ABSTRACT
Polyomavirus enhancer binding protein 2 (PEBP2) (1^1), also called core binding factor (CBF) (5), is a heterodimeric transcription factor composed of two different subunits, a and ß. The a subunit binds di rectly to a specific DNA sequence, RACCRCA (2,5), while the ß sub unit does not by itself contact DNA but facilitates the DNA-binding ac tivity of the a subunit through allosteric interactions (2,5). The a subunit shares a 128-amino acid region of high homology with the D rosophila segmentation gene runt (6) and the human A M L ] gene (7). The con served region, termed Runt dom ain is responsible for both DNA binding and heterodimerization with the ß subunit(8,9). After the identification of the first member of the a subunit, PEBP2aA (4), two additional members of the Runt family have subsequently been isolated in mice and humans: PEBP2aB (mouse homologue of AML1) (10), and PEBP2aC (11) or AML2 (12).
