SECRETED HEAT-SHOCK PROTEINS IN SUNFLOWER SUSPENSION CELL-CULTURES

Sunflower suspension cell cultures were subjected to different heat tr eatments and the electrophoretic patterns of heat-induced endocellular and secreted proteins were analyzed. In response to heat shock (3 h a t 40 degrees C), sunflower cells synthesized new polypeptides and secr eted them into the medium, while the synthesis of other polypeptides w as suppressed. Two major polypeptides of about 50 and 32 kDa were stro ngly induced. The two-dimensional electrophoretic analysis showed that the 32-kDa band is composed of at least four different polypeptides. Western blotting hybridizations of secreted proteins with various lect ins were performed. The 32-kDa band gave a positive signal with concan avalin A.