Proteins Expressed by the c-myc Oncogene in Lymphomas of Human and Avian Origin

We have prepared antisera against synthetic peptides corresponding to the C-terminal region of the avian and human myc oncogene coding sequences. Immunoprecipitates from avian and human cells show two major proteins which, by the criteria of hybrid-selected translation, transfection, and peptide-blocking assays, are the c-myc protein products. These proteins are phosphorylated nuclear proteins which are tightly bound to the nuclear matrix-lamin and which have a short half-life. Analysis of avian and human lymphoma cell lines containing rearranged c-myc alleles show significant changes in the ratio of the two proteins although only the avian lymphomas have increased quantities of c-myc protein.