.
The crystal structure of the Ter DNA-Tus protein complex (A) showing the nonblocking and the fork-blocking faces of Tus. (B) A cross-sectional view of the helicase-arresting surface. Replication of the DNA separating the opposing replication forks leaves the completed chromosomes joined as ‘catenanes’ or topologically interlinked circles ...
The replicator is the entire DNA sequence (including, but not limited to the origin of replication) required to direct the initiation of DNA replication. The initiator is the protein that recognizes the replicator and activates replication initiation.
Control of the DNA replication system ensures that the genome is replicated only once per cycle; over-replication induces DNA damage. Deregulation of DNA replication is a key factor in genomic instability during cancer development. [3] This highlights the specificity of DNA synthesis machinery in vivo. Various means exist to artificially ...