NF-kappa B and H2TF1 are transcription factors that bind to related DNA sequence motifs. NF-kappa B is a constitutive factor in mature B lymphocytes and is inducible in immature B cells and nonlymphoid cells. H2TF1 is a constitutive ubiquitous transcription factor that activates expression of major histocompatibility complex class I genes. We report here the isolation of two zinc finger genes. One, named MBP-2 (major histocompatibility complex-binding protein 2), encodes a factor that has DNA-binding properties similar, if not identical, to the H2TF1 transcription factor. The second, named KBP-1 (kappa-enhancer binding protein 1), encodes a factor that is similar to, but distinct from, NF-kappa B in its DNA-binding properties and methylation interference pattern, suggesting that at least two proteins can bind to the immunoglobulin kappa gene enhancer.