HEAT-SHOCK-PROTEIN-27 STIMULATES RECOVERY OF RNA AND PROTEIN-SYNTHESIS FOLLOWING A HEAT-SHOCK

Constitutive expression of human hsp27 resulted in a 100-fold increase in survival to a single lethal heat shock in CHO cells without effect ing the development of thermotolerance. A possible mechanism for the t hermoprotective function of hsp27 may be increased recovery of protein synthesis and RNA synthesis following a heat shock. A lethal heat sho ck (44 degrees C, 30 min) results in a 90% reduction in the rate of pr otein synthesis in non-tolerant cells. Control transfected cells recov ered protein synthesis to a pre-heat shock rate 10 h after the heat sh ock; while cell lines that constitutively express human hsp27 recovere d 6 h after the heat shock. Thermotolerant cells had a 50% reduction i n protein synthesis, which recovered within 7 h following the heal sho ck. The same lethal heat shock (44 degrees C, 30 min) reduced RNA synt hesis by 60% in the transfected cell lines, with the controls recoveri ng in 7 h; while the hsp27 expressing cell lines recovered within 5 h. Thermotolerant cells had a 40% reduction in RNA synthesis and were ab le to recover within 4 h. The enhanced ability of hsp27 to facilitate recovery of protein synthesis and RNA synthesis following a heat shock may provide the cell with a survival advantage. (C) 1997 Wiley-iiss, Inc.