Cloning and characterization of SNAP50, a subunit of the snRNA-activating protein complex SNAPc.

摘要: The human RNA polymerase II and III snRNA promoters share a common basal element, the proximal sequence element (PSE), which is recognized by complex we refer to as snRNA-activating protein (SNAPc). Biochemical purifications suggest that SNAPc composed of at least four polypeptides 43, 45, 50 190 kDa, well variable amounts TATA box binding protein, TBP. cDNAs encoding 43 45 kDa subunits, SNAP43 SNAP45, have been isolated, but there no evidence either these subunits contacts DNA. Here report isolation subunit SNAPc, SNAP50. open reading frame predicts 411 amino acid contains two potential zinc finger motifs. Depletions with anti-SNAP50 antibodies inhibit gene transcription in vitro. SNAP50 interacts co-immunoprecipitation experiments, not SNAP45 or UV cross-linking experiments DNA SNAP complex. These results are consistent same core recognizing PSEs promoters, provide an initial view architecture