Response of high mobility group proteins of human kidney T1 and murine L 929 cell lines to heat shock

High mobility group (HMG) proteins in human kidney T1 and murine L 929 cells have been investigated after exposure to heat shock at 41 degrees C and their influence on the organizational change of chromatin under heat shock condition has been examined. Results reveal that the two cell lines show differential response of the HMG proteins 1 & 2 and 14 & 17 to heat shock. Neither T1 nor L 929 cells show significant differences in response to heat shock with respect to the binding affinities of HMG proteins 1 & 2 or 14 & 17 to DNA, as revealed by DNase I sensitivity and chromatin reconstitution assays. Furthermore, the HMG proteins of both the non-heat shocked and the heat shocked T1 and L 929 cells can recover their chromatin activity following reconstitution. These findings suggest that although the HMG proteins might undergo some change in response to heat shock, their inherent potential of reassociation with DNA is still retained.