Aberrant Rearrangements at the Murine Light Chain Locus in Plasmacytomas

Abstract

Rearrangements at the k locus can be analysed at the molecular level by using a variety of DNA probes. For example, a productive k rearrangement (κ⁺) will hybridize with probes from the constant (Cκ) region, the J_κ and the intervening sequence (IVS) region between J_κ and C_κ. It will not hybridize to probes upstream (U) of the J_κ region (Figure 1). The same applies to certain non-productive κ rearrangements (_κ-) that are a result of a mistake in the VJ joining process or due to the use of V_ψ genes. In plasmacytomas, rearrangements are detected that hybridize only with the C_κ probe or both the C_κ and IVS probes, but not with the J_κ probe. This suggests that rearrangement occurred in the IVS region. We have previously described such a rearrangement in the NZB myeloma PC7183 (1). This rearrangement hybridizes only with the C_κ probe and also contains DNA from chromosome 15 as well as DNA from the S_µ region. In this report we describe the structure of the reciprocal product and the relationship of both recombinants to the parental germline C_κ locus germline chromosome 15 loci.