Fig. 7.

DYRK1B facilitates EHMT2 recruitment to DSBs. (A) Control (CTR gRNA) or cells transduced with DYRK1B gRNAs (DYRK1B gRNA#1 and DYRK1B gRNA#2) were transiently transfected with the GFP-EHMT2 expression construct. Twenty-four hours posttransfection, cells were microirradiated and time-lapse images were captured to monitor GFP-EHMT2 migration to laser-induced DNA damage tracks. Arrowheads denote sites of laser microirradiation. Quantification is shown and is derived from two independent experiments of at least 10 cells each. (B) Schematic illustration of EHMT2 protein domains and the DYRK1B-enriched EHMT2 phosphopeptide surrounding T346. Note that T346 corresponds to T555 in the long isoform of EHMT2. (C and D) GFP-tagged WT EHMT2 or its phosphomutants (T346A and T346D) were expressed in U2OS cells prior to laser microirradiation and time-lapse imaging experiments as done in A. (E) Working model depicting DYRK1B in orchestrating transcription suppression on DSB-flanking chromatin. DYRK1B accumulates at DSBs in a PARP-dependent manner, and promotes EHMT2 T346 phosphorylation and concentration at DSBs to effect DISC.