TY - JOUR
T1 - Effects of cycloheximide on thermotolerance expression, heat shock protein synthesis, and heat shock protein mRNA accumulation in rat fibroblasts
AU - Widelitz, R. B.
AU - Magun, B. E.
AU - Gerner, E. W.
PY - 1986
Y1 - 1986
N2 - A single hyperthermic exposure can render cells transiently resistant to subsequent high temperature stresses. Treatment of rat embryonic fibroblasts with cycloheximide for 6 h after a 20-min interval at 45°C inhibits protein synthesis, including heat shock protein (hsp) synthesis, and results in an accumulation of hsp 70 mRNA, but has no effect on subsequent survival responses to 45°C hyperthemia. hsp 70 mRNA levels decreased within 1 h after removal of cycloheximide but then appeared to stabilize during the next 2 h (3 h after drug removal and 9 h after heat shock). hsp 70 mRNA accumulation could be further increased by a second heat shock at 45°C for 20 min 6 h after the first hyperthermic exposure in cycloheximide-treated cells. Both normal protein and hsp synthesis appeared increased during the 6-h interval after hyperthermia in cultures which received two exposures to 45°C for 20 min compared with those which rceived only one treatment. No increased hsp synthesis was observed in cultures treated with cycloheximide, even though hsp 70 mRNA levels appeared elevated. These data indicate that, although heat shock induces the accumulation of hsp 70 mRNA in both normal and thermotolerant cells, neither general protein synthesis nor hsp synthesis is required during the interval between two hyperthermic stresses for Rat-1 cells to express either thermotolerance (survival resistance) or resistance to heat shock-induced inhibition of protein synthesis.
AB - A single hyperthermic exposure can render cells transiently resistant to subsequent high temperature stresses. Treatment of rat embryonic fibroblasts with cycloheximide for 6 h after a 20-min interval at 45°C inhibits protein synthesis, including heat shock protein (hsp) synthesis, and results in an accumulation of hsp 70 mRNA, but has no effect on subsequent survival responses to 45°C hyperthemia. hsp 70 mRNA levels decreased within 1 h after removal of cycloheximide but then appeared to stabilize during the next 2 h (3 h after drug removal and 9 h after heat shock). hsp 70 mRNA accumulation could be further increased by a second heat shock at 45°C for 20 min 6 h after the first hyperthermic exposure in cycloheximide-treated cells. Both normal protein and hsp synthesis appeared increased during the 6-h interval after hyperthermia in cultures which received two exposures to 45°C for 20 min compared with those which rceived only one treatment. No increased hsp synthesis was observed in cultures treated with cycloheximide, even though hsp 70 mRNA levels appeared elevated. These data indicate that, although heat shock induces the accumulation of hsp 70 mRNA in both normal and thermotolerant cells, neither general protein synthesis nor hsp synthesis is required during the interval between two hyperthermic stresses for Rat-1 cells to express either thermotolerance (survival resistance) or resistance to heat shock-induced inhibition of protein synthesis.
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U2 - 10.1128/MCB.6.4.1088
DO - 10.1128/MCB.6.4.1088
M3 - Article
C2 - 3785158
AN - SCOPUS:0022636161
SN - 0270-7306
VL - 6
SP - 1088
EP - 1094
JO - Molecular and cellular biology
JF - Molecular and cellular biology
IS - 4
ER -