Updating the rna polymerase ctd
Rpb1, the largest subunit of RNA Pol II, contains a highly flexible structure at its C terminus, the carboxy-terminal domain (CTD).
The CTD is unique in RNA Pol II and possesses multiple tandemly repeated heptapeptides with the consensus sequence YSPTSPS.
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.
The 5' transcribed region of the U2 sn RNA gene is largely single-stranded during interphase and metaphase (Pavelitz et al.
Serine 5 is phosphorylated (Ser5P) by transcription factor IIH (TFIIH)-associated kinase, and it remains phosphorylated while RNA Pol II transcribes the first few hundred nucleotides of genes.
Ser5P serves as an acceptor site for RNA triphosphatase and guanylyltransferase, both of which are involved in the capping reaction (5).
This structure is essential for regulating different steps of gene expression, from transcription initiation to elongation and termination (1–3).