Immunoglobulin light chain transcripts with altered V regions in Burkitt's lymphoma cell lines producing short mu chains.

The Burkitt lymphoma cell lines Ly91, Ly47 and Ly66 produce short mu chains in the absence of associated light (L) chains. mu mRNA lack two-thirds of the variable (V) region due to an alternate splicing event that takes place within V genes. L chain genes were found to be rearranged in these lines and to lead to transcripts with altered V regions. Although these abnormal transcripts displayed specific abnormalities in each cell line, they shared some features, including large deletions involving the V-J junction. In one cell line, L chain transcripts made up of either V kappa I subgroup gene J kappa 3 or V kappa IV gene-J kappa 4 recombination products bore a similar alteration: the donor splice site of the rearranged J kappa segment was modified, leading to the alternate use of the donor site of either the leader peptide exon or the next 3' unrearranged J kappa segment.