Chen J, Trounstine M, Kurahara C, Young F, Kuo CC, Xu Y, Loring JF, Alt FW, Huszar D:
B cell development in mice that lack one or both immunoglobulin
kappa light chain genes.
EMBO Journal 1993 Mar;12(3):821-30
ABSTRACT
We have generated mice that lack the ability to produce
immunoglobulin (Ig) kappa light chains by targeted deletion of J
kappa and C kappa gene segments and the intervening sequences in
mouse embryonic stem cells. In wild type mice, approximately 95% of
B cells express kappa light chains and only approximately 5% express
lambda light chains. Mice heterozygous for the J kappa C kappa
deletion have approximately 2-fold more lambda+ B cells than
wild-type littermates. Compared with normal mice, homozygous mutants
for the J kappa C kappa deletion have about half the number of B
cells in both the newly generated and the peripheral B cell
compartments, and all of these B cells express lambda light chains
in their Ig. Therefore, homozygous mutant mice appear to produce
lambda-expressing cells at nearly 10 times the rate observed in
normal mice. These findings demonstrate that kappa gene assembly
and/or expression is not a prerequisite for lambda gene assembly and
expression. Furthermore, there is no detectable rearrangement of 3'
kappa RS sequences in lambda+ B cells of the homozygous mutant mice,
thus rearrangements of these sequences, per se, is not required for
lambda light chain gene assembly. We discuss these findings in the
context of their implications for the control of Ig light chain gene
rearrangement and potential applications of the mutant animals.
