MHC class II regulatory factor RFX has a novel DNA-binding domain and a functionally independent dimerization domain.

摘要: The regulation of MHC class II gene expression controls T-cell activation and, hence, the immune response. Among nuclear factors observed to bind conserved DNA sequences in human leukocyte antigen (HLA) promoters, RFX is special interest: Its binding defective congenital HLA deficiency, a disease regulation. cloning an cDNA has allowed us show by transfection plasmid directing synthesis antisense RNA that regulatory factor. novel 979-amino-acid DNA-binding protein contains three structurally and functionally separate domains. 91-amino-acid domain distinct from other known motifs but may be distantly related helix-loop-helix motif. most striking property it can stably X box as either monomer or homodimer responsible for dimerization distant independent domain. This distinguishes dimeric proteins. It also implies two potential sites. We therefore speculate could form loop cross-linking X-box found far apart upstream genes.