text: By reporter gene analysis following transient transfections with various plasmids expressing a dominant negative mutant form of Cdc42, Rac1 or RhoA, << C2-ceramide >>-induced [[ SRE ]] activation was shown to be selectively repressed by pEXV-RacN17 encoding a dominant negative mutant of Rac1, suggesting that Rac activity is essential for the signalling cascade of ceramide to the nucleus.