Purification and characterization of a human factor that assembles and remodels chromatin

We have previously reported the isolation and characterization of a nucleos ome remodeling and spacing factor, RSF. One of the RSF subunits is hSNF2h, a SNF2 homologue. Here we set out to isolate and characterize other hSNF2h- containing complexes. We have identified a novel hSNF2h complex that facili tates ATP-dependent chromatin assembly with the histone chaperone NAP-1. Th e complex possesses ATPase activity that is DNA-dependent and nucleosome-st imulated. This complex is capable of facilitating ATP-dependent nucleosome remodeling and transcription initiation from chromatin templates. In additi on to hSNF2h, this complex also contains a 190-kDa protein encoded by the B AZ1A gene. Since both subunits are homologues of the Drosophila ACF complex (ATP-utilizing chromatin assembly and remodeling factor), we have named th is factor human ACF or hACF.