The function of RRN3 (RNA polymerase I transcription factor RRN3, ENSG00000085721) is as follows. Required for efficient transcription initiation by RNA polymerase I (Pol I). Required for the formation of the competent pre- initiation complex (PIC). {ECO:0000250, ECO:0000269|PubMed:10758157, ECO:0000269|PubMed:11250903, ECO:0000269|PubMed:11265758, ECO:0000269|PubMed:15805466}.