INDUCTION OF THERMOTOLERANCE IN T-CELLS PROTECTS NUCLEAR-DNA TOPOISOMERASE-I FROM HEAT-STRESS

In this study, we have demonstrated that topoisomerase I DNA relaxing activity i protected against a severe heat shock in T cells made thermotolerant by a prior modes heat treatment. However, following a severe heat-shock challenge and incubation a 37°C, topoisomerase activity in the control population eventually returned to level similar to those detected in thermotolerant cells. This recovery of topoisomeras activity appears to result from the renaturation of heat-inactivated enzyme rather tha from synthesis of new protein because the rate of recovery of catalytic activity was no inhibited by the presence of the protein synthesis inhibitor, cycloheximide. © 1992 Academic Press, Inc.