This family represents the Interferon regulatory factor 8 (IRF8) which plays essential roles in host defense, hematopoietic differentiation, and immune response. It is a transcription factor that specifically binds to the upstream regulatory region of type I interferon (IFN) and IFN-inducible MHC class I genes (the interferon consensus sequence (ICS)) []. It may act as a transcriptional activator or repressor and may play a negative regulatory role in cells of the immune system. It is involved in CD8+ dendritic cell differentiation by forming a complex with the BATF-JUNB heterodimer in immune cells, leading to recognition of AICE sequence (5'-TGAnTCA/GAAA-3'), an immune-specific regulatory element, followed by cooperative binding of BATF and IRF8 and activation of genes. It may be required for the development of plasmacytoid dendritic cells (pDCs), which produce most of the type I IFN in response to viral infection. It also positively regulates macroautophagy in dendritic cells [].This entry also includes some uncharacterised virus proteins that contain the IRF tryptophan pentad repeat, which is a DNA-binding domain.
