The genes for transcription factor nuclear factor I give rise to corresponding splice variants between vertebrate species.

Nuclear Factor I (NFI) proteins are DNA binding proteins functioning as transcription and replication factors. As part of a study of the diversity of the Nuclear Factor I protein family, we isolated and sequenced seven NFI cDNA clones from a chicken promacrophage library. Five of these clones are derived from the NFI-A gene, the other two from the NFI-C gene. Comparison of the deduced chicken NFI amino acid sequences with mammalian NFI sequences reveals that there are corresponding vertebrate isoforms, indicating a strong conservation of NFI structure during evolution. This finding leads to the prediction that more mammalian isoforms will be discovered corresponding to the chicken NFI variants reported here.