DNA replication


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DNA replication

The formation of new and, hopefully, identical copies of complete genomes. DNA replication occurs every time a cell divides to form two daughter cells. Under the influence of enzymes, DNA unwinds and the two strands separate over short lengths to form numerous replication forks, each of which is called a replicon. The separated strands are temporarily sealed with protein to prevent re-attachment. A short RNA sequence called a primer is formed for each strand at the fork. These primers provide a free 3'-OH end on which the new complementary sequence can be formed along the strand. The LEADING STRAND is synthesized continuously in the 5’ to 3’ direction, working towards the fork direction with removal of the RNA primers as the parental duplex is unwound. The LAGGING STRAND is synthesized discontinuously in the opposite direction as short fragments called Okazaki fragments. Lagging strand synthesis requires extension of the primer, then removal of the primers and gap filling. At least 20 different enzymes and factors, including DNA helicases, DNA polymerases, RNA primases, DNA TOPOISOMERASES and DNA ligases are involved in the complex process of DNA replication.

DNA replication

see DNA.
References in periodicals archive ?
To ensure that the information contained in the DNA is not altered during the process of cell division, cells have evolved checkpoints that monitor the correct execution of DNA replication. Studies from the laboratory of Dr Vincenzo DAngiolella have revealed how the balance of the building blocks composing the DNA molecule is maintained in the cell cycle and how this is coordinated with the execution of checkpoints.
The preclinical work published in the manuscript demonstrates NVN1000's durable inhibition of high-risk HPV-18 DNA replication in a three-dimensional human skin culture model.
It may even open the door to an anti-ageing pill, which triggers DNA replication each time a cell divides.
Summary: Natural products play a significant role in the design of anticancer drugs acting on DNA replication. Different classes of natural products include meroterpene, phenol, flavonoid and coumestan isolated from Psoralea corylifolia plant have been found active against cancer disease.
Furthermore, HPV reactivates host DNA replication in these differentiated cells such that the replication proteins and substrates become available to support viral DNA amplification.
The process of genome duplication is called DNA replication. DNA replication is extremely complex, said OMRF scientist Christopher Sansam.
Normally, our cells have in place a number of strategies to address these obstacles and then successfully continue with DNA replication. In the case of those with HGPS, however, Gonzalo found that progerin causes these strategies to falter.
Among their topics are methane seeps in a changing climate, the shallow submarine hot vent system off the Greek island of Milos as a natural laboratory for studying hydrothermal geomicrobiology, life in serpentinite hosted alkaline springs, microbial nitrogen processes at submarine hydrothermal vents, and multiplication is vexation: a genomic perspective on cell division and DNA replication in the large sulfur bacteria.
As cells create duplicate copies of their genetic material, a lesion or other obstacle can block DNA replication, potentially derailing a cell's ability to reproduce.
The company is also advancing SRA141, a potent, selective, orally bioavailable small molecule inhibitor of Cell division cycle 7 (Cdc7 ) kinase, a key regulator of DNA replication involved in the DDR network, making it a compelling emerging target for the potential treatment of a broad range of tumor types.
All living organisms need a DNA replication mechanism and it has been conserved in the three domains of life throughout evolutionary process (Schwob, 2004).
The primary functions of chromatin are: package DNA into a more compact, denser shape: reinforce the DNA macromolecule to allow mitosis: prevent DNA damage; and control gene expression and DNA replication. The primary protein components of chromatin are histones that compact the DNA.