title: D-D recombination diversifies the CDR 3 region of chicken immunoglobulin heavy chains.
abstract: The occurrence of D-D recombination during the embryonic differentiation of chicken B cells was studied. Ig heavy (H) chains were amplified by polymerase chain reaction from day-12 bursal cDNA, and 30 random V-D-J regions were analysed by DNA sequencing. No gene conversion events were observed in any of the V regions, indicating that diversification of the H chains by gene conversion is not yet activated at this stage of embryonic B-cell development. In contrast, the V-D-J joint regions were extremely heterogeneous. Most of the sequenced V-D-J joints were formed by direct joining of the single-germline V mu 1 gene, one of the multiple-germline D elements, and the single J gene. However, three V-D-J regions were clearly longer in size, and their D-region structure indicated recombination between two or three different germline D elements. Thus, the present data suggest that D-D recombination may have a role in diversification of the Ig H-chain repertoire.
authors.affiliation: Department of Medical Microbiology, Turku University, Finland.
authors.forename: A
authors.initials: A
authors.lastname: Mansikka
authors.forename: P
authors.initials: P
authors.lastname: Toivanen
mesh_terms: D000818:Animals; D001483:Base Sequence; D002645:Chickens / Q000276:immunology*; D005785:Gene Conversion; D015321:Gene Rearrangement; D005803:Genes, Immunoglobulin; D007143:Immunoglobulin Heavy Chains / Q000235:genetics*; D008969:Molecular Sequence Data; D011995:Recombination, Genetic
chemical_list: D007143:Immunoglobulin Heavy Chains