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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 ...
Depending on the organism, a RNA polymerase can be a protein complex (multi-subunit RNAP) or only consist of one subunit (single-subunit RNAP, ssRNAP), each representing an independent lineage. The former is found in bacteria , archaea , and eukaryotes alike, sharing a similar core structure and mechanism. [ 1 ]
[1] [2] It is one of the three RNAP enzymes found in the nucleus of eukaryotic cells. [3] 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 initiation of the transcription is a multistep sequential process that involves several mechanisms: promoter location, initial reversible binding of RNA polymerase, conformational changes in RNA polymerase, conformational changes in DNA, binding of nucleoside triphosphate (NTP) to the functional RNA polymerase-promoter complex, and ...
RNA polymerase III (Pol III) transcribes small non-coding RNAs, including tRNAs, 5S rRNA, U6 snRNA, SRP RNA, and other stable short RNAs such as ribonuclease P RNA. [7] Structure of eukaryotic RNA polymerase II (light blue) in complex with α-amanitin (red), a strong poison found in death cap mushrooms that targets this vital enzyme
In archaea and eukaryotes, transcription initiation requires an RNA polymerase and a set of multiple GTFs to form a transcription preinitiation complex. Transcription initiation by eukaryotic RNA polymerase II involves the following GTFs: [7] [11] TFIIA – stabilizes the interaction between the TATA box and TFIID/TATA binding protein (TBP)
Archaeal transcription is the process in which a segment of archaeal DNA is copied into a newly synthesized strand of RNA using the sole Pol II-like RNA polymerase (RNAP). The process occurs in three main steps: initiation, elongation, and termination; and the end result is a strand of RNA that is complementary to a single strand of DNA.
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.