Fig. 1. Requirement for FADD in PKC/Ras-mediated apoptosis. A, RNA blot of ras transcript levels in Jurkat, Jurkat/ras, Jurkat/Fasm/ras (I4.1) and Jurkat/FADDm/ras (I2.1) cells. Total RNA from these cells was prepared, separated on an agarose gel, and probed with a 32P-labeled ras probe. Equal loading of total RNA was ensured by rehybridization of the blot with a radiolabeled probe for ß-actin. B, DNA fragmentation in Jurkat, Jurkat/Fasm (clones I4.1, E2, and I6.5), Jurkat/FADDm (clones I2.1, E1, and I6.2), or Jurkat cells expressing dn-FADD, in the presence or absence of v-ras, after 48 h of PMA (500 nM) treatment or under normal growth conditions. Control, no treatment ({square}); PMA (500 nM; 48 h), the cells treated with 500 nM of PMA for 48 h (); ras, the cells expressing v-ras under normal growth conditions (); ras + PMA (500 nM; 48 h), the cells expressing v-ras treated with 500 nM PMA for 48 h ({blacksquare}). Bars, SD of eight independent experiments.