“…Such mechanisms help ensure that remodelers are only active where and when needed. While the mechanisms through which the Chd1 and ISWI remodelers are regulated by nucleosomes have been explored (Clapier and Cairns, 2012;Hauk et al, 2010;Ludwigsen et al, 2017;Yan et al, 2016), less is known about how DNA damage triggers the activity of remodelers such as the PARP1-dependent ALC1 (Ahel et al, 2009;Gottschalk et al, 2012;, which massively decompacts chromatin upon DNA damage (Movie S1; Sellou et al, 2016). Considering ALC1's validated roles as an oncogene (ALC1 is amplified in several cancers and promotes metastases, proliferation, and pluripotency; Chen et al, 2010;Jiang et al, 2015;Kulkarni et al, 2013;Ma et al, 2008), understanding how PAR triggers ALC1 activity would advance our molecular understanding of how DNA damage impacts our genome, shed light on how a NAD + metabolite and nucleic acid triggers the activation of an oncogene, and reveal approaches that might allow us to target ALC1 therapeutically.…”