Updating the rna polymerase ctd code
Recent studies show that the two remaining potential phosphorylation sites, tyrosine-1 and threonine-4, are phosphorylated as well and contribute to the previously proposed "CTD code".
With the impairment of binding of CTD interacting factors, these novel phosphorylation marks add an accessory layer of regulation to the RNAP II transcription cycle.
The Pol2 CTD consists of tandemly repeated heptapeptides of consensus sequence Y GTase (Pce1) bound to Ser5-phosphorylated Pol2 CTD ligands illuminated how eukarya take divergent structural routes to achieve GTase•CTD interaction.
These three cellular GTases are structurally homologous enzymes composed of two domains: an N-terminal nucleotidyltransferase (NTase) module containing the guanylate binding pocket; and a C-terminal OB fold module.
Our analysis of fission yeast Pce1 mutations that disrupt the Pol2 CTD interface shows that at least one of the two Ser5-PO binding sites is required for cell viability, and that each site is important for cell growth at 37˚C.
cells had increased levels of ferric reductase activity and were hypersensitive to phleomycin, indicative of elevated intracellular iron.
We identified CTD letters Thr4 and Ser7 as novel components of the fission yeast phosphate homeostatic response, on which the ) under phosphate-replete conditions.
The RNA triphosphatase (TPase) components of the mammalian and budding yeast capping apparatus are recruited passively to the Pol2 CTD, by virtue of their physical association with the GTase: in has a distinctive strategy for targeting cap formation to Pol2 transcripts, whereby the TPase (Pct1) and GTase (Pce1) enzymes are not associated physically, but instead bind independently to the Ser5-phosphorylated Pol2 CTD Capping enzymes can also access nascent Pol2 transcripts via physical interactions with transcription elongation factor Spt5.
Spt5 is a large polypeptide, composed of multiple domain modules, that associates with the Pol2 transcription complex shortly after initiation and can exert negative and positive effects on transcription elongation.