Mutation of immunoglobulin Jξ splice sites does not affect the rearrangement frequency of Jξ segments

The rabbit b9 kappa 1 locus contains 5 joining (J chi) gene segments, only two of which, J chi 1 and J chi 2, are utilized in assembly of a complete variable region gene (as shown by Akimenko, M.-A., Mariamé, B. and Rougeon, F. (1986) Proc. natl. Acad. Sci. (Wash.), 83, 5180-5183). J chi 4 and J chi 5 do not rearrange because of deficient recombination signal sequences. The J chi 3 gene segment is also not rearranged and has a non-functional splice site. In view of the proposed relationship between transcription and rearrangement of immunoglobulin genes, we sought to determine whether splicing of the germline transcript is implicated in the rearrangement process. We addressed this question by introducing mutations in the splice sites of the J chi segments of an unrearranged kappa light chain immunoglobulin transgene. Rearrangement was analysed by polymerase chain reaction on transgenic spleen DNA. We observed that mutation of the splice sites had no effect on the utilization of the J chi gene segments, demonstrating that there is no relationship between splicing and rearrangement.