The evolutionarily conserved Kruppel-associated box domain defines a subfamily of eukaryotic multifingered proteins

Bellefroid, E. J.; Poncelet, D. A.; Lecocq, P. J.

doi:10.2307/2356794

We have previously shown that the human genome includes hundreds of genes coding for putative factors related to the Kruppel zinc-finger protein, which regulates Drosophila segmentation. We report herein that about one-third of these genes code for proteins that share a very conserved region of about 75 amino acids in their N-terminal nonfinger portion. Homologous regions are found in a number of previously described finger proteins, including mouse Zfp-1 and Xenopus Xfin. We named this region the Kruppel-associated box (KRAB). This domain has the potential to form two amphipathic .alpha.-helices. Southern blot analysis of "zoo" blots suggests that the Kruppel-associated box is highly conserved during this evolution. Northern blot analysis shows that these genes are expressed in most adult tissues and are downregulated during in vitro terminal differentiation of human myeloid cells.