What is a Pol II gene?
What is a Pol II gene?
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 is Pol II transcribe?
Eukaryotic RNA polymerase II (pol II) is a 12-subunit DNA-dependent RNA polymerase that is responsible for transcribing nuclear genes encoding messenger RNAs and several small nuclear RNAs (1).
What is the difference between RNA Pol I and Pol III?
RNA polymerases I and III contain the same two non-identical α-like subunits, whereas polymerase II has two copies of a different α-like subunit. All three polymerases share four other common subunits. In addition, each RNA polymerase contains three to seven unique smaller subunits.
Which subunit of RNA polymerase 2 is highly phosphorylated?
CTD
The largest subunit of Pol II contains a repetitive carboxy-terminal domain (CTD) that becomes highly phosphorylated during transcription.
What is the role of DNA pol II?
In order to fix an error in the sequence, DNA Pol II catalyzes the repair of nucleotide base pairs. The N-terminal domain of DNA Pol II is responsible for the association and dissociation of the DNA strand to the catalytic subunit.
What is the function of polymerase II?
RNA polymerase II (Pol II) is the central enzyme that catalyses DNA-directed mRNA synthesis during the transcription of protein-coding genes.
How does RNA pol II stop?
Pol II escapes from the promoter when RNA reaches a length of ∼8–9 nucleotides, which constitutes the full length of the DNA–RNA hybrid that is observed during the elongation stage. Termination occurs when Pol II ceases RNA synthesis and both Pol II and the nascent RNA are released from the DNA template.
What does RNA pol I do?
RNA polymerase 1 (also known as Pol I) is, in higher eukaryotes, the polymerase that only transcribes ribosomal RNA (but not 5S rRNA, which is synthesized by RNA polymerase III), a type of RNA that accounts for over 50% of the total RNA synthesized in a cell.
What are the functions of DNA pol I II and III in prokaryotes?
Table 14.4. 1: Prokaryotic DNA Replication: Enzymes and Their Function
| Enzyme/protein | Specific Function |
|---|---|
| DNA pol I | Exonuclease activity removes RNA primer and replaces with newly synthesized DNA |
| DNA pol II | Repair function |
| DNA pol III | Main enzyme that adds nucleotides in the 5′-3′ direction |
Why is there a problem replicating the ends of linear DNA?
Why is there a problem replicating the ends of linear DNA? The primer used for lagging strand synthesis can’t be replaced because there is no available 3′ OH to add the replacement DNA on to. The telomeres represent large buffer zones of DNA sequence that do not code for biomolecules.
Does RNA polymerase II make mRNA?
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.
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