What is the difference between RNA Pol I and Pol III?
RNA polymerase I (RNAPI) transcribes rRNA genes, RNA polymerase II (RNAPII) transcribes mRNA, miRNA, snRNA, and snoRNA genes, and RNA polymerase III (RNAPIII) transcribes tRNA and 5S rRNA genes. This is in contrast with prokaryotes where a single RNA polymerase is responsible for the transcription of all genes.
What does pol II do?
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 Pol lll?
In eukaryote cells, RNA polymerase III (also called Pol III) is a protein that transcribes DNA to synthesize ribosomal 5S rRNA, tRNA and other small RNAs. The genes transcribed by RNA Pol III fall in the category of “housekeeping” genes whose expression is required in all cell types and most environmental conditions.
Does RNA Pol I need a promoter?
Initiation. Pol I requires no TATA box in the promoter, instead relying on an upstream control element (UCE) located between −200 and −107, and a core element located between −45 and +20.
Does RNA pol I need a promoter?
Which are boxes that can be part of RNA polymerase II promoters?
The TATA box, Inr, MTE, DPE, and DCE are recognition sites for the binding of transcription factor TFIID. It should be noted, however, that there are multiple forms of TFIID and TFIID-related protein complexes that could potentially interact with the core promoter.
Does DNA polymerase III proofreading?
In bacteria, all three DNA polymerases (I, II and III) have the ability to proofread, using 3′ → 5′ exonuclease activity. When an incorrect base pair is recognized, DNA polymerase reverses its direction by one base pair of DNA and excises the mismatched base.
What does the replisome consist of?
The replisome is composed of a number of proteins including helicase, RFC, PCNA, gyrase/topoisomerase, SSB/RPA, primase, DNA polymerase III, RNAse H, and ligase.