RFX5

A lack of MHC-II expression results in a severe immunodeficiency syndrome called MHC-II deficiency, or the bare lymphocyte syndrome (BLS; MIM 209920). At least 4 complementation groups have been identified in B-cell lines established from patients with BLS. The molecular defects in complementation groups B, C, and D all lead to a deficiency in RFX, a nuclear protein complex that binds to the X box of MHC-II promoters. The lack of RFX binding activity in complementation group C results from mutations in the RFX5 gene encoding the 75-kD subunit of RFX (Steimle et al., 1995). RFX5 is the fifth member of the growing family of DNA-binding proteins sharing a novel and highly characteristic DNA-binding domain called the RFX motif. Multiple alternatively spliced transcript variants have been found but the full-length natures of only two have been determined. [provided by RefSeq]

Full Name

regulatory factor X, 5 (influences HLA class II expression)

Function

Activates transcription from class II MHC promoters. Recognizes X-boxes. Mediates cooperative binding between RFX and NF-Y. RFX binds the X1 box of MHC-II promoters.

Biological Process

Biological Process negative regulation of transcription by RNA polymerase IIIEA:Ensembl
Biological Process positive regulation of MHC class II biosynthetic process1 PublicationIC:ComplexPortal
Biological Process positive regulation of transcription by RNA polymerase IIManual Assertion Based On ExperimentIDA:NTNU_SB
Biological Process regulation of transcription by RNA polymerase IIManual Assertion Based On ExperimentIBA:GO_Central

Cellular Location

Nucleus

Involvement in disease

Bare lymphocyte syndrome 2 (BLS2):
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.