Figure 3.

FTI induces chromatin condensation and DNA fragmentation. (A) Chromatin condensation and segregation. KNRK cells were plated at a density of 5 × 10⁴ cells/well in a four-well chamber slide (LAB-TEK) in 10% FCS medium. After 24 h, the medium was changed to 0.1% FCS and the cells were treated with DMSO (Control) or with 20 μM SCH56582 (+ FTI). After 24 h, cells were washed and fixed in 4% paraformaldehyde and stained with DAPI to check chromatin condensation and segregation as described in Materials and Methods. At least three separate experiments were carried out with results similar to those shown here. (B) Internucleosomal DNA fragmentation. KNRK and Spon 8 cells were seeded at 5 × 10⁵ cells/60-mm dish in 10% FCS medium. After 24 h, the medium was changed to 0.1% FCS medium supplemented with DMSO (lanes 1 and 6), 20 μM SCH56582 (lanes 3 and 7), 20 μM PD98059 (lane 2), or 20 μM SCH56582 plus 50 μM Z-DEVD-fmk (lane 4). After 24 h, genomic DNA was prepared and analyzed with a 1.7% agarose gel as described in Materials and Methods. Lane 5 shows DNA size markers (1 kb DNA ladder, GIBCO/BRL).