Fig. 6. Downregulation of B-Myb by RNA interference leads to a defect in chromosome condensation. HEL cells treated with 10^–8 M TPA for 16 hours were subjected to three rounds of transfection with 50 nM of the different siRNAs for 3 hours at intervals of one day. At 2 hours after the final treatment, chromosome spreads were prepared in the presence of hypotonic buffer and stained with DAPI. (A) Control siRNA, (B) siRNA 1, (C) siRNA 2. The upper and lower panels show diploid and polyploid cells, respectively. The arrows indicate fragmented chromosomes.