function:DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates. Component of RNA polymerase I which synthesizes ribosomal RNA precursors. Through its association with RRN3/TIF-IA may be involved in recruitment of Pol I to rDNA promoters.,similarity:Belongs to the eukaryotic RPA43 RNA polymerase subunit family.,subunit:Component of the RNA polymerase I (Pol I) complex consisting of at least 13 subunits (By similarity). Interacts with RRN3/TIF-IA.,tissue specificity:Widely expressed. Expressed in all fetal and adult tissues tested, with highest expression in fetal lung, liver, and kidney, and low expression in all adult tissues.,