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Induction of Heat-Shock Protein Synthesis in Teleost Hepatocytes: Effects of Acclimation Temperature

1987; University of Chicago Press; Volume: 60; Issue: 2 Linguagem: Inglês

10.1086/physzool.60.2.30158653

1937-4267

Michael Koban, Glenn C. Graham, C. Ladd Prosser,

thermodynamics and calorimetric analyses

Exposure of organisms to high temperatures characteristically induces the rapid expression of a set of heat-shock genes. We hypothesized that acclimation temperature may alter the threshold temperatures for initiation of heat-shock protein (hsp) synthesis and for sustaining maximal rates of hsp synthesis. Hepatocytes were prepared from channel catfish Ictalurus punctatus acclimated to 7, 15, and 25 C. The cells were incubated at temperatures of 15, 25, 30, 32.5, 35, 37.5, and 40 C, and newly synthesized proteins were labeled with 35S-methionine and resolved by gel electrophoresis. The temperature for induction of hsp synthesis was not altered by acclimation of the fish. Threshold temperature for initiation of synthesis was 32.5 C for fish from each acclimation temperature. The temperature for maximum synthesis of hsps was 37.5 C for 7 C fish, and it was 40 C for 25 C fish. It is concluded that the heat-shock response of catfish hepatocytes is fixed within a narrow range of a few degrees above and below 37.5 C and that the heat-shock response is under genetic rather than environmental control.