Fig. 6. PARP-1 and PARP-2 are delocalized from the nucleolus upon RNA pol I transcription inhibition. Wide field views of the simultaneous immunodetection of PARP-2 and PARP-1 in wild-type MEFs treated or not (NT, not treated) with 0.05 µg/ml actinomycin D for 2 hours, 50 µg/ml -amanitin for 2 hours, 100 µM DRB for 1 hour, and in one experiment, followed by two washes with PBS and a 1 hour incubation in fresh medium or 10µM camptothecin (CPT) for 30 minutes. Cells were fixed with 1% formaldehyde/0.1% Triton X-100. DNA is stained with DAPI. Co-immunodetection of PARP-2 and B23 was performed in parallel under the same conditions; only the B23 staining is shown in the right panels. Bar, 10 µm.