SWR1 and INO80 Chromatin Remodelers Contribute to DNA Double-Strand Break Perinuclear Anchorage Site Choice

Abstract

Persistent DNA double-strand breaks (DSBs) are recruited to the nuclear periphery in budding yeast. Both the Nup84 pore subcomplex and Mps3, an inner nuclear membrane (INM) SUN domain protein, have been implicated in DSB binding. It was unclear what, if anything, distinguishes the two potential sites of repair. Here, we characterize and distinguish the two binding sites. First, DSB-pore interaction occurs independently of cell-cycle phase and requires neither the chromatin remodeler INO80 nor recombinase Rad51 activity. In contrast, Mps3 binding is S and G2 phase specific and requires both factors. SWR1-dependent incorporation of Htz1 (H2A.Z) is necessary for break relocation to either site in both G1- and S-phase cells. Importantly, functional assays indicate that mutations in the two sites have additive repair defects, arguing that the two perinuclear anchorage sites define distinct survival pathways.

Histone chaperone Anp32e removes H2A.Z from DNA double-strand breaks and promotes nucleosome reorganization and DNA repair

“…In yeast, persistent DSBs contain H2A.Z and are relocated to the nuclear membrane by a mechanism requiring H2A.Z-remodeling ATPases (49,50). Further, DSBs tethered to the nuclear lamina can be repaired by the alt-NHEJ pathway (51).…”

Perinuclear tethers license telomeric DSBs for a broad kinesin- and NPC-dependent DNA repair process

“…For example, the DNA damage response mediator Rad9 (53BP1 in mammals) and Swr1-dependent Htz1 (also known as H2A.Z) incorporation were previously reported to promote DSB mobility 15 . Indeed, we found that subtelomeric DSB repair was greatly dependent on Rad9 (Fig.…”

“…4e,f). DSBs relocating closer to the nuclear envelope often exhibit increased physical interactions with the Mps3 inner nuclear membrane protein 13,15 . Indeed, anti-Mps3 ChIP analysis showed that subtelomeric DSB-Mps3 interaction levels are increased in cells lacking Lrs4 or Cik1 ( Fig.…”

“…In yeast, these locations are the nuclear pore subcomplex Nup84 (composed of seven entities, including Nup84 and Nup145) as well as the Mps3 inner nuclear membrane protein [12][13][14][15] . In fact, DSBs in cells without clear donor DNA sites for repair relocate at least transiently to Nup84 or Mps3 proteins [12][13][14][15] .…”

Chromatin Tagging Systems Contribute to Live Imaging Analyses for Chromatin Dynamics

“…To observe the chromatin dynamics around the double strand break (DSB), lacO/LacI-EGFP was combined with a DSB induction system using an endonuclease, the I-SceI system, in mouse NIH2/4 cells and S. cerevisiae (Soutoglou et al 2007, Dion et al 2012, Mine-Hattab and Rothstein 2012. They showed that the chromatin mobility around DSB was higher than the control and the chromatin around DSB moved to the subnuclear region near the T. Hirakawa and S. Matsunaga Cytologia 81(2) nuclear envelope (Horigome et al 2014). Moreover, chromosome translocation was monitored by the combination system in mouse NIH3T3 cells (Roukos et al 2013).…”