What does RNA pol II transcribe?
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.
What does RNA pol II make?
RNA polymerase II catalyzes the synthesis of precursor mRNA. In eukaryotes, this RNA is generally longer than the final or “mature” mRNA, whose molecule is used as a template for protein synthesis.
Where is RNA polymerase II synthesized?
nucleus
RNA polymerase II is located in the nucleus and synthesizes all protein-coding nuclear pre-mRNAs.
Does RNA pol II have proofreading?
This proofreading mechanism enables Pol II to cleave the dinucleotide containing a mismatched 3′-RNA terminus through backtracking-dependent proofreading mechanism to regenerate a new post-translocation state, allowing Pol II to have a “second chance” to reselect the correct nucleotide for incorporation and elongation.
What are pol II promoters?
The RNA polymerase II core promoter is generally defined to be the sequence that directs the initiation of transcription. This simple definition belies a diverse and complex transcriptional module. There are two major types of core promoters – focused and dispersed.
What does DNA pol II do?
Upon binding of substrate, DNA Pol II binds nucleoside triphosphates to maintain the hydrogen bonded structure of DNA. The correct dNTP is then bound and the enzyme complex undergoes conformational changes of subdomains and amino acid residues. These conformational changes allow the rate of repair synthesis to be fast.
How is the Pol II activity regulated during transcription?
Transcription by RNA polymerase II (Pol II) is regulated by different processes, including alterations in chromatin structure, interactions between distal regulatory elements and promoters, formation of transcription domains enriched for Pol II and co-regulators, and mechanisms involved in the initiation, elongation.
Why is proofreading done during eukaryotic DNA transcription?
Proofreading, which corrects errors during DNA replication. Mismatch repair, which fixes mispaired bases right after DNA replication. DNA damage repair pathways, which detect and correct damage throughout the cell cycle.
Can transcription elongation factors proofread?
Possible Functions of SII In Vivo Our results showed that SII stimulates proofreading of the nascent RNA during normal processive elongation in vitro. Whether proofreading occurs in vivo remains an unanswered question, however.
What are Pol II transcription factors?
A minimal RNA polymerase II (pol II) transcription system comprises the polymerase and five general transcription factors (GTFs) TFIIB, -D, -E, -F, and -H. The addition of Mediator enables a response to regulatory factors. The GTFs are required for promoter recognition and the initiation of transcription.
What is the role of RNA polymerase 2 in transcription?
It catalyzes the transcription of DNA to synthesize precursors of mRNA and most snRNA and microRNA. 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.
What are RNA pol II elongation promoters?
RNA Pol II elongation promoters can be summarised in 3 classes. Chromatin structure-oriented factors (Histone posttranscriptional modifiers, e.g., Histone Methyltransferases) RNA Pol II catalysis-improving factors (Various interfering proteins and Pol II cofactors; see RNA polymerase II).
How many subunits are in RNA polymerase II?
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. RNA polymerase II of Saccharomyces cerevisiae consisting of all 12 subunits.