title: Structure of extrachromosomal circular DNAs generated by immunoglobulin light chain gene rearrangements.
abstract: Recombination at the immunoglobulin kappa or lambda light chain locus generates extrachromosomal circular DNAs. We have isolated circular DNAs from adult mouse spleen cells and prepared a circular DNA clone library. We characterized four J kappa-positive and one J lambda 1-positive clones. The J kappa-clones contained both coding and signal joints of V kappa-J kappa joining, and the J lambda 1-clone contained a signal joint of V lambda 1-J lambda 1 joining. Genomic organization of the V kappa gene families used in these joints suggested the excision of circular DNA preceded by inversion. A specific dinucleotide (P) insertion in the coding joint was observed in two clones. Three coding joints were out of frame and one clone had an in-frame coding joint, although possibly combined with a pseudo-V kappa gene. These kappa-positive circular DNAs are possibly excised from the chromosome by secondary recombinations which replace non-productive primary rearrangements.
authors.affiliation: Department of Biophysics, Faculty of Science, Kyoto University Japan.
authors.forename: T
authors.initials: T
authors.lastname: Hirama
authors.forename: S
authors.initials: S
authors.lastname: Takeshita
authors.forename: Y
authors.initials: Y
authors.lastname: Yoshida
authors.forename: H
authors.initials: H
authors.lastname: Yamagishi
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D004270:DNA, Circular / Q000235:genetics*; D015321:Gene Rearrangement / Q000235:genetics*; D007133:Immunoglobulin Joining Region / Q000235:genetics; D007147:Immunoglobulin Light Chains / Q000235:genetics*; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D013154:Spleen
chemical_list: D004270:DNA, Circular; D007133:Immunoglobulin Joining Region; D007147:Immunoglobulin Light Chains