FunctionActivates transcription from class II MHC promoters. Activation requires the activity of the MHC class II transactivator (MHC2TA). May regulate other genes in the cell. RFX binds the X1 box of MHC-II promoters. Isoform RFX-B-delta5 is not involved in the positive regulation of MHC class II genes.
Involvement in diseaseDefects in RFXANK are a cause of bare lymphocyte syndrome type 2 (BLS2) [MIM:209920]; also known as hereditary MHC class II deficiency or HLA class II-deficient combined immunodeficiency. BLS2 is a severe combined immunodeficiency disease with early onset. It is characterized by a profound defect in constitutive and interferon-gamma induced MHC II expression, absence of cellular and humoral T-cell response to antigen challenge, hypogammaglobulinemia and impaired antibody production. The consequence include extreme susceptibility to viral, bacterial and fungal infections.
Sequence similaritiesContains 5 ANK repeats.
DomainThe third ankyrin repeat is required for association with the two other RFX subunits; RFX5 and RFXAP.