Alternative titles; symbols
HGNC Approved Gene Symbol: SUB1
Cytogenetic location: 5p13.3 Genomic coordinates (GRCh38) : 5:32,585,557-32,604,079 (from NCBI)
Class II genes are transcribed by RNA polymerase II, which participates with the TFIID transcription complex composed of both general factors, including TATA-binding protein (TBP; 600075), as well as gene-specific factors. The latter include TBP-associated factors (TAFs), which interact with the activation domains of various regulatory proteins to enhance transcription (e.g., TAF1; 313650). A second group of positive cofactors includes PC1, PC2, and PC3; they are distinct from TFIID and are present in the so-called upstream stimulatory activity (USA) cell fraction. These factors also have a strong positive influence on transcription. A third group of factors isolated from the USA fraction suppress transcription. Ge and Roeder (1994) described the cloning of an additional human cofactor, designated PC4, that mediates transcriptional activation of class II genes. The protein for PC4 was partially purified and limited amino acid sequence was obtained. That sequence showed similarity to a previously cloned mouse gene (p14). Based on these data, Ge and Roeder (1994) designed PCR primers and the cDNA was subsequently isolated from a HeLa cell cDNA library. A similar strategy was used by Kretzschmar et al. (1994) to clone the identical p15 gene. The 127-amino acid protein was demonstrated to be a single-stranded DNA-binding protein and the recombinant PC4 was shown to function identically to the native protein through its interaction with TAFs.
Downstream core promoter elements (DPE) are regulatory sequences that add diversity to the promoter architecture of RNA polymerase II-transcribed genes. Despite a functional correlation between the presence of TFIID and DPE, Lewis et al. (2005) found that TFIID was insufficient for DPE-specific transcription in HeLa cells. Using a functional transcription assay coupled with conventional biochemistry, they found that protein kinase CK2 (see CSNK2A1; 115440), in conjunction with the coactivator PC4, established DPE-specific transcription.
Ge, H., Roeder, R. G. Purification, cloning, and characterization of a human coactivator, PC4, that mediates transcriptional activation of class II genes. Cell 78: 513-523, 1994. [PubMed: 8062391] [Full Text: https://doi.org/10.1016/0092-8674(94)90428-6]
Kretzschmar, M., Kaiser, K., Lottspeich, F., Meisterernst, M. A novel mediator of class II gene transcription with homology to viral immediate-early transcriptional regulators. Cell 78: 525-534, 1994. [PubMed: 8062392] [Full Text: https://doi.org/10.1016/0092-8674(94)90429-4]
Lewis, B. A., Sims, R. J., III, Lane, W. S., Reinberg, D. Functional characterization of core promoter elements: DPE-specific transcription requires the protein kinase CK2 and the PC4 coactivator. Molec. Cell 18: 471-481, 2005. [PubMed: 15893730] [Full Text: https://doi.org/10.1016/j.molcel.2005.04.005]