IDENTIFICATION OF ETS-RELATED AND NOTCH-RELATED SUBUNITS IN GA BINDING-PROTEIN

Recombinant cDNA clones that encode two distinct subunits of the transcription factor GA binding protein (GABP) have been isolated. The predicted amino add sequence of one subunit, GABP-alpha, exhibits similarity to the sequence of the product of the ets-1 proto-oncogene in a region known to encompass the Ets DNA binding domain. The sequence of the second subunit, GABP-beta, contains four 33-amino acid repeats located dose to the NH2-terminus of the subunit. The sequences of these repeats are similar to repeats in several transmembrane proteins, including Notch from Drosophila melanogaster and Glp-1 and Lin-12 from Caenorhabditis elegans. Avid, sequence-specific binding to DNA required the presence of both polypeptides, revealing a conceptual convergence of nuclear transforming proteins and membrane-anchored proteins implicated in developmentally regulated signal transduction processes.