EXPRESSION OF DIFFERENT FORMS OF THE HEAT-SHOCK FACTOR DURING THE LIFE-CYCLE OF THE PARASITIC HELMINTH SCHISTOSOMA-MANSONI

HSE-HSF complexes from different stages of the life cycle of schistoso me were analyzed by pore exclusion electrophoresis (estimates the size of the native DNA-protein complex), and by U.V.-cross-linking followe d by SDS-PAGE (estimates the size of the monomeric heat shock factor, HSF). The apparent M(r) values of the native and monomeric HSE-HSF com plexes from schistosomula were 80 000 and 60 000, respectively. In adu lt worms M(r) values were 70 000 for the native HSE-HSF complex, 60000 and 80 000 for the monomeric form. These findings indicate that: (1) schistosome express two (maybe three) forms of HSF, (2) different form s of HSF are expressed at different developmental stages. The finding that the native HSE-HSF complex and the monomeric HSF are of a similar size indicates that the complex contains a single HSF, or that the co mplex is a labile oligomer of HSF that decomposes into monomers during electrophoresis in a nondenaturing gel.