Deletions of immunoglobulin C kappa region characterized by the circular excision products in mouse splenocytes.

摘要: We have identified circular DNAs containing the kappa light chain constant region (C kappa), as well excision products of V kappa-J and lambda-J lambda joining in adult mouse splenocytes. Analysis C kappa-positive DNA clones revealed two recombination sites (intron recombining sequence [IRS]1 -2) within germline J kappa-C intron (RS) located downstream exon. While RS contains a conserved heptamer nonamer separated by 23-bp spacer on 5' side, IRS1 is an isolated without obvious nonamer, IRS2 variant heptamer, CACAAAA. Since recombined with both (23-bp signal) (12-bp significant frequency, seem to dual signals. These findings provide direct evidence that deletion preceding gene rearrangement can occur looping out excision. Increased accessibility inefficient recombinational loci may enable recombinase accept wide signal variation.