Bidirectional eukaryotic DNA replication is established by quasi-symmetrical helicase loading
Year: 2017
Type: article
Abstract: Bidirectional replication from eukaryotic DNA replication origins requires the loading of two ring-shaped minichromosome maintenance (MCM) helicases around DNA in opposite orientations. MCM loading is orchestrated by binding of the origin recognition complex (ORC) to DNA, but how ORC coordinates symmetrical MCM loading is unclear. We used natural budding yeast DNA replication origins and synthetic DNA sequences to show that efficient MCM loading requires binding of two ORC molecules to two ORC binding sites. The relative orientation of these sites, but not the distance between them, was found to be critical for MCM loading in vitro and origin function in vivo. We propose that quasi-symmetrical loading of individual MCM hexamers by ORC and directed MCM translocation into double hexamers acts as a unifying mechanism for the establishment of bidirectional replication in archaea and eukaryotes.
Source: Science
Authors: Gideon Coster, John F. X. Diffley
Institution: The Francis Crick Institute
Language: English
Topic: DNA Repair Mechanisms
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W2737463560