title: A map of protein-protein contacts within the small nuclear RNA-activating protein complex SNAPc.
abstract: The nucleation of RNA polymerases I-III transcription complexes is usually directed by distinct multisubunit factors. In the case of the human RNA polymerase II and III small nuclear RNA (snRNA) genes, whose core promoters consist of a proximal sequence element (PSE) and a PSE combined with a TATA box, respectively, the same multisubunit complex is involved in the establishment of RNA polymerase II and III initiation complexes. This factor, the snRNA-activating protein complex or SNAP(c), binds to the PSE of both types of promoters and contains five types of subunits, SNAP190, SNAP50, SNAP45, SNAP43, and SNAP19. SNAP(c) binds cooperatively with both Oct-1, an activator of snRNA promoters, and in the RNA polymerase III snRNA promoters, with TATA-binding protein, which binds to the TATA box located downstream of the PSE. Here we have defined subunit domains required for SNAP(c) subunit-subunit association, and we show that complexes containing little more than the domains mapped here as required for subunit-subunit contacts bind specifically to the PSE. These data provide a detailed map of the subunit-subunit interactions within a multifunctional basal transcription complex.
authors.affiliation: Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, NY 11724, USA.
authors.forename: B
authors.initials: B
authors.lastname: Ma
authors.forename: N
authors.initials: N
authors.lastname: Hernandez
mesh_terms: D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D001665:Binding Sites; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D017433:Protein Structure, Secondary; D021122:Protein Subunits; D011506:Proteins / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000378:metabolism; D020218:Response Elements; D017384:Sequence Deletion; D014157:Transcription Factors / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*
chemical_list: D004268:DNA-Binding Proteins; D046911:Macromolecular Substances; D021122:Protein Subunits; D011506:Proteins; D016601:RNA-Binding Proteins; C093069:SNAPC1 protein, human; C099437:SNAPC2 protein, human; C101746:SNAPC3 protein, human; C116351:SNAPC4 protein, human; C114490:SNAPC5 protein, human; D014157:Transcription Factors; D004247:DNA