Recognizes the ribosomal RNA gene promoter and activates transcription mediated by RNA polymerase I (Pol I) through cooperative interactions with the transcription factor SL1/TIF-IB complex. It binds specifically to the upstream control element and can activate Pol I promoter escape. {ECO:0000269|PubMed:11250903, ECO:0000269|PubMed:11283244, ECO:0000269|PubMed:16858408, ECO:0000269|PubMed:28777933, ECO:0000269|PubMed:7982918}. This is the function of ENSG00000108312 (UBTF, upstream binding transcription factor).