Several distinct "CCAAT" box binding proteins coexist in eukaryotic cells (albumin/transcription factors/tissue specificity)

Even though a "CCAAT" box element is localized %=80 base pairs upstream of the transcription Initia- tion site in many eukaryotic promoters, It is not recognized by a single ubiquitous transcription factor. We show here that such a sequence present in the rat albumin promoter binds a protein distinct from the CCAAT-binding transcription factor CTF/NFI or from the CCAAT-binding protein (CBP) previ- ously described. The protein binding to the albumin CCAAT sequence (ACF or albumin CCAAT factor) Is not exclusive to liver, since we found a protein with Identical properties in spleen.