TATA box binding protein associated factor RNA Polymerase I subunit A is found in eukaryotes and is encoded by the gene TAF1A in humans. Its function is to aid transcription of DNA into RNA by binding to the promoter at the -10 TATA box site. It is a component of the transcription factor SL1/TIF-IB complex, involved in PIC assembly (pre-initiation complex) during RNA polymerase I-dependent transcription. The rate of PIC formation depends on the rate of association of this protein. This protein also stabilises nucleolar transcription factor 1/UBTF on rDNA [1,2].

1: Reconstitution of transcription factor SL1: exclusive binding of TBP by SL1 or TFIID subunits. Comai L, Zomerdijk JC, Beckmann H, Zhou S, Admon A, Tjian R; Science. 1994;266:1966-1972. PMID:7801123

2: TBP-TAF complex SL1 directs RNA polymerase I pre-initiation complex formation and stabilizes upstream binding factor at the rDNA promoter. Friedrich JK, Panov KI, Cabart P, Russell J, Zomerdijk JC; J Biol Chem. 2005;280:29551-29558. PMID:15970593