WAPL-Dependent Repair of Damaged DNA Replication Forks Underlies Oncogene-Induced Loss of Sister Chromatid Cohesion

Abstract

Highlights d Cohesion loss is a common feature of cancer cells d DNA replication stress induces cohesion loss d The cohesin remover WAPL is essential in replication stress conditions d WAPL promotes repair and restart of a broken replication fork

Non-redundant roles in sister chromatid cohesion of the DNA helicase DDX11 and the SMC3 acetyl transferases ESCO1 and ESCO2

“…The duplex or quadruplex resolving capacities of DDX11 helicases may contribute to SCC by facilitating loading of the second strand into cohesin rings, which was reported to require single stranded DNA [63]. Alternatively, secondary DNA structures that are normally substrates of DDX11 may be prone to breakage when DDX11 is absent, requiring repair and WAPL/PDS5-dependent cohesin removal to provide access of repair factors to the break site [68]. Both DDX11 [46][47][48][49][50] and ESCO2 [37][38][39] interact with multiple replication fork components, indicating that they promote cohesin loading and cohesion establishment in synchrony with DNA replication fork passage.…”

“…CRISPR-Cas9 was used to construct DDX11 and ESCO2 knockouts in RPE1 cells. The generation of RPE1-hTERT_TetOn-Cas9_TP53KO cells is also described in a currently submitted manuscript [68]. Briefly, Cas9 cDNA was cloned into the pLVX-Tre3G plasmid (Clontech) and lentiviral Tre3G-Cas9 and Tet3G particles were produced in HEK293T cells using the Lenti-X HT packaging system (Clontech).…”

The RAD51 recombinase protects mitotic chromatin in human cells

“…These proposed mechanisms include CDK1-mediated activation of nucleases such as MUS81 to trigger break-induced MiDAS and WAPLmediated removal of cohesin (Minocherhomji et al, 2015). Interestingly, WAPL is also proposed to promote RAD51-dependent replication restart at broken forks (Benedict et al, 2020). We also envisage that the removal of several chromatin-associated proteins in interphase, such as the transcriptional machinery and the cohesin complex at chromosome arms, may prepare the chromatin environment to accommodate MiDAS.…”

“…The resulting RAD51 nucleoprotein filament then mediates strand invasion to initiate HR (Baumann and West, 1998). This mechanism enables RAD51 to catalyse HR not only at two-ended DSBs, but also at one-ended DSBs arising from collapsed replication forks, thereby promoting replication restart through break-induced replication (BIR) (Benedict et al, 2020;Hashimoto et al, 2011;Natsume et al, 2017).…”

“…It has been proposed that these factors work in concert at under-replicated CFSs to complete replication and/or promote mitotic DNA synthesis (MiDAS) via a BIR-like mechanism, triggered by nucleolytic cleavage at stalled replication forks (Dilley et al, 2016;Min et al, 2017;Minocherhomji et al, 2015). While several reports in higher eukaryotes suggest that RAD51 catalyses BIR, MiDAS at CFSs and telomeres appears to be primarily dependent on RAD52 to complete replication in early mitosis (Benedict et al, 2020;Bhowmick et al, 2016;Costantino et al, 2014;Min et al, 2017;Natsume et al, 2017).…”