Fig. 10: Loss of CHD6 reduces cellular base excision repair capacity to resolve apurinic/apyrimidinic (AP) sites, leading to AP site accumulation within genomic DNA.
Source data are provided as a Source Data file. Panel a Wildtype and CHD6-deleted cells were analyzed by fluorescence multiplex host cell reactivation (as in refs. 69,70,71) using reporter plasmids that monitor resolution of the indicated base excision repair substrates. Bar graph data are geometric means ± CI95%; n = 8. 2-way ANOVAs followed by Tukey post hoc tests were carried out between WT and ΔCHD6, with ns = not significant (p > 0.05), and * representing p = 0.0198 for abasic site and p = 0.0197 for UV substrate. Panel b Workflow for the ELISA assay monitoring apurinic/apyrimidinic (AP) sites present within genomic DNA; figure was created using Biorender (https://BioRender.com/y64d242) and Microsoft PowerPoint. Panel c Wildtype and CHD6 cells were treated ± 0.04% (v/v) MMS for 1 h and either harvested immediately (0 h) or placed into fresh media for 3 h and allowed to recover, before being analyzed as in (b). Data are represented as 5–95 percentile box and whisker plots for n = 4. Black dots in middle of plot represent arithmetic means, centre lines represent medians, and + % values represent relative increase in AP sites per 105 bp in CHD6-deleted cells relative to wildtype. 2-way ANOVAs followed by Tukey post hoc tests were carried out. ns = not significant (p > 0.05),****p < 0.0001. Panel d A composite structural prediction of the arrangement of the CHD6 functional domains in relation to a mononucleosome with linker DNA (light grey), with CHD6 tandem chromodomains shown in purple, the ATPase-Helicase motor domain in blue, and the DBD1 (SWISS-MODEL) in green and the nucleosome template in grey (PDB ID 5O9G). Panel e A model for the molecular circumstances leading to PARPi-induced synthetic lethality with CHD6 loss; this figure was created using Biorender (https://BioRender.com/j29p818) and Microsoft PowerPoint.
