Expression of Drosophila's 27 kDa heat shock protein into rodent cells confers thermal resistance.

The role of hsp27, one of Drosophila melanogaster's small heat shock proteins, in the process of thermotolerance was investigated. The coding sequence of hsp27 was subcloned downstream of the human hsp27 promoter which has been shown to be constitutively expressed in Chinese hamster O23 cells. Cellular resistance to a thermal stress was measured two days after transfection by a survival assay following a 3.5 h heat treatment at 44 degrees C. Expression of Drosophila hsp27 was shown to confer thermal resistance to O23 cells in a manner which was dependent on the level of expression of this hsp. Immunoblot analysis confirmed that the thermal resistance was related to the expression of Drosophila hsp27 as none of the endogeneous hsps showed an increased level under these conditions.