Effects of heat shock on gene expression and subcellular protein distribution in Chinese hamster ovary cells.

Incubation of Chinese Hamster Ovary (CHO) cells for one hour at 43 degrees C results in several obvious changes in protein distribution and protein synthesis. One major protein of the cytoplasm (molecular weight 45,000 daltions), also present as a minor component in the nucleus, rapidly disappeared while several proteins, especially high molecular weight peptides, were induced by heat shock. Localization of the proteins in the cytoplasm, extra-nucleolar chromatin and nucleolar bodies has been carried out. Different sets of induced proteins appear in each subcellular compartment. Four hours after restoration of the normal temperature, the normal pattern of protein synthesis was observed. The 45,000 dalton protein reappeared first. Relations between structural and functional alterations and changes in protein distribution are suggested.