PathwayStep177 PathwayStep194 PathwayStep195 PathwayStep196 RNA Polymerase III Promoter Opening at Type 3 Promoters Binding of SNAPc, Oct-1, and Staf to Type 3 Promoter Recruitment of RNA Polymerase III to TFIIIB:SNAPc:Type 3 Promoter Complex Binding of TFIIIB to SNAPc:Oct-1:Staf:Type 3 Promoter Complex RNA Polymerase III Transcription Initiation From Type 3 Promoter Authored: Hernandez, N, 2003-09-11 07:42:29 Edited: Joshi-Tope, G, 0000-00-00 00:00:00 Pubmed1535687 Pubmed1868835 Pubmed2853685 Pubmed2905684 Pubmed8336708 Pubmed8339931 Pubmed8979085 Pubmed9705341 Pubmed9776743 Reactome Database ID Release 4376071 Reactome, http://www.reactome.org ReactomeREACT_571 The metazoan-specific type 3 promoters, which are exemplified by the human U6 promoter, recruit a complex variously called the snRNA activating protein complex (SNAPc) (Sadowski et al., 1993), the PSE binding protein (PBP) (Waldschmidt et al., 1991), or the PSE transcription factor (PTF) (Murphy et al., 1992). The complex contains five types of subunits and binds to the PSE. Type 3 promoters also recruit Brf2-TFIIIB through a combination of protein-protein contacts with SNAPc and a direct association of the TBP component of Brf2-TFIIIB with the TATA box. This then allows RNA polymerase III to join the complex.<p>The down stream element (DSE) of type 3 promoters, which enhances transcription from the core promoter, almost invariably contains an octamer sequence and an SPH element (also called NONOCT element)(Cheung et al., 1993; Danzeiser et al., 1993; Kunkel et al., 1996; Myslinski et al., 1992). The octamer sequence recruits the POU domain protein Oct-1 (Herr et al., 1988; Sturm et al., 1988), and the SPH element recruits a zinc finger protein known as Staf or SPH binding factor (SBF), which has been cloned from humans (Myslinski et al., 1998; Rincon et al., 1998).