Abstract
Neurospora crassa cells, grown at 28.degree. C for 14 h and heat shocked at 48.degree. C for 45 min, showed the synthesis of 11 heat-shock proteins (nHSPs) in one-dimensional electrophoretic profiles. Treatment with sodium arsenite induced the synthesis of two heat-shock proteins, nHSP70 and nHSP80, and a third, arsenite-specific protein, not induced by hyperthermia. Exposure to 0.5 or 1.0 mM H2O2 led to the induction of two of the heat-inducible nHSP70 family polypeptides. Sodium selenite, used in concert with H2O2, and arsenite were observed to modulate that heat-shock response. In addition, H2O2, menadione, and the glutathione depleters diamide and diethyl maleate promoted the synthesis of another protein, designated oxidative stress-responsive protein (OSP). A DNA-binding protein, specific for Neurospora DNA, was also demonstrated in extracts of heat-shocked cells.