Quantitative analysis of the heat shock response of Saccharomyces cerevisiae

M J Miller, N H Xuong, E P Geiduschek
1982 Journal of Bacteriology  
Transient protein synthesis in Saccharomyces cerevisiae, after shift from 21-23°C to 37°C, was quantitatively analyzed. Pulse-labeled proteins were separated by two-dimensional gel electrophoresis, and autoradiograms of the gels were analyzed by a recently described method involving a computer-coupled film scanning system. In this way, the rate of incorporation of L-[ S]methionine into approximately 500 proteins was followed. The synthesis of more than 80 of these proteins was transiently
more » ... s transiently induced at 37°C, with about 20 being classified as major heat shock proteins (defined as those whose rate of labeling was increased at least eightfold at some time during the response). The synthesis of more than 300 of the proteins was transiently repressed at 37°C, and several general temporal patterns of repression could be distinguished. The influence of temperature-sensitive mutations affecting RNA synthesis and transport on the heat shock response was also examined. A protein whose induction in response to heat shock has a posttranscriptional component could be identified. As previously pointed out, the heat shock repression of certain proteins is so rapid that it also must involve posttranscriptional effects. The heat shock response appears to be universal. First discovered in insects (35), it is manifested, at the cellular level, in animals (16), plants (18), fungi (28, 30) , and other higher protists (e.g., 9, 24, 43, 47) and bacteria (21, 46; for reviews, see references 3 and 34). The cellular response to a temperature up-shift involves the transient induction of synthesis of a characteristic set of proteins and the transient repression of synthesis of many (16, 21) or almost all (22, 40) others. The response involves transcriptional (4, 13, 28, 32, 37) as well as post-transcriptional (31) mechanisms (the latter have been analyzed in some detail in connection with the response in Drosophila spp. [20, 38] ) and also (post-translational) modification of certain proteins (11, 24a, 44). At least a part of one of the heat shock proteins is very highly conserved in evolution. Antibody to a chicken heat shockinduced 76-kilodalton protein (16) cross-reacts with heat shock-induced proteins from Dictylostelium discoideum (17; W. F. Loomis, personal communication) and yeasts (17; W. F. Loomis and M. J. Miller, unpublished data) of comparable molecular weights. At the functional level, the heat shock response appears to protect cells from killing at high temperatures (24, 26). t Present address:
doi:10.1128/jb.151.1.311-327.1982 fatcat:6srgpjwcqze37byk5l6wck3a7e