pfam15497: SNAPC5 (This model is not part of the current CDD release)
snRNA-activating protein complex subunit 19, SNAPc subunit 19
SNAPc19 is a family of proteins found in eukaryotes. It is one of the five core components of the snRNA-activating protein complex or SNAPc that helps direct the nucleation of RNA polymerases II and III. The core RNA polymerase II snRNA promoters consist of a single essential element, the proximal sequence element (PSE), whereas the core RNA polymerase III snRNA promoters consist of both a PSE and a TATA box. The SNAPc binds to the PSE of both of these. SNAPc recognises the PSE sequence common to all human snRNA genes, irrespective of polymerase specificity. SNAPc is also known as the PSE transcription factor (PTF) or PSE-binding protein (PBP). The human SNAP19 and SNAP45 subunits are dispensable for transcription in vitro and are not as widely conserved as the other three, SNAP190, SNAP43 and SNAP50, suggesting that these vertebrate-specific SNAPc subunits may have adapted specialised regulatory roles for snRNA gene transcription.
Jiyao W et al.(2023). "The conserved domain database in 2023.",