Nuclear Factor I/X (NFIX)

Nuclear factor I is a ubiquitous 47-kD dimeric DNA-binding protein whose recognition sequence, TGG(C/A)N(5)GCCAA, is found in the genomes of a number of DNA viruses. The same sequence occurs frequently in the human genome. The NFI protein stimulates initiation of adenovirus DNA replication in vitro and is capable of stimulating the transcription of genes in cooperation with other factors, such as the estrogen receptor (ESR). Santoro et al. (1988) gave a detailed analysis of NFI cDNAs isolated from the human, which, with similar analyses in other species, indicated that it is a member of a family of related proteins. Seisenberger et al. (1993) isolated 2 phages containing the second exon and flanking intron regions of the human gene for NFI/X, which has been designated NFIX.