TATA box-binding protein-associated factor RNA polymerase I subunit C is an enzyme that in humans is encoded by the TAF1C gene. Initiation of transcription by RNA polymerase I requires the formation of a complex composed of the TATA-binding protein (TBP) and three TBP-associated factors (TAFs) specific for RNA polymerase I. This complex, known as SL1, binds to the core promoter of ribosomal RNA genes to position the polymerase properly and acts as a channel for regulatory signals. This gene encodes the largest SL1-specific TAF. Two transcripts encoding different isoforms have been identified. (provided by RefSeq)
Component of the transcription factor SL1/TIF-IB complex, which is involved in the assembly of the PIC(preinitiation complex) during RNA polymerase I-dependent transcription. The rate of PIC formation probably is primarily dependent on the rate of association of SL1/TIF-IB with the rDNA promoter. SL1/TIF-IB is involved in stabilization of nucleolar transcription factor 1/UBTF on rDNA. Formation of SL1/TIF-IB excludes the association of TBP with TFIID subunits. Recruits RNA polymerase I to the rRNA gene promoter via interaction with RRN3.