The interaction of the heat shock factor (HSF) with the heat shock element (HSE) was determined by a non-radioactive electrophoretic mobility shift assay, in order to analyze HSF regulation in Neurospora crassa. HSF binds to HSE under normal, non-stress conditions and is thus constitutively trimerized. Upon heat shock, the HSF-HSE complex shows a retarded mobility. This was also observed in Saccharomyces cerevisiae, where this mobility shift was shown to be due to HSF phosphorylation [Sorger and Pelham (1988) Cell 54, 855-864]. In N. crassa, HSE-dependent electrophoretic mobility shift is temperature- and time-dependent. Under normal growth conditions, the HSF is located in the cytoplasm as well as in the nucleus. In germinating conidia the HSF shows a retarded mobility typical for heat shock even at normal growth temperatures. No HSF-dependent mobility shift was detectable in aerial hyphae. Copyright (C) 2000 Federation of European Microbiological Societies.
Meyer, U., Monnerjahn, C., Techel, D., & Rensing, L. (2000). Interaction of the Neurospora crassa heat shock factor with the heat shock element during heat shock and different developmental stages. FEMS Microbiology Letters, 185(2), 255–261. https://doi.org/10.1016/S0378-1097(00)00105-1