Differentiation of mouse embryonal carcinoma cells PCC4 by heat shock and the kinetics of induction of heat shock proteins.

Heat shock to embryonal carcinoma cells PCC4 at 45 degrees C for 30 min resulted in the differentiation of cells although heat shock response was induced on exposure to 42 degrees C for 60 min. Differentiated cells were large and well spread with reduced nuclear/cytoplasmic ratios as compared to undifferentiated cells. Change in cell morphology was associated with the disappearance and appearance of stage specific embryonic antigens 1 and 3 respectively. We also found a change in intracellular pH in PCC4 cells within 30 min of heat shock as measured by the change in fluorescence intensity of a probe incorporated into cells during heat shock.