HEAT-INDUCED CHANGES IN NUCLEAR-ASSOCIATED PROTEINS IN NORMAL AND THERMOTOLERANT HELA-CELLS

In the present study we used one-dimensional 7-10% gradient SDS polyac rylamide gels to resolve the proteins associated with nuclei isolated from normal and heat-shocked cells. By analyzing the relative optical density of 27-30 polypeptide bands as a function of the duration of th e heat shock or the time of incubation after heating, we were able to observe the following regarding heat-induced alterations in nuclear pr otein binding. Various proteins show an increased nuclear association in terms of their nuclear protein content, but the kinetics of this as sociation is not identical for individual proteins. Moreover, the chan ges in these associations are differentially affected in nuclei from t hermotolerant cells. This type of analysis demonstrates the possibilit y that the cellular effects of hyperthermia could be correlated with t he altered binding and/or increased presence of specific proteins asso ciated with the nucleus in heated cells.