A HUMAN HOMOLOG OF SACCHAROMYCES-CEREVISIAE SNF2 SWI2 AND DROSOPHILA-BRM GENES POTENTIATES TRANSCRIPTIONAL ACTIVATION BY THE GLUCOCORTICOIDRECEPTOR/

Several of the SNF and SWI genes of Saccharomyces cerevisiae code for proteins believed to assist transcriptional activators by relieving nu cleosome repression. One of these proteins, SNF2/SWI2, has a homologue in Drosophila, a regulator of homeotic genes known as brahma or brm. In this report, we show that a counterpart of SNF2/SWI2 also exists in mice and humans. The human protein, designated hbrm, is a 180 kDa nuc lear factor that can function as a transcriptional activator when fuse d to a heterologous DNA binding domain. The mouse homologue of hbrm is expressed in all mouse organs tested while hbrm was detected in some but not all investigated human cell lines. In cells failing to express the endogenous gene, transfected hbrm co-operates with the glucocorti coid receptor (GR) in transcriptional activation. However, hbrm had no effect on the activity of several other transcription factors, includ ing the homeoprotein HNF-1. The co-operation between hbrm and GR requi red the DNA binding domain of GR and two separated regions of the hbrm protein, including a domain with homology to known helicases.