NFX1 is a transcriptional repressor capable of binding to the conserved X box motif of HLA-DRA and other MHC class II genes in vitro. It may play a role in the inflammatory response, regulating its duration by limiting the period in which class II MHC molecules are induced by IFN gamma. The RING type zinc finger domain interacts with an ubiquitin conjugating enzyme (E2) and facilitates ubiquitination.