Products of a reciprocal chromosome translocation involving the c-myc gene in a murine plasmacytoma

The structures of the rearranged c-myc gene products derived from a rcp T(12;15) have been investigated in the MPC-11 (IgG2bκ) plasmacytoma. The rcp T(2;15) in MPC-11 is a reciprocal exchange between the c-myc gene on chromosome 15 and the immunoglobulin γ2a switch region (S(γ2a) on chromosome 12. The c-myc gene is broken within a 5'-nontranslated exon, thereby separating the promoter region of the normal c-myc gene from its protein coding sequences. This reciprocal rearrangement results in the loss of 11 base pairs of c-myc sequence and 300 base pairs of S(γ2a) sequence at the point of recombination. Sequences that represent the promoter region of the normal c-myc gene are present in the 5'-myc reciprocal fragment. A comparison of the nucleotide sequences at the recombination site of a c-myc rearrangement reveals a common feature that may have mechanistic importance for these translocation events.