[Effect of actinomycin D, cycloheximide, puromycin and mitomycin C on the biosynthesis of heat shock proteins in the nuclear matrix of Chinese hamster fibroblasts].

The thermal shock proteins with molecular mass of 86 kD and pI 5.5 as well as of 70 kD and pI 5.2-5.4 were isolated by means of two-dimensional electrophoresis in polyacrylamide gel from nuclear matrix of chinese hamster fibroblasts after heating of the animals. Incorporation of 35S-methionine into the thermal shock proteins was completely inhibited by actinomycin D (2 micrograms/ml), if the antibiotic was added into the cell incubation medium before heating, while the incorporation of methionine was decreased only slightly when the antibiotic was added after heating of the cells. Thus, biosynthesis of mRNA of the thermal shock proteins of 86 and 70 kD in nuclear matrix was induced by means of an increase in temperature during the incubation of the cells. Biosynthesis of the thermal shock proteins in nuclear matrix was distinctly inhibited by cycloheximide (1 microgram/ml) and was not practically inhibited by puromycin (60 micrograms/ml).