By means of immunofluorescence and immunoelectron microscopy we have studied the fate
of different nucleolar components during the apoptotic process in camptothecin‐treated
HL60 cells. We have found that RNA polymerase I disappeared while UBF was associated
with previously described fibrogranular threaded bodies. In contrast, fibrillarin,
C23/nucleolin, and B23/nucleophosmin remained detectable in granular material present
amid micronuclei of late apoptotic cells. Double immunolabeling experiments showed …

Behavior of nucleolar proteins during the course of apoptosis in camptothecin-treated HL-60
cells. …