Nuclear proteins in Drosophila melanogaster cells after heat shock and their binding to homologous DNA

Abstract
After 5 minutes heat shock at 37°C Drosophila melanogaster Kc-cell nuclear proteins were extracted with 0.4M NaCl and compared by SDS gel electrophoresis with extracts from cells grown at 25°C. Two proteins (39 000 and 46 000) were only found in heat shock nuclei. Reconstitution with total Drosophila DNA or a DNA fragment from the heat inducible locus 87A/C covalently coupled to sepharose was performed. In the presence of calf thymus competitor DNA these proteins and also others of lower molecular weight showed preferential binding to the homologous DNA.