title: Vκ gene repertoire and locus contraction are specified by critical DNase I hypersensitive sites within the Vκ-Jκ intervening region.
abstract: The processes of Ig gene locus contraction and looping during V(D)J-recombination are essential for creating a diverse Ab repertoire. However, no cis-acting sequence that plays a major role in specifying locus contraction has been uncovered within the Igκ gene locus. In this article, we demonstrate that a 650-bp sequence corresponding to DNase I hypersensitive sites HS1-2 within the mouse Igκ gene V-J intervening region binds CCCTC-binding factor and specifies locus contraction and long-range Vκ gene usage spanning 3.2 Mb in pre-B cells. We call this novel element Cer (for "contracting element for recombination"). Targeted deletion of Cer caused markedly increased proximal and greatly diminished upstream Vκ gene usage, higher allele usage, more splenic Igκ(+) B cells, and nonlineage-specific Igκ rearrangement in T cells. Relative to wild-type mice, Cer-deletion mice exhibited similar levels of Vκ gene germline transcription and H3K4me3 epigenetic marks but displayed a dramatic decrease in locus contraction in pre-B cells. Thus, our studies demonstrate that DNase I hypersensitive sites HS1-2 within the Vκ-Jκ intervening region are essential for controlling locus contraction and creating a diverse Ab repertoire.
authors.affiliation: Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9148, USA.
authors.forename: Yougui
authors.initials: Y
authors.lastname: Xiang
authors.forename: Sung-Kyun
authors.initials: SK
authors.lastname: Park
authors.forename: William T
authors.initials: WT
authors.lastname: Garrard
mesh_terms: D000818:Animals; D021901:DNA, Intergenic / Q000235:genetics*; D003850:Deoxyribonuclease I / Q000235:genetics* / Q000378:metabolism*; D055879:Gene Knock-In Techniques; D015322:Gene Rearrangement, B-Lymphocyte / Q000235:genetics*; D006801:Humans; D007127:Immunoglobulin Constant Regions / Q000235:genetics; D007143:Immunoglobulin Heavy Chains / Q000235:genetics; D007133:Immunoglobulin Joining Region / Q000235:genetics*; D007135:Immunoglobulin Variable Region / Q000235:genetics*; D007145:Immunoglobulin kappa-Chains / Q000235:genetics*; D019426:Integrases / Q000235:genetics; D051379:Mice; D018345:Mice, Knockout; D008822:Mice, Transgenic; D054420:Pre-B Cell Receptors / Q000235:genetics / Q000378:metabolism; D017384:Sequence Deletion / Q000276:immunology
chemical_list: D021901:DNA, Intergenic; D007127:Immunoglobulin Constant Regions; D007143:Immunoglobulin Heavy Chains; D007133:Immunoglobulin Joining Region; D007135:Immunoglobulin Variable Region; D007145:Immunoglobulin kappa-Chains; D054420:Pre-B Cell Receptors; C045073:Cre recombinase; D019426:Integrases; D003850:Deoxyribonuclease I