Translocation of immunoglobulin VH genes in Burkitt lymphoma.

Abstract

Cell hybrids were produced between mouse myeloma cells, which do not produce immunoglobulin chains, and Burkitt lymphoma cells (Daudi), which express surface IgM. Daudi cells carry a reciprocal chromosome translocation between chromosomes 8 and 14, described as t(8;14)(q24;q32). The hybrids were studied for the expression of human immunoglobulin chains and human isozyme markers, for the presence of human chromosomes, and for the presence of the human genes for H chain variable regions (VH) and .mu. and .gamma. chain constant (C) regions. The results indicate that the expressed .mu. chain gene is on normal chromosome 14 in Daudi cells. The chromosome 14 involved in the translocation (14q+) carries the gene for C.mu. and C.gamma.1-4 and probably several genes for the variable region (V). Certain hybrids had lost both the chromosomes 14 but had retained the abnormal chromosome 8(8q-) that carries the terminal end of the long arm of chromosome 14. The hybrid cells with the 8q- chromosome contained human VH genes but not C.mu. or C.gamma. genes. Therefore, we conclude that, in the Daudi Burkitt lymphoma, the break in chromosome 14 occurred within the chromosome segment containing V region genes. As a result of the translocation some of these VH genes became associated with chromosome 8. It is possible that the expression of malignancy in Burkitt lymphoma is caused by immunoglobulin V region gene translocation resulting in activation of a gene on the long arm of human chromosome 8.