NCIt definition : A heterotetrameric complex that plays a role in the transcriptional activation of
major histocompatibility class II genes and consists of 2 molecules of DNA-binding
protein RFX5 and one each of regulatory factor X-associated protein (RFXAP) and DNA-binding
protein RFXANK.;
NCIt note : Regulatory factor X binds to X-box sequences in gene promoters. (UniProt);