DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates. Common component of RNA polymerases I and III which synthesize ribosomal RNA precursors and short non-coding RNAs including 5S rRNA, snRNAs, tRNAs and miRNAs, respectively. POLR1C/RPAC1 is part of the polymerase core and may function as a clamp element that moves to open and close the cleft. {ECO:0000250|UniProtKB:P07703, ECO:0000269|PubMed:20413673, ECO:0000269|PubMed:34671025, ECO:0000269|PubMed:34887565, ECO:0000269|PubMed:36271492, ECO:0000305|PubMed:26151409}. This is the function of POLR1C (RNA polymerase I and III subunit C, ENSG00000171453).