TRAIP drives replisome disassembly and mitotic DNA repair synthesis at sites of incomplete DNA replication.

Remi Sonneville,Saskia Hoffmann,Karim Labib,Rahul Bhowmick,Ian D Hickson,Niels Mailand

doi:10.7554/elife.48686

Remi Sonneville, Saskia Hoffmann + Show 4 more

Open Access

https://doi.org/10.7554/elife.48686

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Abstract

The faithful segregation of eukaryotic chromosomes in mitosis requires that the genome be duplicated completely prior to anaphase. However, cells with large genomes sometimes fail to complete replication during interphase and instead enter mitosis with regions of incompletely replicated DNA. These regions are processed in early mitosis via a process known as mitotic DNA repair synthesis (MiDAS), but little is known about how cells switch from conventional DNA replication to MiDAS. Using the early embryo of the nematode Caenorhabditis elegans as a model system, we show that the TRAIP ubiquitin ligase drives replisome disassembly in response to incomplete DNA replication, thereby providing access to replication forks for other factors. Moreover, TRAIP is essential for MiDAS in human cells, and is important in both systems to prevent mitotic segregation errors. Our data indicate that TRAIP is a master regulator of the processing of incomplete DNA replication during mitosis in metazoa.

Highlights

Chromosome duplication in eukaryotes is initiated from many origins of DNA replication on each chromosome, leading to the progression of DNA replication forks across the genome until fork convergence induces DNA replication termination
Cells with large genomes sometimes fail to complete replication during interphase and instead enter mitosis with regions of incompletely replicated DNA. These regions are processed in early mitosis via a process known as mitotic DNA repair synthesis (MiDAS), but little is known about how cells switch from conventional DNA replication to MiDAS
Monitoring replisome disassembly during mitosis is difficult in eukaryotic cells that have been exposed to DNA replication stress, since the S-phase checkpoint response usually blocks mitotic entry under such conditions

Summary

Introduction

Chromosome duplication in eukaryotes is initiated from many origins of DNA replication on each chromosome, leading to the progression of DNA replication forks across the genome until fork convergence induces DNA replication termination. Using the early embryo of C. elegans as a model system, we previously identified a mitotic pathway for CMG disassembly that requires CDC-48_UFD-1_NPL-4, and is able to remove any posttermination replisomes that escape the normal disassembly process during S-phase (Sonneville et al, 2017) This mitotic pathway for replisome disassembly requires a ubiquitin ligase known as TRAIP (Deng et al, 2019; Priego Moreno et al, 2019), which is important for genome integrity in human cells (Feng et al, 2016; Harley et al, 2016; Hoffmann et al, 2016; Soo Lee et al, 2016) and is required to remove the replisome from converged DNA replication forks during the repair of inter-strand DNA crosslinks in extracts of Xenopus laevis eggs (Wu et al, 2019).

Results and discussion

Materials and methods

Funding Funder Medical Research Council