A bridging helix emanates from RPB1 and crosses the cleft near the catalytic site and is thought to promote translocation of Pol II by acting as a ratchet that moves the RNA-DNA hybrid through the active site by switching from straight to bent conformations at each step of nucleotide addition. During transcription elongation, Pol II moves on the template as the transcript elongates. RNA Pol II CTD phosphorylation and interaction with CE during HIV infection. The 5' transcribed region of the U2 sn RNA gene is largely single-stranded during interphase and metaphase (Pavelitz et al.2008) and chromatin within the transcribed region is cleared of nucleosomes (O'Reilly et al. Transcriptional activation of the RNA polymerase II transcribed sn RNA genes begins with binding of transcription factors to the distal sequence element (DSE) of the promoter (reviewed in Hernandez 2001, Egloff et al. The factors, which include POU2F1 (Oct-1), POU2F2 (Oct-2), ZNF143 (Staf) and Sp1, promote binding of the SNAPc complex (also known as PTF and PBP) to the PSE.SNAPc helps clear the gene of nucleosomes (O'Reilly et al.2014) and recruits initiation factors (TFIIA, TFIIB, TFIIE, TFIIF, and sn TAFc: TBP) which recruit RNA polymerase II.RPB1 is part of the core element with the central large cleft, the clamp element that moves to open and close the cleft and the jaws that are thought to grab the incoming DNA template.
It is composed of mobile elements that move relative to each other.
The process of introducing a phosphate group on to an amino acid residue in the C-terminal domain of RNA polymerase II.
Typically, this occurs during the transcription cycle and results in production of an RNA polymerase II enzyme where the carboxy-terminal domain (CTD) of the largest subunit is extensively phosphorylated, often referred to as hyperphosphorylated or the II(0) form.
Transcription of the U1 and U2 genes has been most extensively studied and the other sn RNA genes as well as other genes with similar promoter structures, for example the SNORD13 gene, are inferred to be transcribed by similar reactions.
The sn RNA genes transcribed by RNA polymerase II are distinguished from m RNA-encoding genes by the presence of a proximal sequence element (PSE) rather than a TATA box and the presence of the Integrator complex rather than the Mediator complex (reviewed in Egloff et al. The sn RNA genes are among the most rapidly transcribed genes in the genome.