Updated project metadata. We performed multilevel proteomics to identify mono-ADPr readers. Pulldowns using ADPribosylated peptides and nucleosomes, analysis of the chromatin proteome using targeted modulations of the ADPr system (H2O2 treatment, ARH3 KO, HPF1 KO). We reveal multiple mono-ADPr readers, including RNF114, a ubiquitin ligase recruited to DNA lesions through a zinc finger domain.