Journal: Nucleic Acids Research
Article Title: PARP1 and PARP2 are dispensable for DNA repair by microhomology-mediated end-joining at double-ended DSBs
doi: 10.1093/nar/gkaf1437
Figure Lengend Snippet: MMEJ is predominantly active in mitosis, when PARP1 is dispensable for DSB repair. ( A ) Experimental timeline for panel (B). Sixteen hours prior to transfection, cells were synchronized in G1 with palbociclib (250 nM), drugs were added 5 h after transfection and flow cytometry was performed 48 h later. A control was performed with the same timeline but without palbociclib synchronization. ( B ) MMEJ quantification using the MMEJ reporter with ISceI or Cas9 cut in asynchronous or G1-synchronized HT1080 cells. Drugs used: olaparib (5 µM), Polθi (ART558, 10 µM), DNA-PKcsi (NU7441, 1 µM). Data represent three independent experiments. ( C ) MMEJ quantification using the reporter with ISceI cut in HT1080 parental cells and indicated isogenic RHNO1 -KO or POLQ- KO clonal lines, ± olaparib 5 µM. Data represent three independent experiments, each the average of three technical replicates. ( D ) Experimental timeline for panel (E). HT1080 cells are arrested in RO3306 (9 µM) for 16 h DMSO (0.1%), olaparib (5 µM), or Polθi (ART558, 10 µM) were added 15 h after RO3306. After 16 h in RO3306, RO3306 was removed and cells were maintained in respective DMSO, olaparib, or Polθi treatment. Cells were irradiated (2 Gy) 40 min after RO3306 release and fixed for micronuclei staining 5 h later. ( E ) Representative images (left) and quantification (right panel) of IF from HT1080 cells from panel (D) in cells 5 h post irradiation compared to no irradiation. Cells were stained for DAPI and the percentage of cells with micronuclei was quantified. Data represent three independent experiments. For each replicate, at least 300 cells were analysed. Statistical analyses for panels (B), (C), and (E): Statistical test, one way ANOVA with multiple comparison correction. ns: nonsignificant, * P <.05, ** P <.01, *** P <.001, **** P <.0001.
Article Snippet: Fibrosarcoma HT1080 cells were purchased from ATCC (CCL-121).
Techniques: Transfection, Flow Cytometry, Control, Irradiation, Staining, Comparison