Insertion of an imprinted insulator into the IgH locus reveals developmentally regulated, transcription-dependent control of V(D)J recombination.
The assembly of antigen receptor loci requires a developmentally regulated and lineage-specific recombination between variable (V), diversity (D), and joining (J) segments through V(D)J recombination. The process is regulated by accessibility control elements, including promoters, insulators, and enhancers. The IgH locus undergoes two recombination steps, D-J(H) and then V(H)-DJ(H), but it is unclear how the availability of the DJ(H) substrate could influence the subsequent V(H)-DJ(H) recombination step. The Eμ enhancer plays a critical role in V(D)J recombination and controls a set of sense and antisense transcripts. We epigenetically perturbed the early events at the IgH locus by inserting the imprinting control region (ICR) of the Igf2/H19 locus or a transcriptional insulator devoid of the imprinting function upstream of the Eμ enhancer. The insertions recapitulated the main epigenetic features of their endogenous counterparts, including differential DNA methylation and binding of CTCF/cohesins. Whereas the D-J(H) recombination step was unaffected, both the insulator insertions led to a severe impairment of V(H)-DJ(H) recombination. Strikingly, the inhibition of V(H)-DJ(H) recombination correlated consistently with a strong reduction of DJ(H) transcription and incomplete demethylation. Thus, developmentally regulated transcription following D-J(H) recombination emerges as an important mechanism through which the Eμ enhancer controls V(H)-DJ(H) recombination.
CNRS UMR5089, Institut de Pharmacologie et de Biologie Structurale (IBPS), Toulouse, France Université de Toulouse, UPS, Institut de Pharmacologie et de Biologie Structurale (IPBS), Toulouse, France.
Nadine
N
Puget
Institute of Molecular Genetics (IGMM), CNRS UMR5535, and University of Montpellier I & II, Montpellier, France.
Ryutaro
R
Hirasawa
CNRS UMR5089, Institut de Pharmacologie et de Biologie Structurale (IBPS), Toulouse, France Université de Toulouse, UPS, Institut de Pharmacologie et de Biologie Structurale (IPBS), Toulouse, France.
Ngoc-Sa Nguyen
NS
Hu
CNRS UMR5089, Institut de Pharmacologie et de Biologie Structurale (IBPS), Toulouse, France Université de Toulouse, UPS, Institut de Pharmacologie et de Biologie Structurale (IPBS), Toulouse, France.
Nathalie
N
Laviolette-Malirat
Institute of Molecular Genetics (IGMM), CNRS UMR5535, and University of Montpellier I & II, Montpellier, France robert.feil@igmm.cnrs.fr ahmed.khamlichi@ipbs.fr.
Robert
R
Feil
CNRS UMR5089, Institut de Pharmacologie et de Biologie Structurale (IBPS), Toulouse, France Université de Toulouse, UPS, Institut de Pharmacologie et de Biologie Structurale (IPBS), Toulouse, France robert.feil@igmm.cnrs.fr ahmed.khamlichi@ipbs.fr.
Ahmed Amine
AA
Khamlichi
D000818:Animals; D019175:DNA Methylation / Q000235:genetics / Q000276:immunology; D004742:Enhancer Elements, Genetic / Q000235:genetics* / Q000276:immunology; D005786:Gene Expression Regulation / Q000235:genetics* / Q000276:immunology; D050438:Genes, Immunoglobulin Heavy Chain; D056426:Genetic Loci; D007143:Immunoglobulin Heavy Chains / Q000235:genetics* / Q000276:immunology; D007135:Immunoglobulin Variable Region / Q000235:genetics* / Q000276:immunology; D051379:Mice; D011995:Recombination, Genetic / Q000235:genetics / Q000276:immunology; D014158:Transcription, Genetic / Q000276:immunology; D060152:V(D)J Recombination / Q000235:genetics* / Q000276:immunology
D007143:Immunoglobulin Heavy Chains; D007135:Immunoglobulin Variable Region