Fork rotation and DNA precatenation are restricted during DNA replication to prevent chromosomal instability

Schalbetter, Stephanie A, Mansoubi, Sahar, Chambers, Anna L, Downs, Jessica A and Baxter, Jonathan (2015) Fork rotation and DNA precatenation are restricted during DNA replication to prevent chromosomal instability. Proceedings of the National Academy of Sciences, 112 (33). E4565-E4570. ISSN 0027-8424

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Abstract

Faithful genome duplication and inheritance require the complete resolution of all intertwines within the parental DNA duplex. This is achieved by topoisomerase action ahead of the replication fork or by fork rotation and subsequent resolution of the DNA precatenation formed. Although fork rotation predominates at replication termination, in vitro studies have suggested that it also occurs frequently during elongation. However, the factors that influence fork rotation and how rotation and precatenation may influence other replication-associated processes are unknown. Here we analyze the causes and consequences of fork rotation in budding yeast. We find that fork rotation and precatenation preferentially occur in contexts that inhibit topoisomerase action ahead of the fork, including stable protein–DNA fragile sites and termination. However, generally, fork rotation and precatenation are actively inhibited by Timeless/Tof1 and Tipin/Csm3. In the absence of Tof1/Timeless, excessive fork rotation and precatenation cause extensive DNA damage following DNA replication. With Tof1, damage related to precatenation is focused on the fragile protein–DNA sites where fork rotation is induced. We conclude that although fork rotation and precatenation facilitate unwinding in hard-to-replicate contexts, they intrinsically disrupt normal chromosome duplication and are therefore restricted by Timeless/Tipin.

Item Type: Article
Keywords: DNA replication, topoisomerase, DNA topology, forkrotation, DNA catenation
Schools and Departments: School of Life Sciences > Sussex Centre for Genome Damage and Stability
Subjects: Q Science > QD Chemistry > QD0241 Organic chemistry > QD0415 Biochemistry
Depositing User: Gee Wheatley
Date Deposited: 13 Aug 2015 09:37
Last Modified: 09 Mar 2021 14:16
URI: http://sro.sussex.ac.uk/id/eprint/56104

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