Abstract
Interferon regulatory factor 4 (IRF-4) is a transcription factor involved in the immune response against infection. In particular, IRF-4 plays an essential role in lymphocyte cells, regulating B and T cell maturation as well as the development of CD4+ dendritic cells. Although IRF -4 was originally identified as an oncogene, it has been recently demonstrated to be a tumor suppressor in BCRIABL-induced acute B-lymphoblastic leukemia (B-ALL). IRF-4 is mainly located in the nucleus. However, it has been reported that IRF -4 might have a relevant cytoplasmic function essential for the tumor suppressor function. In an attempt to match function to localization, we characterized the location of eleven different IRF-4 mutants. These studies suggest that the DNA binding domain of IRF -4 is directly associated with its nuclear role as a transcription factor. Similarly, the IRF-associated domain (lAD) might be implicated in the cytoplasmic function as a tumor suppressor. Future studies will elucidate with narrower precision the section within the lAD domain that is more strongly implicated in the tumor suppressor activity.