Asymmetrical repartition of chromosome 1s on multipolar spindle of endomitotic megakaryocytes.

Double staining obtained by PRINS and immunofluorescence procedure, as reported in Figure 1, in endomitosis 4N to 8N (A), 8N to 16N (B), and 16N to 32N (C). Centromeres of chromosome 1s (green dots) are asymmetrically distributed among the different spindle poles, as no green dot is associated with some asters. Bar, 5 μm. (D) Asynchronous separation of sister chromatids in a 4N to 8N endomitosis. Additional DNA staining (in blue) was performed: chromosomes have congressed to a complex metaphase plate typical of the metaphase/anaphase transition. The white arrow shows the single chromosome 1 whose chromatids have already separated (2 dots). Panel E corresponds to an interphase megakaryocyte with positive vWF staining (in green): 8 chromosomes (red) are unevenly labeled by FISH (distributed between the 4 lobes of the nucleus [in blue]).