RNA splicing generates a variant light chain from an aberrantly rearranged kappa gene.

Both C kappa regions in MPC 11 cells are rearranged into active transcripion units, one producing a normal kappa chain and the other an internally deleted kappa fragment lacking a V region. The gene coding for the kappa fragment mRNA is aberrantly rearranged and lacks a site for V leads to C kappa splicing. An alternative splicing event which deletes the V region from the nuclear RNA precursor generates the kappa fragment mRNA.