Slx4 and Rtt107 control checkpoint signalling and DNA resection at double-strand breaks

Abstract

The DNA damage checkpoint pathway is activated in response to DNA lesions and replication stress to preserve genome integrity. However, hyper-activation of this surveillance system is detrimental to the cell, because it might prevent cell cycle re-start after repair, which may also lead to senescence. Here we show that the scaffold proteins Slx4 and Rtt107 limit checkpoint signalling at a persistent double-strand DNA break (DSB) and at uncapped telomeres. We found that Slx4 is recruited within a few kilobases of an irreparable DSB, through the interaction with Rtt107 and the multi-BRCT domain scaffold Dpb11. In the absence of Slx4 or Rtt107, Rad9 binding near the irreparable DSB is increased, leading to robust checkpoint signalling and slower nucleolytic degradation of the 5′ strand. Importantly, in slx4Δ sae2Δ double mutant cells these phenotypes are exacerbated, causing a severe Rad9-dependent defect in DSB repair. Our study sheds new light on the molecular mechanism that coordinates the processing and repair of DSBs with DNA damage checkpoint signalling, preserving genome integrity.

Slx4 scaffolding in homologous recombination and checkpoint control: lessons from yeast

“…Efficient recruitment of Slx4 to DNA lesions requires interactions with both Rtt107 and Dpb11 (Fig. 3c) (Cussiol et al 2015; Dibitetto et al 2016). Recent work demonstrated that recognition of γ H2A and phospho-Ddc1 T602 via BRCT-5/6 of Rtt107 and BRCT-3/4 of Dpb11, respectively, is required for dampening of Rad53 signaling (Cussiol et al 2015).…”

“…In addition, resection of double strand breaks also generates ssDNA::dsDNA junctions that should support Slx4 recruitment. Indeed, ChIP approaches were successfully used to detect recruitment of Slx4 to an HO-inducible DSB (Dibitetto et al 2016; Leung et al 2016; Toh et al 2010). Congruent with these findings, functional studies also reveal important roles for Slx4 in the response to DSBs (Dibitetto et al 2016).…”

Mecanismos De Reparo Aos Danos No Dna Nos Pontos De Checagem Do Ciclo Celular

“…Esse sistema é gerenciado por metabólitos e proteínas que modulam as transições do ciclo celular e influenciam a estabilidade ou as atividades de outras proteínas (DIBITETTO et al, 2016).…”

Multi-BRCT scaffolds use distinct strategies to support genome maintenance

“…3). 77,80,81 An underlying mechanism may be that Slx4 and Rad9 compete for binding to BRCT1-2 of Dpb11, though Slx4 can also associate with BRCT3-4 of Dpb11. 77,79 It appears that BRCT1-2 and BRCT3-4 of Dpb11 can engage Slx4 and the 9-1-1 complex.…”