Temperature adaptation of Drosophila populations. The heat shock proteins system

Abstract

1. 1. The heat shock proteins (hsps) system has been studied in two replicate cage populations (1D, 1C) of Drosophila melanogaster, which were maintained under different environmental conditions (temperature and relative humidity) for approximately 7 yr and exhibited different survival when they were subjected to temperature shock. 2. 2. The kinetics of protein synthesis in ovaries from D and C flies (and their reciprocal hybrids DC and CD) were subjected to heat stress, and the electrophoretic patterns of heat shock proteins (especially of the hsp 70 K), are correlated with the survival of the fly. 3. 3. These results confirm already obtained results using different stocks which were subjected to different type of selection (indirect selection; Stephanou et al., 1982), which represents good evidence for the biological significance of the hsps. 4. 4. The capacity of protein synthesis (and especially of hsp 70 K) following temperature shock is higher in ovaries from D (25°C) or DC flies as compared with those from C (14°C) or CD ones. 5. 5. It is proposed that the regulation of hsps synthesis can be considered as a major target of temperature-induced selection, and an effective molecular mechanism for temperature compensation.