Editing Origin of replication (section)

{{short description|Sequence in a genome}}
[[File:Origins_of_DNA_replication_Figure_1.jpg|thumb|300x300px|Models for bacterial ('''A''') and eukaryotic ('''B''') DNA replication initiation. '''A''') Circular bacterial chromosomes contain a ''cis''-acting element, the replicator, that is located at or near replication origins. ''i'') The replicator recruits initiator proteins in a DNA sequence-specific manner, which results in melting of the DNA helix and loading of the replicative helicase onto each of the single DNA strands (''ii''). ''iii'') Assembled replisomes bidirectionally replicate DNA to yield two copies of the bacterial chromosome. '''B''') Linear eukaryotic chromosomes contain many replication origins. Initiator binding (''i'') facilitates replicative helicase loading (''ii'') onto duplex DNA to license origins. ''iii'') A subset of loaded helicases is activated for replisome assembly. Replication proceeds bidirectionally from origins and terminates when replication forks from adjacent active origins meet (''iv'').]]

The '''origin of replication''' (also called the '''replication origin''') is a particular sequence in a [[genome]] at which replication is initiated.<ref>{{cite book | veditors = Wagner EK, Hewlett M, Bloom D, Camerini D | chapter = Technical Glossary | chapter-url = http://www.blackwellpublishing.com/wagner/glossary.pdf |title=Basic Virology |date=2008 |publisher=Blackwell Publishing |location=Malden, MA |isbn=978-1-4051-4715-6 |edition=3rd}}</ref> Propagation of the genetic material between generations requires timely and accurate duplication of DNA by [[semiconservative replication]] prior to cell division to ensure each daughter cell receives the full complement of [[chromosome]]s.<ref name="Ekundayo et al">{{cite journal | vauthors = Ekundayo B, Bleichert F | title = Origins of DNA replication | journal = PLOS Genetics | volume = 15 | issue = 9 | pages = e1008320 | date = September 2019 | pmid = 31513569 | pmc = 6742236 | doi = 10.1371/journal.pgen.1008320 | doi-access = free }} [[File:CC-BY icon.svg|50px]] Material was copied from this source, which is available under a [https://creativecommons.org/licenses/by/4.0/ Creative Commons Attribution 4.0 International License].</ref> This can either involve the [[DNA replication|replication]] of DNA in living organisms such as prokaryotes and eukaryotes, or that of [[DNA virus|DNA]] or [[RNA virus|RNA]] in viruses, such as [[double-stranded RNA viruses]].<ref>{{cite journal | vauthors = Hulo C, de Castro E, Masson P, Bougueleret L, Bairoch A, Xenarios I, Le Mercier P | title = ViralZone: a knowledge resource to understand virus diversity | journal = Nucleic Acids Research | volume = 39 | issue = Database issue | pages = D576-82 | date = January 2011 | pmid = 20947564 | pmc = 3013774 | doi = 10.1093/nar/gkq901 }}</ref> Synthesis of daughter strands starts at discrete sites, termed replication origins, and proceeds in a bidirectional manner until all genomic DNA is replicated. Despite the fundamental nature of these events, organisms have evolved surprisingly divergent strategies that control replication onset.<ref name="Ekundayo et al"/> Although the specific replication origin organization structure and recognition varies from species to species, some common characteristics are shared.