RNA Polymerases are enzymes involved in the production of RNA. After the annealing of a primer, RNA polymerases build a complementary strand of RNA from free nucleotides using a strand of DNA as a template. The active form is a complex consisting of multiple subunits known as the RNA polymerase holoenzyme (Molecular mass ~400 kilodaltons) .
In Eukaryotes some RNA polymerases include:
- RNA_polymerase_I: Involved in the transcription of ribosomal RNA.
- RNA_polymerase_II: Transcribes all genes that code for proteins.
- RNA_polymerase_III: Involved in the transcription of transfer RNA (tRNA)
All three of the above RNA Polymerases' have a conserved core. This means that, in the case of RNA Polymerase II and III transcription can be initiated by the promoter sequence (varying TATA - box sequences) of the other RNA Polymerase. This leads to a varying level of polymerase specificity, depending on the other promoter sequence and transcription conditions.
- ↑ Hartl. D, Jones. E (2009), Genetics - Analysis Of Genes And Genomes, 7th Edition, Sudbury: Jones and Bartlett Publishers p346
- ↑ http://www.jbc.org/content/289/29/20396.abstract RNA Polymerase III Accurately Initiates Transcription from RNA Polymerase II Promoters in Vitro. Author: Sascha H. C. Duttke