PURIFICATION, CHARACTERIZATION, AND CDNA CLONING OF ABP-2 (ARYLPHORINGENE-SPECIFIC BINDING PROTEIN-2) THAT SPECIFICALLY BINDS TO THE ABP-1-BINDING SEQUENCE IN THE ARYLPHORIN GENE OF SARCOPHAGA-PEREGRINA

Previously, we demonstrated that ABP-I (arylphorin gene-specific bindi ng protein-1), which is suggested to be the transcriptional activator of the arylphorin gene of Sarcophaga peregrina, is present in NIH-Sape -4 cells, which do not express arylphorin. As well as ABP-1, these cel ls were found to contain another protein (ABP-2) that probably binds t o the same sequence as that to which ABP-I binds [Adachi, N., Kubo, T. , and Natori, S. (1993) J. Biochem. 114, 55-60]. We purified ABP-2 fro m a nuclear extract of NIH-Sape-4 cells and compared its DNA-binding a ctivity with that of ABP-1, Both ABP-I and ABP-S were found to bind to the same sequence in the arylphorin gene with the same affinity and s tability, but an ABP-2-specific hypersensitive site was detected by DN ase I footprinting analysis. Analyses of proteolytic fragments suggest ed that both ABP-1 and ABP-2 have Zn fingers showing high similarity w ith that of AEF-1, a transcriptional repressor of the Drosophila melan ogaster alcohol dehydrogenase gene that binds to a sequence very simil ar to that binding ABP-I and ABP-2. We isolated a candidate cDNA for A BP-S, and the protein it encoded contained nine Zn fingers and regions rich in alanine, glutamine, serine/threonine, glycine, histidine, and asparagine.