Our group has continued studies of chromatin structure and the regulation of heat shock gene expression, with emphasis on the structure and function of the heat shock transcription factor (HSF) and on the remodeling of the heat shock gene promoter in chromatin. Yeast two-hybrid screens have identified several interacting proteins for Drosophila HSF. These proteins are currently being characterized and tested for possible regulatory effects on HSF by molecular and cellular assays. The cloning of the largest subunit for the ATP-dependent nucleosome remodeling factor (NURF) has been completed. This subunit was found to be encoded by a very large ORF predicting a novel, 301 kD polypeptide containing a bromodomain and three PHD fingers. We recently succeeeded in reconstructing a full length cDNA for the 301K ORF. Currently we are characterizing this novel protein and attempting to reconstitute NURF activity from all four subunits by co-expression from baculovirus expression vectors to determine the minimal components necessary for the nucleosome remodeling activity of NURF. - Chromosome, Drosophila, Gene, Heat Shock, Nucleosome, Transcription,