Lack of feedback inhibition of V kappa gene rearrangement by productively rearranged alleles

Circular DNAs excised by immunoglobulin kappa chain gene rearrangements were cloned and characterized. 16 of 17 clones examined were double recombination products containing a V kappa-J kappa rearrangement (coding joint) as well as the reciprocal element (signal joint) of another V kappa-J kappa rearrangement. These products suggested multiple recombination, primary inversion, and secondary excision. In primary events, 5 of 16 translational reading frames were in-phase. Thus, V kappa gene rearrangement may not be inhibited by the presence of a productively rearranged allele. An unusually large trinucleotide (P) insertion forming a palindrome of 12 nucleotides was also observed in one of the coding joints.