Heat-resistant variants of Chinese hamster fibroblasts altered in expression of heat shock protein.
Heat-resistant variants of the Chinese hamster HA-1 line have been isolated after repeated heat treatments. The heat-resistant phenotype has been stable for over 70 passages. One of the members of the 70-kDa heat shock protein family was found to be synthesized at greater levels in the heat-resistant variants under normal growth conditions. Mild heat treatment of the variant lines induced a transient thermotolerance that was accompanied by additional increase in the synthesis of the 70-kDa heat shock proteins. Cell-free translation of total cellular RNA revealed greater amounts of 70-kDa heat shock protein mRNA in both control and heated variant cells. The greater levels of 70-kDa heat shock protein synthesized in the variant cells presumably are a reflection of altered levels of its messenger mRNA. In addition, we found that translational control plays a role in the elevated expression of heat shock proteins in heat-shocked HA-1 cells and their heat-resistant variants. The association of the heat-resistant phenotype with increased levels of a 70-kDa heat shock protein suggests strongly that this gene product plays a role in protecting cells from damage inflicted by elevated temperatures.
D000818:Animals; D002460:Cell Line; D006224:Cricetinae; D003412:Cricetulus; D005260:Female; D005786:Gene Expression Regulation; D006360:Heat-Shock Proteins / Q000235:genetics*; D007526:Isoelectric Point; D008970:Molecular Weight; D009154:Mutation; D010053:Ovary; D012333:RNA, Messenger / Q000235:genetics
D006360:Heat-Shock Proteins; D012333:RNA, Messenger