Transient acquired thermotolerance in Drosophila, correlated with rapid degradation of Hsp70 during recovery.
Acquired thermotolerance, measured either as increased cell viability following a lethal heat shock or by translational thermotolerance, appears rapidly following a 'priming' heat treatment, but also decays rapidly. 4 hours after priming heating thermotolerance is reduced by > 50% and by 9 hours it is virtually undetectable. Heat-shock protein 70 (Hsp70) turns over with a half-life of approximately 2 hours, and the decline in its intracellular abundance parallels the loss of acquired thermotolerance. Continuous heat shock extends the half-life of Hsp70 to approximately 7 hours. When Hsp70 is expressed at normal temperature using a metallothionein promoter, only partial acquired translational thermotolerance results. The results suggest that acquired thermotolerance is tightly regulated in Drosophila and partly, but not wholly, determined by post-translational regulation of Hsp70 levels.
Li
D
D
University of Southern California School of Pharmacy, Department of Molecular Pharmacology and Toxicology, Los Angeles 90033, USA.
Duncan
R F
RF
D000222:Adaptation, Physiological; D000818:Animals; D002470:Cell Survival; D002478:Cells, Cultured; D002499:Centrifugation, Density Gradient; D004330:Drosophila / Q000378:metabolism*; D015180:Electrophoresis, Gel, Two-Dimensional; D015870:Gene Expression / Q000235:genetics; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism*; D006207:Half-Life; D006358:Hot Temperature; D015151:Immunoblotting; D007700:Kinetics; D008668:Metallothionein / Q000235:genetics / Q000378:metabolism; D011132:Polyribosomes / Q000378:metabolism; D014176:Protein Biosynthesis; D012270:Ribosomes / Q000378:metabolism
D018840:HSP70 Heat-Shock Proteins; D008668:Metallothionein