Preferential rearrangement of V kappa 4 gene segments in pre-B cell lines.

Abstract

Examination of the in vitro V.kappa. gene rearrangements of murine adult bone marrow-derived pre-B cell lines reveals that 21 of 25 84%) cell lines have rearranged a member of the V.kappa.4 family. In contrast, analysis of two V.kappa. cDNA libraries prepared from LPS-stimulated adult spleen cells indicates that only 17% of the Ig.kappa. cDNAs contain sequences belonging to the V.kappa.4 gene family. Half of the pre-B cell lines examined also share an 8-kbp BamHI reciprocal product (rp). However, these rp do not involve the same V.kappa. gene, indicating that conserved BamHI sites exist 3'' of some V.kappa. genes. This rp is also readily detected in DNA from normal adult spleen cells, suggesting that the in vitro rearrangements examined in this study are representative of .kappa. rearrangements that occur in vivo. We suggest that, unlike the diverse V.kappa. repertoire expressed by mature B cells, the germline V.kappa. segments involved in initial rearrangements of the Ig.kappa. locus are highly restricted, and that an initial V.kappa.4 rearragement is probably followed by other, more random recombination events.