the three subunits are simultaneously glycosylated in vivo by O-N-acetylglucosamine residues, glycosylation and phosphorylation of the three subunits is dynamic and differs between the subunits, , also depending on the physiological state of the cell, overview
dynamic O-GlcNAcylation of RNA polymerase II. Lipopolysaccharides reduce the O-linked N-acetylglucosamine modification (O-GlcNAcylation) of RNAPII, but enhance the binding of this enzyme to the iNOS promoter. GlcN enhances RNAPII O-linked GlcNAcylation, but inhibits iNOS promoter binding
the two subunits are simultaneously glycosylated by N-O-acetylglucosamine residues in vivo, glycosylation and phosphorylation of the two subunits is dynamic and differs between the subunits, , also depending on the physiological state of the cell, overview
RNAPII C-terminal heptarepeat domain is subject to phosphorylation, e.g. at Ser5 and Ser7, during initiation and elongation of transcription by RNA polymerase II, e.g. by cyclin-dependent kinase 7, CDK7. Phosphorylation of both Ser5 and Ser7 is fully dependent on the cofactor complex Mediator. A subform of Mediator associated with an active RNAPII is critical for preinitiation complex formation and CTD phosphorylation. Free RNAPII that is recruited to templates in the absence of Mediator is not efficiently phosphorylated by CDK7. The Mediator-RNAPII complex independently recruits TFIIB and CDK7 to core promoter regions. CDK7 phosphorylates Ser7 selectively in the context of an intact preinitiation complex, inhibition by roscovitine, molecular mechanisms, overview
RNAPIIis recruited to gene promoters in a hypophosphorylated state, but is phosphorylated at Ser5, Ser7, and Ser2. Its escape from the promoter requires TFIIH-mediated phosphorylation of Ser5, the onset of productive elongation requires P-TEFb, which phosphorylates Ser2 residues of the RNAPII C-terminal domain to produce stable elongation complexes. Absence of Ser 2Pat poised RNAPIIcomplexes is likely to disrupt co-transcriptional RNAmaturation and histone modification to help maintain the silent state, whereas binding and transcription by RNAPII counteract Polycomb-mediated chromatin condensation
the three subunits are simultaneously phosphorylated on serine and threonine residues in vivo, glycosylation and phosphorylation of the three subunits is dynamic and differs between the subunits, , also depending on the physiological state of the cell, overview
the two subunits are simultaneously phosphorylated on serine and threonine residues in vivo, glycosylation and phosphorylation of the three subunits is dynamic and differs between the subunits, also depending on the physiological state of the cell, overview
the yeast Ctk1 kinase associates with elongation complexes and phosphorylates serine 2 in the YSPTSPS repeats of the RNApII large subunit Rpb1 C-terminal domain, a modification that is necessary for efficient recruitment of the Set2 methyltransferase to RNApII within transcribed regions and for coupling transcription to mRNA 3'-end processing, but Ser2 phosphorylation of the Rpb1 CTD does not regulate the 5' transitions. Ctk1 kinase activity is not required for the dissociation of basal transcription factors
in embryonic stem cells, silent developmental regulator genes that are repressed by Polycomb are associated with a form of RNAPII that can elongate through coding regions but that lacks the post-translational modifications that are important for coupling RNA synthesis to co-transcriptional maturation
The activity of basal Pol I factors is regulated by posttranslational modifications, overview, e.g. acetylation is a posttranslational modification that regulates the activity of basal Pol I transcription factors, including UBF and SL1/TIF-IB
several posttranslational modifications of the large subunit of RNA polymerase II, Rpb1, including hydroxylation of Pro1465, nondegradative ubiquitylation of RNA Pol II, and phosphorylation of Ser5. Induction of Rpb1 hydroxylation, phosphorylation, and ubiquitylation requires the presence of the von Hippel-Lindau protein, overview
The activity of basal Pol I factors is regulated by posttranslational modifications, overview, e.g. acetylation is a posttranslational modification that regulates the activity of basal Pol I transcription factors, including UBF and SL1/TIF-IB
several posttranslational modifications of the large subunit of RNA polymerase II, Rpb1, including hydroxylation of Pro1465, nondegradative ubiquitylation of RNA Pol II, and phosphorylation of Ser5. Induction of Rpb1 hydroxylation, phosphorylation, and ubiquitylation requires the presence of the von Hippel-Lindau protein, overview