Fusion of DNA region to murine immunoglobulin heavy chain locus corresponds to plasmacytoma-associated chromosome translocation.

Murine plasmacytomas frequently exhibit a translocation of the distal region of chromosome 15 to the end of chromosome 12, where the immunoglobulin heavy chain locus resides. A candidate for the DNA across the chromosome fusion point is a cloned region of non-immunoglobulin DNA which in most plasmacytomas has recombined near the alpha heavy chain constant region gene. That the incoming DNA, provisionally designated LyR (lymphoid rearranging) DNA, does derive from chromosome 15 is shown here by blot analysis of DNA from two panels of somatic cell hybrids: hybridomas between an AKR T-lymphoma (Tikaut) and CBA mouse cells with a cytogenetically distinctive chromosome 15, and between mouse and Chinese hamster cells. LyR DNA segregated with chromosome 15 in all lines and the results assign LyR to the distal two thirds of that chromosome. This assignment, together with the previously reported high frequency of recombination between LyR and C(alpha) in plasmacytomas and associated alteration of LyR transcription suggests that translocation activates a LyR gene involved in plasmacytoma oncogenesis. Moreover, LyR rearrangement in certain T-lymphomas, such as the Tikaut line examined here, also implicate that gene in oncogenesis of some T-lymphomas.