Polymerase II Polypeptide I(POLR2I) is a member of the archaeal RpoM/eukaryotic RPA12/RPB9/RPC11 RNA polymerase family. POLR2I is a subunit of RNA polymerase II, which is a polymerase responsible for synthesizing messenger RNA in eukaryotes. DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the 4 ribonucleoside triphosphates as substrates. In addition POLR2I synthesizes mRNA precursors and numerous functional non-coding RNAs.