DNA-directed RNA polymerase I subunit RPA1 (Polr1a)

DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates. Largest and catalytic core component of RNA polymerase I which synthesizes ribosomal RNA precursors.

Forms the polymerase active center along with the second largest subunit. A single stranded DNA template strand of the promoter is positioned within the central active site cleft of Pol I.