CLONING AND CHARACTERIZATION OF A C-MYC INTRON BINDING-PROTEIN (MIBP1)

The cDNA for a c-myc intron 1 binding protein 1 (MIBP1) in the rat was isolated from lambda gt11 and lambda ZAPII cDNA libraries. Sequencing of the cDNA clones revealed a long ORF which encoded a putative prote in of 2437 amino acid residues. This protein has two widely separated zinc finger regions, each of which carries C2H2 motifs. When expressed in E.coli as a fusion protein, part of the MIBP1 showed sequence-spec ific binding to the target sequence, i.e., a 9-bp sequence in the rat c-myc intron 1. MIBP1 is most likely the rat counterpart of human MHC binding protein-2 (MBP-2/HIV-EP2), based on the 86% similarity in nucl eotide sequence and 93% similarity in amino acid sequence. Northern bl otting revealed a high level of MIBP1 mRNA in the brain.