SNAP19 mediates the assembly of a functional core promoter complex (SNAP(c)) shared by RNA polymerases II and III

Abstract

The basal transcription factor SNAP(c) binds to the PSE, a core element in the RNA polymerase II and III human snRNA promoters. SNAP(c) contains at least four subunits, but it has not been possible to assemble a fully defined recombinant SNAP(c). Here we reconstitute SNAP(c) from five recombinant subunits, SNAP43, SNAP45, SNAP50, SNAP190, and a newly identified subunit, SNAP19. This recombinant complex binds specifically to the PSE and directs both RNA polymerase II and III snRNA gene transcription. Thus, the same core SNAP(c) nucleates the assembly of two classes of initiation complexes.