title: Critical roles of the immunoglobulin intronic enhancers in maintaining the sequential rearrangement of IgH and Igk loci.
abstract: V(D)J recombination of immunoglobulin (Ig) heavy (IgH) and light chain genes occurs sequentially in the pro- and pre-B cells. To identify cis-elements that dictate this order of rearrangement, we replaced the endogenous matrix attachment region/Igk intronic enhancer (MiE(kappa)) with its heavy chain counterpart (Emu) in mice. This replacement, denoted EmuR, substantially increases the accessibility of both V(kappa) and J(kappa) loci to V(D)J recombinase in pro-B cells and induces Igk rearrangement in these cells. However, EmuR does not support Igk rearrangement in pre-B cells. Similar to that in MiE(kappa)(-/-) pre-B cells, the accessibility of V(kappa) segments to V(D)J recombinase is considerably reduced in EmuR pre-B cells when compared with wild-type pre-B cells. Therefore, Emu and MiE(kappa) play developmental stage-specific roles in maintaining the sequential rearrangement of IgH and Igk loci by promoting the accessibility of V, D, and J loci to the V(D)J recombinase.
authors.affiliation: Section of Molecular Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA.
authors.forename: Matthew A
authors.initials: MA
authors.lastname: Inlay
authors.forename: Tongxiang
authors.initials: T
authors.lastname: Lin
authors.forename: Heather H
authors.initials: HH
authors.lastname: Gao
authors.forename: Yang
authors.initials: Y
authors.lastname: Xu
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology / Q000378:metabolism; D004742:Enhancer Elements, Genetic / Q000502:physiology*; D015326:Gene Rearrangement, B-Lymphocyte, Heavy Chain; D015328:Gene Rearrangement, B-Lymphocyte, Light Chain; D007143:Immunoglobulin Heavy Chains / Q000235:genetics*; D007145:Immunoglobulin kappa-Chains / Q000235:genetics*; D007438:Introns / Q000502:physiology*; D051379:Mice; D008817:Mice, Mutant Strains; D013234:Stem Cells / Q000276:immunology / Q000378:metabolism
chemical_list: D007143:Immunoglobulin Heavy Chains; D007145:Immunoglobulin kappa-Chains