RFX5

RFX5 is a gene that encodes a regulatory factor involved in the major histocompatibility complex (MHC) class II genes. This gene is part of the regulatory factor X (RFX) family, which is characterized by a DNA-binding domain known as the winged-helix domain. The RFX5 gene is crucial for the immune system, as it plays a significant role in the transcription of MHC class II genes, which are essential for the immune response to pathogens.

Structure

The RFX5 gene is located on the long (q) arm of chromosome 1 at position 21. It spans approximately 19 kilobases and consists of 10 exons. The encoded protein, RFX5, is a 616 amino acid protein with a molecular weight of approximately 67 kDa.

Function

The RFX5 protein is a transcription factor that binds to X-boxes, a specific DNA sequence present in the promoter region of MHC class II genes. By binding to these X-boxes, RFX5 helps initiate the transcription of MHC class II genes, thereby playing a crucial role in the immune response.

Clinical Significance

Mutations in the RFX5 gene can lead to a rare immunodeficiency disorder known as MHC class II deficiency, or bare lymphocyte syndrome. This condition is characterized by a severe reduction in the number of MHC class II molecules, leading to a decreased ability to fight off infections.

Research

Research on the RFX5 gene and its encoded protein is ongoing, with studies focusing on understanding the precise mechanisms of its function and its role in disease. This research could potentially lead to new treatments for diseases associated with the immune system.

See Also

• Major histocompatibility complex
• Transcription factor
• Immunodeficiency

External Links

• RFX5 at the National Center for Biotechnology Information (NCBI)

Further Reading

• Steimle V, Otten LA, Zufferey M, Mach B. Complementation cloning of an MHC class II transactivator mutated in hereditary MHC class II deficiency (or bare lymphocyte syndrome). Cell. 1993 Apr 23;73(2):443-50.
• Nagarajan UM, Louis-Plence P, DeSandro A, Nilsen R, Bushey A, Boss JM. RFX-B is the gene responsible for the most common cause of the bare lymphocyte syndrome, an MHC class II immunodeficiency. Immunity. 1999 Jan;10(1):153-62.