Rearrangement of rat immunoglobulin E heavy-chain and c-myc genes in the B-cell immunocytoma IR162.

Mammalian B-cell lymphoid malignancies frequently display aberrant translocations involving the c-myc proto-oncogene and one of the immunoglobulin loci. We have observed and characterized such a translocation in the immunoglobulin E-producing rat immunocytoma IR162 by using recombinant DNA technology. We show here for the first time that a c-myc gene has recombined with the excluded allele of the nonfunctional epsilon heavy-chain immunoglobulin gene. This recombination has resulted in the loss of 5'-proximal DNA and, consequently, potential regulatory information from the body of the c-myc structural gene via joining to the epsilon heavy-chain switch region in a head-to-head, i.e., 5'-to-5', configuration. As discussed in this report, these results, together with the previous results of others, have important implications for immunoglobulin heavy-chain class switching mechanisms controlling normal and abnormal translocations.