Extended duration of DH-JH rearrangement in immunoglobulin heavy chain transgenic mice: implications for regulation of allelic exclusion.
Here we show that suppression of VH-DJH rearrangement in mice bearing a mu heavy (H) chain transgene (mu-tg mice) is associated with an extended period of DH-JH rearrangement, the first step of Immunoglobulin H chain gene rearrangement. Whereas DH-JH rearrangement is normally initiated and completed at the pro-B cell stage, in mu-tg mice it continues beyond this stage and occurs most frequently at the small (late) pre-B stage. Despite ongoing DH-JH rearrangement in late pre-B cells of mu-tg mice, VH-DJH rearrangement is not detectable in these cells. We infer that the lack of VH-DJH rearrangement primarily reflects tg-induced acceleration of B cell differentiation past the stage at which rearrangement of VH elements is permissible. In support of this inference, we find that the normal representation of early B lineage subsets is markedly altered in mu-tg mice. We suggest that the effect of a productive VH-DJH rearrangement at an endogenous H chain allele may be similar to that of a mu-tg; i.e., cells that make a productive VH-DJH rearrangement on the first attempt rapidly progress to a developmental stage that precludes VH-DJH rearrangement at the other allele (allelic exclusion).
Chang
Y
Y
Fox Chase Cancer Center, Philadelphia, Pennsylvania 19111, USA.
Bosma
M J
MJ
Bosma
G C
GC
D000483:Alleles; D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology*; D001854:Bone Marrow Cells / Q000276:immunology; D002454:Cell Differentiation / Q000276:immunology; D004247:DNA / Q000235:genetics; D005434:Flow Cytometry; D015326:Gene Rearrangement, B-Lymphocyte, Heavy Chain / Q000235:genetics*; D005803:Genes, Immunoglobulin / Q000235:genetics*; D051379:Mice; D016513:Mice, SCID; D008822:Mice, Transgenic; D013154:Spleen / Q000276:immunology; D013234:Stem Cells / Q000276:immunology
D004247:DNA