RNA polymerase II (RNAP II and Pol II) is a multiprotein complex that transcribes DNA into precursors of messenger RNA (mRNA) and most small nuclear RNA (snRNA) and microRNA. It is one of the three RNAP enzymes found in the nucleus of eukaryotic cells. A 550 kDa complex of 12 subunits, RNAP II is the most studied type of RNA polymerase. A wide range of transcription factors are required for it to bind to upstream gene promoters and begin transcription. The eukaryotic core RNA polymerase II was first purified using transcription assays. The purified enzyme has typically 10–12 subunits (12 in humans and yeast) and is incapable of specific promoter recognition.[9] Many subunit-subunit interactions are known. RNA polymerase II holoenzyme is a form of eukaryotic RNA polymerase II that is recruited to the promoters of protein-coding genes in living cells. It consists of RNA polymerase II, a subset of general transcription factors, and regulatory proteins known as SRB proteins. Part of the assembly of the holoenzyme is referred to as the preinitiation complex, because its assembly takes place on the gene promoter before the initiation of transcription. The mediator complex acts as a bridge between RNA polymerase II and the transcription factors. Here you can see a recent structure of RNApol II holoenzyme complex from Sus scrofa determined by CryoEM, and showing the growing synthesized RNA chain from the DNA template (PDB code: 7OL0)
#molecularart ... #immolecular ... #RNApol2 ... #Susscrofa ... #CryoEM ... #holoenzyme ... #complex ... #transcription ... Rendered with @proteinimaging and finished with @corelphotopaint
#molecularart ... #immolecular ... #RNApol2 ... #Susscrofa ... #CryoEM ... #holoenzyme ... #complex ... #transcription ... Rendered with @proteinimaging and finished with @corelphotopaint
