Analysis of the temperature-dependent temporal pattern of heat-shock-protein synthesis in fish cells

Continuous exposure of Chinook salmon embryo cells to an elevated incubation temperature of 24 degrees C induces the transient expression of a set of heat-shock or stress proteins whereas maintenance of the cells at a higher incubation temperature of 28 degrees C produces a continuous synthesis of these stress proteins. In vitro translation studies suggest that the temperature-dependent temporal pattern of stress-protein synthesis is correlated with the levels of stress-protein mRNA. This was verified using a recombinant-DNA probe complementary to the 70K heat-shock-protein mRNA. A transient increase in the level of the fish heat-shock 70K mRNA was observed in RNA samples isolated from cells continuously exposed at 24 degrees C. However, a constant increase in the level of this specific mRNA was found in RNA preparations obtained from cells maintained at 28 degrees C. Therefore, the temperature-dependent pattern of fish heat-shock-protein synthesis appears to be directly related to the level of heat-shock-protein mRNA.