Rearrangement and expression of immunoglobulin light chain genes can precede heavy chain expression during normal B cell development in mice.
In mouse mutants incapable of expressing mu chains, VkappaJkappa joints are detected in the CD43(+) B cell progenitors. In agreement with these earlier results, we show by a molecular single cell analysis that 4-7% of CD43(+) B cell progenitors in wild-type mice rearrange immunoglobulin (Ig)kappa genes before the assembly of a productive VHDHJH joint. Thus, mu chain expression is not a prerequisite to Igkappa light chain gene rearrangements in normal development. Overall, approximately 15% of the total CD43(+) B cell progenitor population carry Igkappa gene rearrangements in wild-type mice. Together with the results obtained in the mouse mutants, these data fit a model in which CD43(+) progenitors rearrange IgH and Igkappa loci independently, with a seven times higher frequency in the former. In addition, we show that in B cell progenitors VkappaJkappa joining rapidly initiates kappa chain expression, irrespective of the presence of a mu chain.
Novobrantseva
T I
TI
Institute for Genetics, University of Cologne,Weyertal 121, 50931 Cologne, Germany. ntanya@mac.genetik.umi-koeln.de
Martin
V M
VM
Pelanda
R
R
Müller
W
W
Rajewsky
K
K
Ehlich
A
A
D000818:Animals; D015703:Antigens, CD; D001402:B-Lymphocytes / Q000276:immunology*; D018507:Gene Expression Regulation, Developmental / Q000235:genetics*; D015321:Gene Rearrangement / Q000235:genetics; D005803:Genes, Immunoglobulin / Q000235:genetics; D007143:Immunoglobulin Heavy Chains / Q000235:genetics*; D007147:Immunoglobulin Light Chains / Q000235:genetics*; D051917:Leukosialin; D051379:Mice; D016133:Polymerase Chain Reaction; D011995:Recombination, Genetic / Q000235:genetics; D017422:Sequence Analysis, DNA; D012795:Sialoglycoproteins / Q000235:genetics; D013234:Stem Cells / Q000276:immunology
D015703:Antigens, CD; D007143:Immunoglobulin Heavy Chains; D007147:Immunoglobulin Light Chains; D051917:Leukosialin; D012795:Sialoglycoproteins; C497863:Spn protein, mouse