Replisome speed determines the efficiency of the Tus-Ter replication termination barrier.

Autor: Elshenawy MM; Division of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal 23955, Saudi Arabia., Jergic S; Centre for Medical &Molecular Bioscience, Illawarra Health &Medical Research Institute and University of Wollongong, New South Wales 2522, Australia., Xu ZQ; Centre for Medical &Molecular Bioscience, Illawarra Health &Medical Research Institute and University of Wollongong, New South Wales 2522, Australia., Sobhy MA; Division of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal 23955, Saudi Arabia., Takahashi M; Division of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal 23955, Saudi Arabia., Oakley AJ; Centre for Medical &Molecular Bioscience, Illawarra Health &Medical Research Institute and University of Wollongong, New South Wales 2522, Australia., Dixon NE; Centre for Medical &Molecular Bioscience, Illawarra Health &Medical Research Institute and University of Wollongong, New South Wales 2522, Australia., Hamdan SM; Division of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal 23955, Saudi Arabia.
Jazyk: angličtina
Zdroj: Nature [Nature] 2015 Sep 17; Vol. 525 (7569), pp. 394-8. Date of Electronic Publication: 2015 Aug 31.
DOI: 10.1038/nature14866
Abstrakt: In all domains of life, DNA synthesis occurs bidirectionally from replication origins. Despite variable rates of replication fork progression, fork convergence often occurs at specific sites. Escherichia coli sets a 'replication fork trap' that allows the first arriving fork to enter but not to leave the terminus region. The trap is set by oppositely oriented Tus-bound Ter sites that block forks on approach from only one direction. However, the efficiency of fork blockage by Tus-Ter does not exceed 50% in vivo despite its apparent ability to almost permanently arrest replication forks in vitro. Here we use data from single-molecule DNA replication assays and structural studies to show that both polarity and fork-arrest efficiency are determined by a competition between rates of Tus displacement and rearrangement of Tus-Ter interactions that leads to blockage of slower moving replisomes by two distinct mechanisms. To our knowledge this is the first example where intrinsic differences in rates of individual replisomes have different biological outcomes.
Databáze: MEDLINE
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