CLONING OF A CDNA-ENCODING A HUMAN PROTEIN WHICH BINDS A SEQUENCE IN THE C-MYC GENE SIMILAR TO THE INTERFERON-STIMULATED RESPONSE ELEMENT

A human cDNA clone encoding a c-myc promoter-binding protein (IRLB) wa s selected by screening a human fibroblast lambda gt11 phage library w ith the hexamer oligodeoxyribonucleotide (oligo) 5'-GGCGGGAAAAAGAACGGA , corresponding to the protein-binding element of human c-myc similar to the interferon-stimulated response element (ISRE). The lambda gt11 phage clone, encoding a fusion protein which bound the probe oligo, wa s used to create an strain of Escherichia coli. The deduced amino-acid sequence of the cloned protein contains a putative a-helix which is e xpected to act as the DNA-binding domain. DNase footprinting analysis and oligo-binding specificity assays showed that the cloned factor rec ognizes the ISRE-like element of the P2 promoter region of human c-myc .