Protein synthesis is required for stabilization of hsp70 mRNA upon exposure to both hydrostatic pressurization and elevated temperature

We have recently described that in chondrocytic cells high hydrostatic pres sure (HP) causes a heat shock response via mRNA stabilization without a tra nscriptional activation of the hsp70 gene. In this study, we investigated w hether this exceptional regulatory mechanism occurs more generally in diffe rent types of cells. Indeed, hsp70 mRNA and protein accumulated in HeLa, Ha Cat and MG-63 cells under 30 MPa HP, without DNA-binding of heat shock tran scription factor 1 (HSF1) to the heat shock element of the hsp70 gene or fo rmation of nuclear HSF1 granules, revealing a lack of transcriptional activ ation. Moreover, we observed that protein synthesis is needed for mRNA stab ilization. Thus, high HP offers a model to study the mechanisms of hsp70 mR NA stabilization without HSF1-mediated induction of the heat shock gene res ponse. (C) 2000 Federation of European Biochemical Societies. Published by Elsevier Science B.V. All rights reserved.