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Function of RNA polymerase II (transcription). Green: newly synthesized RNA strand by enzyme. 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. [1] [2] It is one of the three RNAP enzymes found in the nucleus of ...
RNA polymerase II (also called RNAP II and Pol II) is an enzyme found in eukaryotic cells. It catalyzes the transcription of DNA to synthesize precursors of mRNA and most snRNA and microRNA . [ 3 ] [ 4 ] In humans, RNAP II consists of seventeen protein molecules (gene products encoded by POLR2A-L, where the proteins synthesized from POLR2C ...
Transcription preinitiation complex, represented by the central cluster of proteins, causes RNA polymerase to bind to target DNA site. The PIC is able to bind both the promoter sequence near the gene to be transcribed and an enhancer sequence in a different part of the genome, allowing enhancer sequences to regulate a gene distant from it.
RNA Polymerase II Transcription: the process of transcript elongation facilitated by disassembly of nucleosomes. RNAP from T. aquaticus pictured during elongation. Portions of the enzyme were made transparent so as to make the path of RNA and DNA more clear. The magnesium ion (yellow) is located at the enzyme active site.
The positive transcription elongation factor, P-TEFb, is a multiprotein complex that plays an essential role in the regulation of transcription by RNA polymerase II (Pol II) in eukaryotes. [1] Immediately following initiation Pol II becomes trapped in promoter proximal paused positions on the majority of human genes (Figure 1).
P-TEFb phosphorylates the second residue (Ser-2) of the CTD repeats (YSPTSPS) of the bound Pol II. P-TEFb also phosphorylates and activates SPT5 and TAT-SF1. SPT5 is a universal transcription factor that helps recruit 5'-capping enzyme to Pol II with a CTD phosphorylated at Ser-5. TAF-SF1 recruits components of the RNA splicing machinery to the ...
Mediator interacts with the pre-initiation complex, composed of RNA Polymerase II and general transcription factors TFIIB, TFIID, TFIIE, TFIIF, and TFIIH to stabilize and initiate transcription. [12] Studies of Mediator-RNA Pol II contacts in budding yeast have emphasized the importance of TFIIB-Mediator contacts in the formation of the complex.
(NER)TF II H is a general transcription factor that acts to recruit RNA Pol II to the promoters of genes. It functions as a DNA translocase, tracking along the DNA, reeling DNA into the Pol II cleft, and creating torsional strain leading to DNA unwinding [7]. It also unwinds DNA after a DNA lesion has been recognized by either the global genome ...